<?xml version="1.0" encoding="us-ascii"?>
<!-- Created by Merrill Corporation -->
<!--XBRL document created with Merrill Bridge  6.1.177.0 -->
<!--Based on XBRL 2.1-->
<!--Created on: 2/29/2016 3:14:26 PM-->
<!--Modified on: 2/29/2016 3:14:27 PM-->
<link:linkbase xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xbrli="http://www.xbrl.org/2003/instance" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <roleRef xlink:type="simple" xlink:href="ptct-20151231.xsd#StatementConsolidatedBalanceSheets" roleURI="http://www.ptcbio.com/role/StatementConsolidatedBalanceSheets" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="ptct-20151231.xsd#StatementConsolidatedStatementsOfOperations" roleURI="http://www.ptcbio.com/role/StatementConsolidatedStatementsOfOperations" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="ptct-20151231.xsd#StatementConsolidatedStatementsOfComprehensiveLoss" roleURI="http://www.ptcbio.com/role/StatementConsolidatedStatementsOfComprehensiveLoss" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="ptct-20151231.xsd#StatementConsolidatedStatementsOfCashFlows" roleURI="http://www.ptcbio.com/role/StatementConsolidatedStatementsOfCashFlows" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="ptct-20151231.xsd#DisclosureFairValueOfFinancialInstrumentsAndMarketableSecuritiesDetails2" roleURI="http://www.ptcbio.com/role/DisclosureFairValueOfFinancialInstrumentsAndMarketableSecuritiesDetails2" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="ptct-20151231.xsd#DisclosureFixedAssetsDetails" roleURI="http://www.ptcbio.com/role/DisclosureFixedAssetsDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="ptct-20151231.xsd#DisclosureAccountsPayableAndAccruedExpensesDetails" roleURI="http://www.ptcbio.com/role/DisclosureAccountsPayableAndAccruedExpensesDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="ptct-20151231.xsd#DisclosureLongTermDebt2015ConvertibleNotesDetails2" roleURI="http://www.ptcbio.com/role/DisclosureLongTermDebt2015ConvertibleNotesDetails2" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="ptct-20151231.xsd#DisclosureEarningsPerShareDetails" roleURI="http://www.ptcbio.com/role/DisclosureEarningsPerShareDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="ptct-20151231.xsd#DisclosureIncomeTaxesDetails" roleURI="http://www.ptcbio.com/role/DisclosureIncomeTaxesDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <roleRef xlink:type="simple" xlink:href="ptct-20151231.xsd#DisclosureCommitmentsAndContingenciesDetails" roleURI="http://www.ptcbio.com/role/DisclosureCommitmentsAndContingenciesDetails" xmlns="http://www.xbrl.org/2003/linkbase" />
  <calculationLink xlink:role="http://www.ptcbio.com/role/StatementConsolidatedBalanceSheets" xlink:type="extended" xlink:title="00100 - Statement - Consolidated Balance Sheets" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_Assets" xlink:label="us-gaap_Assets" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_AssetsCurrent" xlink:label="us-gaap_AssetsCurrent_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_Assets" xlink:to="us-gaap_AssetsCurrent_635923556632931372" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="us-gaap_CashAndCashEquivalentsAtCarryingValue_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AssetsCurrent_635923556632931372" xlink:to="us-gaap_CashAndCashEquivalentsAtCarryingValue_635923556632931372" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_MarketableSecuritiesCurrent" xlink:label="us-gaap_MarketableSecuritiesCurrent_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AssetsCurrent_635923556632931372" xlink:to="us-gaap_MarketableSecuritiesCurrent_635923556632931372" order="2" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xlink:label="us-gaap_PrepaidExpenseAndOtherAssetsCurrent_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AssetsCurrent_635923556632931372" xlink:to="us-gaap_PrepaidExpenseAndOtherAssetsCurrent_635923556632931372" order="3" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ReceivablesNetCurrent" xlink:label="us-gaap_ReceivablesNetCurrent_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AssetsCurrent_635923556632931372" xlink:to="us-gaap_ReceivablesNetCurrent_635923556632931372" order="4" use="optional" weight="1" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="us-gaap_PropertyPlantAndEquipmentNet_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_Assets" xlink:to="us-gaap_PropertyPlantAndEquipmentNet_635923556632931372" order="2" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="ptct-20151231.xsd#ptct_DepositsAndOtherAssetsNoncurrent" xlink:label="ptct_DepositsAndOtherAssetsNoncurrent_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_Assets" xlink:to="ptct_DepositsAndOtherAssetsNoncurrent_635923556632931372" order="3" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="us-gaap_LiabilitiesAndStockholdersEquity" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_Liabilities" xlink:label="us-gaap_Liabilities_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesAndStockholdersEquity" xlink:to="us-gaap_Liabilities_635923556632931372" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_LiabilitiesCurrent" xlink:label="us-gaap_LiabilitiesCurrent_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_Liabilities_635923556632931372" xlink:to="us-gaap_LiabilitiesCurrent_635923556632931372" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent" xlink:label="us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesCurrent_635923556632931372" xlink:to="us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent_635923556632931372" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_DeferredRevenueCurrent" xlink:label="us-gaap_DeferredRevenueCurrent_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesCurrent_635923556632931372" xlink:to="us-gaap_DeferredRevenueCurrent_635923556632931372" order="2" use="optional" weight="1" priority="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_OtherLiabilitiesNoncurrent" xlink:label="us-gaap_OtherLiabilitiesNoncurrent_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_Liabilities_635923556632931372" xlink:to="us-gaap_OtherLiabilitiesNoncurrent_635923556632931372" order="2" use="optional" weight="1" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_LongTermDebtNoncurrent" xlink:label="us-gaap_LongTermDebtNoncurrent_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_Liabilities_635923556632931372" xlink:to="us-gaap_LongTermDebtNoncurrent_635923556632931372" order="3" use="optional" weight="1" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_StockholdersEquity" xlink:label="us-gaap_StockholdersEquity_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LiabilitiesAndStockholdersEquity" xlink:to="us-gaap_StockholdersEquity_635923556632931372" order="2" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_CommonStockValue" xlink:label="us-gaap_CommonStockValue_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_StockholdersEquity_635923556632931372" xlink:to="us-gaap_CommonStockValue_635923556632931372" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_AdditionalPaidInCapital" xlink:label="us-gaap_AdditionalPaidInCapital_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_StockholdersEquity_635923556632931372" xlink:to="us-gaap_AdditionalPaidInCapital_635923556632931372" order="2" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_StockholdersEquity_635923556632931372" xlink:to="us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_635923556632931372" order="3" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_RetainedEarningsAccumulatedDeficit" xlink:label="us-gaap_RetainedEarningsAccumulatedDeficit_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_StockholdersEquity_635923556632931372" xlink:to="us-gaap_RetainedEarningsAccumulatedDeficit_635923556632931372" order="4" use="optional" weight="1" />
  </calculationLink>
  <calculationLink xlink:role="http://www.ptcbio.com/role/StatementConsolidatedStatementsOfOperations" xlink:type="extended" xlink:title="00200 - Statement - Consolidated Statements of Operations" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ProfitLoss" xlink:label="us-gaap_ProfitLoss" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="us-gaap_NetIncomeLoss_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_ProfitLoss" xlink:to="us-gaap_NetIncomeLoss_635923556632931372" order="1" use="optional" weight="1" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="us-gaap_IncomeTaxExpenseBenefit_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetIncomeLoss_635923556632931372" xlink:to="us-gaap_IncomeTaxExpenseBenefit_635923556632931372" order="1" use="optional" weight="-1" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetIncomeLoss_635923556632931372" xlink:to="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_635923556632931372" order="2" use="optional" weight="1" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_OtherNonoperatingIncomeExpense" xlink:label="us-gaap_OtherNonoperatingIncomeExpense_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_635923556632931372" xlink:to="us-gaap_OtherNonoperatingIncomeExpense_635923556632931372" order="1" use="optional" weight="1" priority="5" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_InterestIncomeExpenseNonoperatingNet" xlink:label="us-gaap_InterestIncomeExpenseNonoperatingNet_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_635923556632931372" xlink:to="us-gaap_InterestIncomeExpenseNonoperatingNet_635923556632931372" order="2" use="optional" weight="1" priority="5" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_GainsLossesOnExtinguishmentOfDebt" xlink:label="us-gaap_GainsLossesOnExtinguishmentOfDebt_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_635923556632931372" xlink:to="us-gaap_GainsLossesOnExtinguishmentOfDebt_635923556632931372" order="3" use="optional" weight="1" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_OperatingIncomeLoss" xlink:label="us-gaap_OperatingIncomeLoss_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_635923556632931372" xlink:to="us-gaap_OperatingIncomeLoss_635923556632931372" order="4" use="optional" weight="1" priority="5" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_SalesRevenueNet" xlink:label="us-gaap_SalesRevenueNet_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OperatingIncomeLoss_635923556632931372" xlink:to="us-gaap_SalesRevenueNet_635923556632931372" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="ptct-20151231.xsd#ptct_NetProductSales" xlink:label="ptct_NetProductSales_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_SalesRevenueNet_635923556632931372" xlink:to="ptct_NetProductSales_635923556632931372" order="1" use="optional" weight="1" priority="2" />
    <loc xlink:type="locator" xlink:href="ptct-20151231.xsd#ptct_CollaborationAndGrantRevenue" xlink:label="ptct_CollaborationAndGrantRevenue_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_SalesRevenueNet_635923556632931372" xlink:to="ptct_CollaborationAndGrantRevenue_635923556632931372" order="2" use="optional" weight="1" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_OperatingExpenses" xlink:label="us-gaap_OperatingExpenses_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OperatingIncomeLoss_635923556632931372" xlink:to="us-gaap_OperatingExpenses_635923556632931372" order="2" use="optional" weight="-1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ResearchAndDevelopmentExpense" xlink:label="us-gaap_ResearchAndDevelopmentExpense_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OperatingExpenses_635923556632931372" xlink:to="us-gaap_ResearchAndDevelopmentExpense_635923556632931372" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_GeneralAndAdministrativeExpense" xlink:label="us-gaap_GeneralAndAdministrativeExpense_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OperatingExpenses_635923556632931372" xlink:to="us-gaap_GeneralAndAdministrativeExpense_635923556632931372" order="2" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="ptct-20151231.xsd#ptct_DeemedDividend" xlink:label="ptct_DeemedDividend_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_ProfitLoss" xlink:to="ptct_DeemedDividend_635923556632931372" order="2" use="optional" weight="-1" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_PreferredStockRedemptionDiscount" xlink:label="us-gaap_PreferredStockRedemptionDiscount_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_ProfitLoss" xlink:to="us-gaap_PreferredStockRedemptionDiscount_635923556632931372" order="3" use="optional" weight="1" priority="2" />
  </calculationLink>
  <calculationLink xlink:role="http://www.ptcbio.com/role/StatementConsolidatedStatementsOfComprehensiveLoss" xlink:type="extended" xlink:title="00300 - Statement - Consolidated Statements of Comprehensive Loss" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTax" xlink:label="us-gaap_ComprehensiveIncomeNetOfTax" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="us-gaap_NetIncomeLoss_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_ComprehensiveIncomeNetOfTax" xlink:to="us-gaap_NetIncomeLoss_635923556632931372" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToParent" xlink:label="us-gaap_OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToParent_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_ComprehensiveIncomeNetOfTax" xlink:to="us-gaap_OtherComprehensiveIncomeAvailableforsaleSecuritiesAdjustmentNetOfTaxPortionAttributableToParent_635923556632931372" order="2" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent" xlink:label="us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_ComprehensiveIncomeNetOfTax" xlink:to="us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent_635923556632931372" order="3" use="optional" weight="1" priority="2" />
  </calculationLink>
  <calculationLink xlink:role="http://www.ptcbio.com/role/StatementConsolidatedStatementsOfCashFlows" xlink:type="extended" xlink:title="00500 - Statement - Consolidated Statements of Cash Flows" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease" xlink:label="us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease_635726291626079763" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease_635726291626079763" xlink:to="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_635923556632931372" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="us-gaap_NetIncomeLoss_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_635923556632931372" xlink:to="us-gaap_NetIncomeLoss_635923556632931372" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_Depreciation" xlink:label="us-gaap_Depreciation_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_635923556632931372" xlink:to="us-gaap_Depreciation_635923556632931372" order="2" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_FairValueAdjustmentOfWarrants" xlink:label="us-gaap_FairValueAdjustmentOfWarrants_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_635923556632931372" xlink:to="us-gaap_FairValueAdjustmentOfWarrants_635923556632931372" order="3" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_PaidInKindInterest" xlink:label="us-gaap_PaidInKindInterest_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_635923556632931372" xlink:to="us-gaap_PaidInKindInterest_635923556632931372" order="4" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_AmortizationOfFinancingCosts" xlink:label="us-gaap_AmortizationOfFinancingCosts_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_635923556632931372" xlink:to="us-gaap_AmortizationOfFinancingCosts_635923556632931372" order="5" use="optional" weight="1" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_GainsLossesOnExtinguishmentOfDebt" xlink:label="us-gaap_GainsLossesOnExtinguishmentOfDebt_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_635923556632931372" xlink:to="us-gaap_GainsLossesOnExtinguishmentOfDebt_635923556632931372" order="6" use="optional" weight="-1" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_GainLossOnDispositionOfAssets1" xlink:label="us-gaap_GainLossOnDispositionOfAssets1_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_635923556632931372" xlink:to="us-gaap_GainLossOnDispositionOfAssets1_635923556632931372" order="7" use="optional" weight="-1" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_AccretionAmortizationOfDiscountsAndPremiumsInvestments" xlink:label="us-gaap_AccretionAmortizationOfDiscountsAndPremiumsInvestments_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_635923556632931372" xlink:to="us-gaap_AccretionAmortizationOfDiscountsAndPremiumsInvestments_635923556632931372" order="8" use="optional" weight="-1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ShareBasedCompensation" xlink:label="us-gaap_ShareBasedCompensation_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_635923556632931372" xlink:to="us-gaap_ShareBasedCompensation_635923556632931372" order="9" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets" xlink:label="us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_635923556632931372" xlink:to="us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_635923556632931372" order="10" use="optional" weight="-1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_IncreaseDecreaseInReceivables" xlink:label="us-gaap_IncreaseDecreaseInReceivables_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_635923556632931372" xlink:to="us-gaap_IncreaseDecreaseInReceivables_635923556632931372" order="11" use="optional" weight="-1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_IncreaseDecreaseInDepositOtherAssets" xlink:label="us-gaap_IncreaseDecreaseInDepositOtherAssets_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_635923556632931372" xlink:to="us-gaap_IncreaseDecreaseInDepositOtherAssets_635923556632931372" order="12" use="optional" weight="-1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities" xlink:label="us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_635923556632931372" xlink:to="us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities_635923556632931372" order="13" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_IncreaseDecreaseInOtherNoncurrentLiabilities" xlink:label="us-gaap_IncreaseDecreaseInOtherNoncurrentLiabilities_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_635923556632931372" xlink:to="us-gaap_IncreaseDecreaseInOtherNoncurrentLiabilities_635923556632931372" order="14" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_IncreaseDecreaseInDeferredRevenue" xlink:label="us-gaap_IncreaseDecreaseInDeferredRevenue_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations_635923556632931372" xlink:to="us-gaap_IncreaseDecreaseInDeferredRevenue_635923556632931372" order="15" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease_635726291626079763" xlink:to="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations_635923556632931372" order="2" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:label="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations_635923556632931372" xlink:to="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_635923556632931372" order="1" use="optional" weight="-1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_PaymentsToAcquireMarketableSecurities" xlink:label="us-gaap_PaymentsToAcquireMarketableSecurities_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations_635923556632931372" xlink:to="us-gaap_PaymentsToAcquireMarketableSecurities_635923556632931372" order="2" use="optional" weight="-1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ProceedsFromSaleAndMaturityOfMarketableSecurities" xlink:label="us-gaap_ProceedsFromSaleAndMaturityOfMarketableSecurities_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations_635923556632931372" xlink:to="us-gaap_ProceedsFromSaleAndMaturityOfMarketableSecurities_635923556632931372" order="3" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease_635726291626079763" xlink:to="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations_635923556632931372" order="3" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_RepaymentsOfLongTermDebt" xlink:label="us-gaap_RepaymentsOfLongTermDebt_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations_635923556632931372" xlink:to="us-gaap_RepaymentsOfLongTermDebt_635923556632931372" order="1" use="optional" weight="-1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_SaleOfStockConsiderationReceivedOnTransaction" xlink:label="us-gaap_SaleOfStockConsiderationReceivedOnTransaction_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations_635923556632931372" xlink:to="us-gaap_SaleOfStockConsiderationReceivedOnTransaction_635923556632931372" order="2" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ProceedsFromIssuanceOfCommonStock" xlink:label="us-gaap_ProceedsFromIssuanceOfCommonStock_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations_635923556632931372" xlink:to="us-gaap_ProceedsFromIssuanceOfCommonStock_635923556632931372" order="3" use="optional" weight="1" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ProceedsFromStockOptionsExercised" xlink:label="us-gaap_ProceedsFromStockOptionsExercised_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations_635923556632931372" xlink:to="us-gaap_ProceedsFromStockOptionsExercised_635923556632931372" order="4" use="optional" weight="1" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_PaymentsOfDebtIssuanceCosts" xlink:label="us-gaap_PaymentsOfDebtIssuanceCosts_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations_635923556632931372" xlink:to="us-gaap_PaymentsOfDebtIssuanceCosts_635923556632931372" order="5" use="optional" weight="-1" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_ProceedsFromConvertibleDebt" xlink:label="us-gaap_ProceedsFromConvertibleDebt_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations_635923556632931372" xlink:to="us-gaap_ProceedsFromConvertibleDebt_635923556632931372" order="6" use="optional" weight="1" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_EffectOfExchangeRateOnCashContinuingOperations" xlink:label="us-gaap_EffectOfExchangeRateOnCashContinuingOperations_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease_635726291626079763" xlink:to="us-gaap_EffectOfExchangeRateOnCashContinuingOperations_635923556632931372" order="4" use="optional" weight="1" priority="2" />
  </calculationLink>
  <calculationLink xlink:role="http://www.ptcbio.com/role/DisclosureFairValueOfFinancialInstrumentsAndMarketableSecuritiesDetails2" xlink:type="extended" xlink:title="40302 - Disclosure - Fair value of financial instruments and marketable securities (Details 2)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_AvailableForSaleSecuritiesAmortizedCost" xlink:label="us-gaap_AvailableForSaleSecuritiesAmortizedCost" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_AvailableForSaleSecuritiesAccumulatedGrossUnrealizedGainBeforeTax" xlink:label="us-gaap_AvailableForSaleSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AvailableForSaleSecuritiesAmortizedCost" xlink:to="us-gaap_AvailableForSaleSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_635923556632931372" order="1" use="optional" weight="-1" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_AvailableForSaleSecuritiesAccumulatedGrossUnrealizedLossBeforeTax" xlink:label="us-gaap_AvailableForSaleSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AvailableForSaleSecuritiesAmortizedCost" xlink:to="us-gaap_AvailableForSaleSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_635923556632931372" order="2" use="optional" weight="1" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_AvailableForSaleSecurities" xlink:label="us-gaap_AvailableForSaleSecurities_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AvailableForSaleSecuritiesAmortizedCost" xlink:to="us-gaap_AvailableForSaleSecurities_635923556632931372" order="3" use="optional" weight="1" priority="2" />
  </calculationLink>
  <calculationLink xlink:role="http://www.ptcbio.com/role/DisclosureFixedAssetsDetails" xlink:type="extended" xlink:title="40401 - Disclosure - Fixed assets (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="us-gaap_PropertyPlantAndEquipmentNet" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_PropertyPlantAndEquipmentGross" xlink:label="us-gaap_PropertyPlantAndEquipmentGross_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_PropertyPlantAndEquipmentNet" xlink:to="us-gaap_PropertyPlantAndEquipmentGross_635923556632931372" order="1" use="optional" weight="1" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:label="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_PropertyPlantAndEquipmentNet" xlink:to="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_635923556632931372" order="2" use="optional" weight="-1" priority="2" />
  </calculationLink>
  <calculationLink xlink:role="http://www.ptcbio.com/role/DisclosureAccountsPayableAndAccruedExpensesDetails" xlink:type="extended" xlink:title="40501 - Disclosure - Accounts payable and accrued expenses (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent" xlink:label="us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_EmployeeRelatedLiabilitiesCurrent" xlink:label="us-gaap_EmployeeRelatedLiabilitiesCurrent_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent" xlink:to="us-gaap_EmployeeRelatedLiabilitiesCurrent_635923556632931372" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="ptct-20151231.xsd#ptct_AccruedConsultingAndContractedResearchCurrent" xlink:label="ptct_AccruedConsultingAndContractedResearchCurrent_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent" xlink:to="ptct_AccruedConsultingAndContractedResearchCurrent_635923556632931372" order="2" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_AccruedProfessionalFeesCurrent" xlink:label="us-gaap_AccruedProfessionalFeesCurrent_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent" xlink:to="us-gaap_AccruedProfessionalFeesCurrent_635923556632931372" order="3" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_AccountsPayableCurrent" xlink:label="us-gaap_AccountsPayableCurrent_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent" xlink:to="us-gaap_AccountsPayableCurrent_635923556632931372" order="4" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_OtherAccruedLiabilitiesCurrent" xlink:label="us-gaap_OtherAccruedLiabilitiesCurrent_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent" xlink:to="us-gaap_OtherAccruedLiabilitiesCurrent_635923556632931372" order="5" use="optional" weight="1" />
  </calculationLink>
  <calculationLink xlink:role="http://www.ptcbio.com/role/DisclosureLongTermDebt2015ConvertibleNotesDetails2" xlink:type="extended" xlink:title="40602 - Disclosure - Long-term debt, 2015 Convertible Notes (Details 2)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_InterestExpenseDebt" xlink:label="us-gaap_InterestExpenseDebt" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_InterestExpenseDebtExcludingAmortization" xlink:label="us-gaap_InterestExpenseDebtExcludingAmortization_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_InterestExpenseDebt" xlink:to="us-gaap_InterestExpenseDebtExcludingAmortization_635923556632931372" order="1" use="optional" weight="1" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_AmortizationOfFinancingCosts" xlink:label="us-gaap_AmortizationOfFinancingCosts_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_InterestExpenseDebt" xlink:to="us-gaap_AmortizationOfFinancingCosts_635923556632931372" order="2" use="optional" weight="1" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_AmortizationOfDebtDiscountPremium" xlink:label="us-gaap_AmortizationOfDebtDiscountPremium_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_InterestExpenseDebt" xlink:to="us-gaap_AmortizationOfDebtDiscountPremium_635923556632931372" order="3" use="optional" weight="1" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_LongTermDebt" xlink:label="us-gaap_LongTermDebt" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_DebtInstrumentFaceAmount" xlink:label="us-gaap_DebtInstrumentFaceAmount_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LongTermDebt" xlink:to="us-gaap_DebtInstrumentFaceAmount_635923556632931372" order="1" use="optional" weight="1" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_DebtInstrumentUnamortizedDiscount" xlink:label="us-gaap_DebtInstrumentUnamortizedDiscount_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_LongTermDebt" xlink:to="us-gaap_DebtInstrumentUnamortizedDiscount_635923556632931372" order="2" use="optional" weight="-1" priority="2" />
  </calculationLink>
  <calculationLink xlink:role="http://www.ptcbio.com/role/DisclosureEarningsPerShareDetails" xlink:type="extended" xlink:title="40801 - Disclosure - Earnings per share (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic" xlink:label="us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="us-gaap_NetIncomeLoss_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic" xlink:to="us-gaap_NetIncomeLoss_635923556632931372" order="1" use="optional" weight="1" />
    <loc xlink:type="locator" xlink:href="ptct-20151231.xsd#ptct_DeemedDividend" xlink:label="ptct_DeemedDividend_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic" xlink:to="ptct_DeemedDividend_635923556632931372" order="2" use="optional" weight="-1" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_PreferredStockRedemptionDiscount" xlink:label="us-gaap_PreferredStockRedemptionDiscount_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic" xlink:to="us-gaap_PreferredStockRedemptionDiscount_635923556632931372" order="3" use="optional" weight="1" />
  </calculationLink>
  <calculationLink xlink:role="http://www.ptcbio.com/role/DisclosureIncomeTaxesDetails" xlink:type="extended" xlink:title="41201 - Disclosure - Income taxes (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_CurrentIncomeTaxExpenseBenefit" xlink:label="us-gaap_CurrentIncomeTaxExpenseBenefit" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_CurrentStateAndLocalTaxExpenseBenefit" xlink:label="us-gaap_CurrentStateAndLocalTaxExpenseBenefit_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_CurrentIncomeTaxExpenseBenefit" xlink:to="us-gaap_CurrentStateAndLocalTaxExpenseBenefit_635923556632931372" order="1" use="optional" weight="1" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_CurrentForeignTaxExpenseBenefit" xlink:label="us-gaap_CurrentForeignTaxExpenseBenefit_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_CurrentIncomeTaxExpenseBenefit" xlink:to="us-gaap_CurrentForeignTaxExpenseBenefit_635923556632931372" order="2" use="optional" weight="1" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_DeferredTaxAssetsLiabilitiesNet" xlink:label="us-gaap_DeferredTaxAssetsLiabilitiesNet" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_DeferredTaxAssetsNet" xlink:label="us-gaap_DeferredTaxAssetsNet_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_DeferredTaxAssetsLiabilitiesNet" xlink:to="us-gaap_DeferredTaxAssetsNet_635923556632931372" order="1" use="optional" weight="1" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_DeferredTaxAssetsGross" xlink:label="us-gaap_DeferredTaxAssetsGross_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_DeferredTaxAssetsNet_635923556632931372" xlink:to="us-gaap_DeferredTaxAssetsGross_635923556632931372" order="1" use="optional" weight="1" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities" xlink:label="us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_DeferredTaxAssetsGross_635923556632931372" xlink:to="us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities_635923556632931372" order="1" use="optional" weight="1" priority="3" />
    <loc xlink:type="locator" xlink:href="ptct-20151231.xsd#ptct_DeferredTaxAssetsAmortization" xlink:label="ptct_DeferredTaxAssetsAmortization_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_DeferredTaxAssetsGross_635923556632931372" xlink:to="ptct_DeferredTaxAssetsAmortization_635923556632931372" order="2" use="optional" weight="1" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_DeferredTaxAssetsPropertyPlantAndEquipment" xlink:label="us-gaap_DeferredTaxAssetsPropertyPlantAndEquipment_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_DeferredTaxAssetsGross_635923556632931372" xlink:to="us-gaap_DeferredTaxAssetsPropertyPlantAndEquipment_635923556632931372" order="3" use="optional" weight="1" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_DeferredTaxAssetsDeferredIncome" xlink:label="us-gaap_DeferredTaxAssetsDeferredIncome_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_DeferredTaxAssetsGross_635923556632931372" xlink:to="us-gaap_DeferredTaxAssetsDeferredIncome_635923556632931372" order="4" use="optional" weight="1" priority="2" />
    <loc xlink:type="locator" xlink:href="ptct-20151231.xsd#ptct_DeferredTaxAssetsTaxCreditFederal" xlink:label="ptct_DeferredTaxAssetsTaxCreditFederal_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_DeferredTaxAssetsGross_635923556632931372" xlink:to="ptct_DeferredTaxAssetsTaxCreditFederal_635923556632931372" order="5" use="optional" weight="1" priority="2" />
    <loc xlink:type="locator" xlink:href="ptct-20151231.xsd#ptct_DeferredTaxAssetsTaxCreditState" xlink:label="ptct_DeferredTaxAssetsTaxCreditState_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_DeferredTaxAssetsGross_635923556632931372" xlink:to="ptct_DeferredTaxAssetsTaxCreditState_635923556632931372" order="6" use="optional" weight="1" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsDomestic" xlink:label="us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsDomestic_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_DeferredTaxAssetsGross_635923556632931372" xlink:to="us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsDomestic_635923556632931372" order="7" use="optional" weight="1" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsStateAndLocal" xlink:label="us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsStateAndLocal_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_DeferredTaxAssetsGross_635923556632931372" xlink:to="us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsStateAndLocal_635923556632931372" order="8" use="optional" weight="1" priority="2" />
    <loc xlink:type="locator" xlink:href="ptct-20151231.xsd#ptct_DeferredTaxAssetsDeferredExpenseCapitalizedResearchAndDevelopmentCosts" xlink:label="ptct_DeferredTaxAssetsDeferredExpenseCapitalizedResearchAndDevelopmentCosts_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_DeferredTaxAssetsGross_635923556632931372" xlink:to="ptct_DeferredTaxAssetsDeferredExpenseCapitalizedResearchAndDevelopmentCosts_635923556632931372" order="9" use="optional" weight="1" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_DeferredTaxAssetsOther" xlink:label="us-gaap_DeferredTaxAssetsOther_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_DeferredTaxAssetsGross_635923556632931372" xlink:to="us-gaap_DeferredTaxAssetsOther_635923556632931372" order="10" use="optional" weight="1" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_DeferredTaxAssetsValuationAllowance" xlink:label="us-gaap_DeferredTaxAssetsValuationAllowance_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_DeferredTaxAssetsNet_635923556632931372" xlink:to="us-gaap_DeferredTaxAssetsValuationAllowance_635923556632931372" order="2" use="optional" weight="-1" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_DeferredIncomeTaxLiabilities" xlink:label="us-gaap_DeferredIncomeTaxLiabilities_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_DeferredTaxAssetsLiabilitiesNet" xlink:to="us-gaap_DeferredIncomeTaxLiabilities_635923556632931372" order="2" use="optional" weight="-1" priority="2" />
    <loc xlink:type="locator" xlink:href="ptct-20151231.xsd#ptct_DeferredTaxLiabilitiesConvertibleDebt" xlink:label="ptct_DeferredTaxLiabilitiesConvertibleDebt_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_DeferredIncomeTaxLiabilities_635923556632931372" xlink:to="ptct_DeferredTaxLiabilitiesConvertibleDebt_635923556632931372" order="1" use="optional" weight="1" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:label="us-gaap_EffectiveIncomeTaxRateContinuingOperations" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:to="us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate_635923556632931372" order="1" use="optional" weight="1" priority="2" />
    <loc xlink:type="locator" xlink:href="ptct-20151231.xsd#ptct_EffectiveIncomeTaskRateReconciliationNetOperatingLossesLimitation" xlink:label="ptct_EffectiveIncomeTaskRateReconciliationNetOperatingLossesLimitation_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:to="ptct_EffectiveIncomeTaskRateReconciliationNetOperatingLossesLimitation_635923556632931372" order="2" use="optional" weight="1" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:to="us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes_635923556632931372" order="3" use="optional" weight="1" priority="2" />
    <loc xlink:type="locator" xlink:href="ptct-20151231.xsd#ptct_EffectiveIncomeTaxRateReconciliationPermanentDifferences" xlink:label="ptct_EffectiveIncomeTaxRateReconciliationPermanentDifferences_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:to="ptct_EffectiveIncomeTaxRateReconciliationPermanentDifferences_635923556632931372" order="4" use="optional" weight="1" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseResearchAndDevelopment" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseResearchAndDevelopment_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:to="us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseResearchAndDevelopment_635923556632931372" order="5" use="optional" weight="1" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:to="us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance_635923556632931372" order="6" use="optional" weight="1" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:to="us-gaap_EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential_635923556632931372" order="7" use="optional" weight="1" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationOtherAdjustments" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationOtherAdjustments_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:to="us-gaap_EffectiveIncomeTaxRateReconciliationOtherAdjustments_635923556632931372" order="8" use="optional" weight="1" priority="2" />
  </calculationLink>
  <calculationLink xlink:role="http://www.ptcbio.com/role/DisclosureCommitmentsAndContingenciesDetails" xlink:type="extended" xlink:title="41301 - Disclosure - Commitments and contingencies (Details)" xmlns="http://www.xbrl.org/2003/linkbase">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDue" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDue" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OperatingLeasesFutureMinimumPaymentsDue" xlink:to="us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent_635923556632931372" order="1" use="optional" weight="1" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OperatingLeasesFutureMinimumPaymentsDue" xlink:to="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears_635923556632931372" order="2" use="optional" weight="1" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OperatingLeasesFutureMinimumPaymentsDue" xlink:to="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears_635923556632931372" order="3" use="optional" weight="1" priority="2" />
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2014/elts/us-gaap-2014-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears_635923556632931372" />
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="us-gaap_OperatingLeasesFutureMinimumPaymentsDue" xlink:to="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears_635923556632931372" order="4" use="optional" weight="1" priority="2" />
  </calculationLink>
</link:linkbase>
