Release Details

SOUTH PLAINFIELD, NJ – September 18, 2013 – PTC Therapeutics, Inc. (NASDAQ: PTCT) announced that two abstracts have been accepted for the 10th European Pediatric Neurology Society Congress (EPNS) in Brussels, Belgium, on September 25-28.

- Design of a confirmatory phase 3, multicenter, randomized, double-blind, placebo-controlled study of ataluren in patients with nonsense mutation Duchenne muscular dystrophy;

- Disease-related symptoms and activities of daily living: a novel survey of patients with nonsense mutation Duchenne muscular dystrophy will be presented on Wednesday, September 25, 2013 at 13:30 in the selected poster presentation PP3: Neuromuscular and Movement

In addition, PTC will sponsor a symposium at EPNS titled New perspectives in the management of Duchenne muscular dystrophy on September 25 from 12:30 to 13:30.

ABOUT PTC THERAPEUTICS, INC.

PTC is biopharmaceutical company focused on the discovery and development of orally-administered, proprietary small molecule drugs that target post-transcriptional control processes. While PTC's discovery programs are directed at targets in multiple therapeutic areas, PTC is focusing particularly on the development and commercialization of treatments for orphan and ultra-orphan disorders. Post-transcriptional control processes regulate the rate and timing of protein production and are essential to proper cellular function. PTC's internally-discovered pipeline addresses multiple therapeutic areas, including neuromuscular disorders, oncology and infectious diseases. For more information on the company, please visit our website www.ptcbio.com.

FOR MORE INFORMATION PLEASE CONTACT

Jane Baj

+1 (908) 912-9167

jbaj@ptcbio.com

FORWARD LOOKING STATEMENTS:

Any statements in this press release about future expectations, plans and prospects for the Company, the development of and potential market for the Company's product candidates and other statements containing the words "anticipate," "believe," "estimate," "expect," "intend," "may," "plan" "predict," "project," "target," "potential," "will," "would," "could," "should," "continue," and similar expressions, constitute forward-looking statements within the meaning of The Private Securities Litigation Reform Act of 1995. Forward-looking statements involve substantial risks and uncertainties that could cause our future results, performance or achievements to differ significantly from those expressed or implied by these forward-looking statements. Such risks and uncertainties include, among others, those related to the initiation and conduct of clinical trials, availability of data from clinical trials, expectations for regulatory approvals, our scientific approach and general development progress, the availability or commercial potential of our product candidates and other factors discussed in the "Risk Factors" section of the final prospectus for our initial public offering, which is on file with the Securities and Exchange Commission. In addition, the forward-looking statements included in this press release represent the Company's views only as of the date of this release. The Company anticipates that subsequent events and developments will cause the Company's views to change. However, while the Company may elect to update these forward-looking statements at some point in the future, the Company specifically disclaims any obligation to do so. These forward-looking statements should not be relied upon as representing the Company's views as of any date subsequent to the date of this release.