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  <xsd:element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorizedAnnualIncreaseNumber" id="ptct_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorizedAnnualIncreaseNumber" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="RoyaltyPurchaseAgreementPaymentMaximum" id="ptct_RoyaltyPurchaseAgreementPaymentMaximum" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="ContingentLiabilityCancellationAndForfeitureMilestonePotentialAchievementsPriorityReviewVoucherAmount" id="ptct_ContingentLiabilityCancellationAndForfeitureMilestonePotentialAchievementsPriorityReviewVoucherAmount" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="HopewellCampusMember" id="ptct_HopewellCampusMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="AssetAcquisitionNetSalesMilestone" id="ptct_AssetAcquisitionNetSalesMilestone" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="AssetAcquisitionInProcessResearchAndDevelopment" id="ptct_AssetAcquisitionInProcessResearchAndDevelopment" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="ConvertibleSeniorNotes3.0PercentDue2022Member" id="ptct_ConvertibleSeniorNotes3.0PercentDue2022Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="RoyaltyPurchaseAgreementTerminationPeriod" id="ptct_RoyaltyPurchaseAgreementTerminationPeriod" type="xbrli:durationItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="PaymentOfFinanceLeasePrincipal" id="ptct_PaymentOfFinanceLeasePrincipal" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="ContingentLiabilityCancellationAndForfeiture" id="ptct_ContingentLiabilityCancellationAndForfeiture" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorizedAnnualIncreaseAsPercentageOfStockOutstanding" id="ptct_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorizedAnnualIncreaseAsPercentageOfStockOutstanding" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="DebtInstrumentConvertibleThresholdConsecutiveTradingDayPeriod" id="ptct_DebtInstrumentConvertibleThresholdConsecutiveTradingDayPeriod" type="xbrli:durationItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="PaymentsForAssetAcquisitionsNetAssets" id="ptct_PaymentsForAssetAcquisitionsNetAssets" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="AdjustmentsToAdditionalPaidInCapitalReceivableFromInvestor" id="ptct_AdjustmentsToAdditionalPaidInCapitalReceivableFromInvestor" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="Percentageofnetproductsales" id="ptct_Percentageofnetproductsales" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="DevelopmentMilestonePaymentObligationsCancellationAndForfeiture" id="ptct_DevelopmentMilestonePaymentObligationsCancellationAndForfeiture" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="ContingentLiabilityMilestonePotentialAchievementsPriorityReviewVoucherAmount" id="ptct_ContingentLiabilityMilestonePotentialAchievementsPriorityReviewVoucherAmount" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="LesseeOperatingLeaseLiabilityPaymentsDueYearFiveandThereafter" id="ptct_LesseeOperatingLeaseLiabilityPaymentsDueYearFiveandThereafter" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="DevelopmentMilestonePaymentObligationsDueOnSecondAnniversaryYearOfMergerClosing" id="ptct_DevelopmentMilestonePaymentObligationsDueOnSecondAnniversaryYearOfMergerClosing" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="AssignedRoyaltyPaymentPercentage" id="ptct_AssignedRoyaltyPaymentPercentage" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="instant" />
  <xsd:element name="DepositsAndOtherAssetsNoncurrent" id="ptct_DepositsAndOtherAssetsNoncurrent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="RightsExchangeAgreementMember" id="ptct_RightsExchangeAgreementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="InventoriesAndCostOfProductSalesPolicyTextBlock" id="ptct_InventoriesAndCostOfProductSalesPolicyTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="Termforletterofcredit" id="ptct_Termforletterofcredit" type="xbrli:durationItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="UpfrontLicensingFee" id="ptct_UpfrontLicensingFee" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="DevelopmentMilestonePaymentObligationsNetofCancellationandForfeiture" id="ptct_DevelopmentMilestonePaymentObligationsNetofCancellationandForfeiture" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="MilestoneAxis" id="ptct_MilestoneAxis" type="xbrli:stringItemType" substitutionGroup="xbrldt:dimensionItem" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="MilestonePotentialAchievementsRegulatoryApproval" id="ptct_MilestonePotentialAchievementsRegulatoryApproval" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="HopewellNewBuildingMember" id="ptct_HopewellNewBuildingMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="DebtInstrumentAdditionalAmountAvailableForRepurchase" id="ptct_DebtInstrumentAdditionalAmountAvailableForRepurchase" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="RestrictedStockAndRestrictedStockUnitsMember" id="ptct_RestrictedStockAndRestrictedStockUnitsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="MarathonPharmaceuticalsLLCMember" id="ptct_MarathonPharmaceuticalsLLCMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="AvailableForSaleSecuritiesDebtMaturitiesOverOneYearFairValue" id="ptct_AvailableForSaleSecuritiesDebtMaturitiesOverOneYearFairValue" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="AccruedConsultingAndContractedResearchCurrent" id="ptct_AccruedConsultingAndContractedResearchCurrent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="DebtInstrumentConversionPeriodOnOrAfterAugust202018Member" id="ptct_DebtInstrumentConversionPeriodOnOrAfterAugust202018Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="MassBioMember" id="ptct_MassBioMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="RevenueRecognitionMilestonePotentialAchievements" id="ptct_RevenueRecognitionMilestonePotentialAchievements" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="ScheduleOfInterestExpenseRecognizedRelatedToConvertibleDebtTableTextBlock" id="ptct_ScheduleOfInterestExpenseRecognizedRelatedToConvertibleDebtTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FiniteLivedIntangibleAssetsAmortizationExpenseYearFiveAndThereafter" id="ptct_FiniteLivedIntangibleAssetsAmortizationExpenseYearFiveAndThereafter" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="AssignedRoyaltyPaymentRetainedPercentage" id="ptct_AssignedRoyaltyPaymentRetainedPercentage" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="instant" />
  <xsd:element name="ResearchAndDevelopmentEventMilestonesMember" id="ptct_ResearchAndDevelopmentEventMilestonesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FifthAnniversaryMember" id="ptct_FifthAnniversaryMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="DebtInstrumentConvertibleThresholdBusinessDays" id="ptct_DebtInstrumentConvertibleThresholdBusinessDays" type="xbrli:durationItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="CensaMember" id="ptct_CensaMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="AssetAcquisitionMilestoneAmount" id="ptct_AssetAcquisitionMilestoneAmount" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="SalesAllowanceAndOtherRelatedCosts" id="ptct_SalesAllowanceAndOtherRelatedCosts" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="Equity2009AndLongTermIncentivePlanAndStockIncentivePlan2013Member" id="ptct_Equity2009AndLongTermIncentivePlanAndStockIncentivePlan2013Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="MountainviewMember" id="ptct_MountainviewMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ContingentLiabilityMilestonePotentialAchievementsNetSalesMilestone" id="ptct_ContingentLiabilityMilestonePotentialAchievementsNetSalesMilestone" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="AgilisMember" id="ptct_AgilisMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ContingentConsiderationTransactionFees" id="ptct_ContingentConsiderationTransactionFees" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="ConvertibleInstrumentsPrincipalAndUnpaidInterestPayableUponEventsOfDefault" id="ptct_ConvertibleInstrumentsPrincipalAndUnpaidInterestPayableUponEventsOfDefault" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="EmflazaassetacquisitionMember" id="ptct_EmflazaassetacquisitionMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="LiabilityNetSalesMilestonesandRoyaltiesMember" id="ptct_LiabilityNetSalesMilestonesandRoyaltiesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="CostofGoodsandServiceExcludingAmortizationOfIntangibleAssets" id="ptct_CostofGoodsandServiceExcludingAmortizationOfIntangibleAssets" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="PercentageofSalesforRoyaltiesMember" id="ptct_PercentageofSalesforRoyaltiesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="DevelopmentandRegulatoryMilestoneMember" id="ptct_DevelopmentandRegulatoryMilestoneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="Numberofdistributors" id="ptct_Numberofdistributors" type="xbrli:integerItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="PercentOfMarketRate" id="ptct_PercentOfMarketRate" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="instant" />
  <xsd:element name="DebtInstrumentConvertibleThresholdSalePriceOfCommonStockConversionRateProductPercentageMaximum" id="ptct_DebtInstrumentConvertibleThresholdSalePriceOfCommonStockConversionRateProductPercentageMaximum" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="instant" />
  <xsd:element name="EmployeeStockPurchasePlanVotingPercentageLimitPercent" id="ptct_EmployeeStockPurchasePlanVotingPercentageLimitPercent" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="MilestoneDomain" id="ptct_MilestoneDomain" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="AssetAcquisitionResearchAndDevelopmentExpense" id="ptct_AssetAcquisitionResearchAndDevelopmentExpense" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="PaymentsForAssetAcquisitionsUpfrontPayment" id="ptct_PaymentsForAssetAcquisitionsUpfrontPayment" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="MinimumPercentageOfDebtPrincipalAmountByInstrumentHolders" id="ptct_MinimumPercentageOfDebtPrincipalAmountByInstrumentHolders" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="AssetAcquisitionDevelopmentAndRegulatoryMilestones" id="ptct_AssetAcquisitionDevelopmentAndRegulatoryMilestones" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="PaymentsOnDeferredConsiderationObligation" id="ptct_PaymentsOnDeferredConsiderationObligation" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="GrantAndCollaborationMember" id="ptct_GrantAndCollaborationMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="BusinessCombinationConsiderationLiabilityDeferredConsiderationPayable" id="ptct_BusinessCombinationConsiderationLiabilityDeferredConsiderationPayable" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="Numberofterms" id="ptct_Numberofterms" type="xbrli:integerItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" />
  <xsd:element name="LiabilityDevelopmentandRegulatoryMilestoneMember" id="ptct_LiabilityDevelopmentandRegulatoryMilestoneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="SalesMilestonesMember" id="ptct_SalesMilestonesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="AssetAcquisitionInitialMilestone" id="ptct_AssetAcquisitionInitialMilestone" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="AssetAcquisitionTransactionCosts" id="ptct_AssetAcquisitionTransactionCosts" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="LoanAdvance" id="ptct_LoanAdvance" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="NetDeferredTaxLiabilitiesConvertibleDebtInstruments" id="ptct_NetDeferredTaxLiabilitiesConvertibleDebtInstruments" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="StockIssuedDuringPeriodValueExchangeRights" id="ptct_StockIssuedDuringPeriodValueExchangeRights" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="ContingentLiabilityMilestonePotentialAchievementsProductSalesPercentage" id="ptct_ContingentLiabilityMilestonePotentialAchievementsProductSalesPercentage" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" />
  <xsd:element name="WellcomeTrustLimitedMember" id="ptct_WellcomeTrustLimitedMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorizedSharesSubjectToOutstandingAwards" id="ptct_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorizedSharesSubjectToOutstandingAwards" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="instant" />
  <xsd:element name="AkceaMember" id="ptct_AkceaMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="PropertyPlantAndEquipmentUsefulLifeTableTextBlock" id="ptct_PropertyPlantAndEquipmentUsefulLifeTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="DevelopmentMilestonePaymentObligations" id="ptct_DevelopmentMilestonePaymentObligations" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="DeferredResearchAndDevelopmentCosts" id="ptct_DeferredResearchAndDevelopmentCosts" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="ComputerEquipmentAndSoftwareMember" id="ptct_ComputerEquipmentAndSoftwareMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FurnitureFixturesAndLabEquipmentMember" id="ptct_FurnitureFixturesAndLabEquipmentMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantedExercisePriceAsPercentageOfFairMarketValueOfCommonStock" id="ptct_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantedExercisePriceAsPercentageOfFairMarketValueOfCommonStock" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" />
  <xsd:element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantedToStockholdersWithSpecifiedOwnershipPercentageExercisePriceAsPercentageOfFairMarketValueOfCommonStock" id="ptct_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantedToStockholdersWithSpecifiedOwnershipPercentageExercisePriceAsPercentageOfFairMarketValueOfCommonStock" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" />
  <xsd:element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardStockholdersSpecifiedOwnershipPercentage" id="ptct_ShareBasedCompensationArrangementByShareBasedPaymentAwardStockholdersSpecifiedOwnershipPercentage" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" />
  <xsd:element name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodExercisePrice" id="ptct_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodExercisePrice" type="dtr-types:perShareItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FirstFiveYearsMember" id="ptct_FirstFiveYearsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ThereAfterFiveYearsMember" id="ptct_ThereAfterFiveYearsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="DeferredTaxAssetsOperatingLossCarryforwardsLimitedbyIRCSection382" id="ptct_DeferredTaxAssetsOperatingLossCarryforwardsLimitedbyIRCSection382" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="OperatingLossCarryforwardsInNextTwelveMonths" id="ptct_OperatingLossCarryforwardsInNextTwelveMonths" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="EffectiveIncomeTaxRateReconciliationPermanentDifferences" id="ptct_EffectiveIncomeTaxRateReconciliationPermanentDifferences" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="DeferredTaxAssetsAmortization" id="ptct_DeferredTaxAssetsAmortization" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="DeferredTaxAssetsTaxCreditFederal" id="ptct_DeferredTaxAssetsTaxCreditFederal" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="DeferredTaxAssetsTaxCreditState" id="ptct_DeferredTaxAssetsTaxCreditState" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="DeferredTaxAssetsDeferredExpenseCapitalizedResearchAndDevelopmentCosts" id="ptct_DeferredTaxAssetsDeferredExpenseCapitalizedResearchAndDevelopmentCosts" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="DeferredTaxLiabilitiesConvertibleDebt" id="ptct_DeferredTaxLiabilitiesConvertibleDebt" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="AssignedRoyaltyPaymentsMember" id="ptct_AssignedRoyaltyPaymentsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="RoyaltyPurchaseAgreementMember" id="ptct_RoyaltyPurchaseAgreementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="LiabilitySaleOfFutureRoyaltiesCurrent" id="ptct_LiabilitySaleOfFutureRoyaltiesCurrent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="LiabilitySaleOfFutureRoyaltiesNoncurrent" id="ptct_LiabilitySaleOfFutureRoyaltiesNoncurrent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="NoncashRoyaltyRevenueSaleOfFutureRoyalties" id="ptct_NoncashRoyaltyRevenueSaleOfFutureRoyalties" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="NoncashInterestExpenseLiabilityRelatedToSaleOfFutureRoyalties" id="ptct_NoncashInterestExpenseLiabilityRelatedToSaleOfFutureRoyalties" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="ProceedsFromSaleOfFutureRoyalties" id="ptct_ProceedsFromSaleOfFutureRoyalties" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="LesseeOperatingLeaseWrittenNotificationPeriodToTerminate" id="ptct_LesseeOperatingLeaseWrittenNotificationPeriodToTerminate" type="xbrli:durationItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="DevelopmentMilestoneObligationPaymentsMade" id="ptct_DevelopmentMilestoneObligationPaymentsMade" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="LiabilitySaleOfFutureRoyalties" id="ptct_LiabilitySaleOfFutureRoyalties" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="LiabilitySaleOfFutureRoyaltiesRoyaltyRevenuePayable" id="ptct_LiabilitySaleOfFutureRoyaltiesRoyaltyRevenuePayable" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="LiabilitySaleOfFutureRoyaltiesInterestExpense" id="ptct_LiabilitySaleOfFutureRoyaltiesInterestExpense" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="ProceedsFromMilestonePaymentsReceived" id="ptct_ProceedsFromMilestonePaymentsReceived" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="LiabilityForSaleOfFutureRoyaltiesPolicyTextBlock" id="ptct_LiabilityForSaleOfFutureRoyaltiesPolicyTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="LeaseCostExcludingFinanceLeaseCosts" id="ptct_LeaseCostExcludingFinanceLeaseCosts" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="LiabilityForSaleOfFutureRoyaltiesTableTextBlock" id="ptct_LiabilityForSaleOfFutureRoyaltiesTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FinanceLeaseLiabilityPaymentsDueYearFiveAndAfter" id="ptct_FinanceLeaseLiabilityPaymentsDueYearFiveAndAfter" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="MachineryAndLabEquipmentMember" id="ptct_MachineryAndLabEquipmentMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="EffectiveIncomeTaxRateReconciliationChangeInUncertainTaxPositionsPercent" id="ptct_EffectiveIncomeTaxRateReconciliationChangeInUncertainTaxPositionsPercent" type="dtr-types:percentItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="SaleOfStockOptionToPurchaseSharesNotExercised" id="ptct_SaleOfStockOptionToPurchaseSharesNotExercised" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="SaleOfStockOptionPeriodToPurchaseShares" id="ptct_SaleOfStockOptionPeriodToPurchaseShares" type="xbrli:durationItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="SaleOfStockRemainingSharesAvailableForSaleAggregateOfferingValue" id="ptct_SaleOfStockRemainingSharesAvailableForSaleAggregateOfferingValue" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="InducementStockIncentivePlan2020Member" id="ptct_InducementStockIncentivePlan2020Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="SalesRebatesCurrent" id="ptct_SalesRebatesCurrent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="DebtInstrumentConversionPeriodOnOrAfterSeptember202023Member" id="ptct_DebtInstrumentConversionPeriodOnOrAfterSeptember202023Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ConvertibleDebtInstrumentsRedemptions" id="ptct_ConvertibleDebtInstrumentsRedemptions" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="LesseeOperatingLeaseLiabilityToBePaidAfterYearTwo" id="ptct_LesseeOperatingLeaseLiabilityToBePaidAfterYearTwo" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="OperatingLossCarryforwardsUtilized" id="ptct_OperatingLossCarryforwardsUtilized" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="OperatingLossCarryforwardsLimitedByIrcSection382Utilized" id="ptct_OperatingLossCarryforwardsLimitedByIrcSection382Utilized" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="RightsExchangeSettlementMeasurementInput" id="ptct_RightsExchangeSettlementMeasurementInput" type="xbrli:decimalItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" />
  <xsd:element name="RightsExchangeSettlementPotentialMilestonesValue" id="ptct_RightsExchangeSettlementPotentialMilestonesValue" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="AvailableForSaleDebtSecuritiesConversionPrice" id="ptct_AvailableForSaleDebtSecuritiesConversionPrice" type="dtr-types:perShareItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="instant" />
  <xsd:element name="TaxableIncomeBeforeNetOperatingLoss" id="ptct_TaxableIncomeBeforeNetOperatingLoss" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="PotentialMilestonePaymentsForfeitedByParticipatingRightholders" id="ptct_PotentialMilestonePaymentsForfeitedByParticipatingRightholders" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="LiabilityDevelopmentMilestoneMember" id="ptct_LiabilityDevelopmentMilestoneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="LiabilityRegulatoryMilestoneMember" id="ptct_LiabilityRegulatoryMilestoneMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="GainLossOnSettlementOfMilestones" id="ptct_GainLossOnSettlementOfMilestones" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="GainLossRecognizedOnChangeInFairValueOnContingentConsiderationForfeited" id="ptct_GainLossRecognizedOnChangeInFairValueOnContingentConsiderationForfeited" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="LeaseDisclosureTextBlock" id="ptct_LeaseDisclosureTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="LeaseSupplementalCashFlowDisclosureTableTextBlock" id="ptct_LeaseSupplementalCashFlowDisclosureTableTextBlock" type="dtr-types:textBlockItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="DeferredPayrollTaxLiabilityCaresAct" id="ptct_DeferredPayrollTaxLiabilityCaresAct" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="SettledValueOfMilestonePaymentsForfeitedByParticipatingRightholders" id="ptct_SettledValueOfMilestonePaymentsForfeitedByParticipatingRightholders" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="MilestoneObligationsRecorded" id="ptct_MilestoneObligationsRecorded" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="MilestonePayable" id="ptct_MilestonePayable" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="PotentialRoyaltiesDueNetProductSales" id="ptct_PotentialRoyaltiesDueNetProductSales" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="EmployeeDirectorAndConsultantStockOptionPlan1998EquityAndLongTermIncentivePlan2009AndStockIncentivePlan2013Member" id="ptct_EmployeeDirectorAndConsultantStockOptionPlan1998EquityAndLongTermIncentivePlan2009AndStockIncentivePlan2013Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ConvertibleDebtSecurity" id="ptct_ConvertibleDebtSecurity" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="NumberOfMutualFundsInvestedIn" id="ptct_NumberOfMutualFundsInvestedIn" type="xbrli:integerItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ClearpointEquityInvestmentsFvNi" id="ptct_ClearpointEquityInvestmentsFvNi" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="ClearpointEquityInvestmentFvniUnrealizedGainLoss" id="ptct_ClearpointEquityInvestmentFvniUnrealizedGainLoss" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="NumberOfDedicatedRoomsProvided" id="ptct_NumberOfDedicatedRoomsProvided" type="xbrli:integerItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="FinanceLeaseGuaranteedLeasePaymentsAnnual" id="ptct_FinanceLeaseGuaranteedLeasePaymentsAnnual" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="FinanceLeaseGuaranteedLeasePaymentsInitialPayment" id="ptct_FinanceLeaseGuaranteedLeasePaymentsInitialPayment" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="FinanceLeasePresentValueOfGuaranteedLeasePayments" id="ptct_FinanceLeasePresentValueOfGuaranteedLeasePayments" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" nillable="true" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element name="EmflazaMember" id="ptct_EmflazaMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="TranslarnaMember" id="ptct_TranslarnaMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="NumberOfMilestonePayments" id="ptct_NumberOfMilestonePayments" type="xbrli:integerItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ResearchAndDevelopmentAndSalesMilestonesMember" id="ptct_ResearchAndDevelopmentAndSalesMilestonesMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="RocheMember" id="ptct_RocheMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="NetSalesThresholdAchievedSalesMilestone" id="ptct_NetSalesThresholdAchievedSalesMilestone" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="PaymentOfRoyaltyObligation" id="ptct_PaymentOfRoyaltyObligation" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="WaylivraMember" id="ptct_WaylivraMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="TegsediMember" id="ptct_TegsediMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ClearpointEquityInvestmentMember" id="ptct_ClearpointEquityInvestmentMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="EquitySecuritiesFvNiUnrealizedGainLossForeignCurrency" id="ptct_EquitySecuritiesFvNiUnrealizedGainLossForeignCurrency" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element name="DepositsAndOtherAssetsNoncurrentMember" id="ptct_DepositsAndOtherAssetsNoncurrentMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="DeferredResearchAndDevelopmentAdvancePaymentsCurrent" id="ptct_DeferredResearchAndDevelopmentAdvancePaymentsCurrent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="DeferredResearchAndDevelopmentAdvancePaymentsNoncurrent" id="ptct_DeferredResearchAndDevelopmentAdvancePaymentsNoncurrent" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="DepositsAndOtherNoncurrentAssetsMember" id="ptct_DepositsAndOtherNoncurrentAssetsMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="MilestoneReceivable" id="ptct_MilestoneReceivable" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element name="DeferredTaxAssetsNoncashInterestExpense" id="ptct_DeferredTaxAssetsNoncashInterestExpense" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" abstract="false" nillable="true" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element name="ResearchAndDevelopmentEventMilestonesPeriodPayment1Member" id="ptct_ResearchAndDevelopmentEventMilestonesPeriodPayment1Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="ResearchAndDevelopmentEventMilestonesPeriodPayment2Member" id="ptct_ResearchAndDevelopmentEventMilestonesPeriodPayment2Member" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
  <xsd:element name="AtMarketOfferingSalesAgreementMember" id="ptct_AtMarketOfferingSalesAgreementMember" type="dtr-types:domainItemType" substitutionGroup="xbrli:item" abstract="true" nillable="true" xbrli:periodType="duration" />
</xsd:schema>
