PTC Therapeutics


PTC achieved historic breakthroughs in treating the rare disease Duchenne muscular dystrophy in 2003, and has continued to grow and evolve ever since. Through strategic acquisitions and unparalleled scientific research, our team of “brilliant minds” is “measured by moments” brought to patients and caregivers who face rare disease challenges like Duchenne, aromatic L-amino acid decarboxylase (AADC) deficiency, Huntington’s disease, spinal muscular atrophy and many more.

About PTC Therapeutics, Inc.

PTC is a science-driven, global biopharmaceutical company focused on the discovery, development and commercialization of clinically differentiated medicines that provide benefits to patients with rare disorders. PTC's ability to globally commercialize products is the foundation that drives investment in a robust pipeline of transformative medicines and our mission to provide access to best-in-class treatments for patients who have an unmet medical need.

How Is PTC Working to Treat AADC Deficiency?

PTC is working on an investigational gene therapy utilizing adenovirus vectors to introduce normal dopa decarboxylase (DDC) genes into the body. Called PTC-AADC, this one-time gene therapy treatment supports production of key neurotransmitters.

PTC Preparing to Launch Gene Therapy, Pending Approval


PTC Therapeutics is preparing to launch PTC-AADC, its experimental gene therapy for aromatic l-amino acid decarboxylase (AADC) deficiency, the company has announced in a press release.

Among other launch efforts, the company is expanding its genetic testing program, while finding and preparing expert pediatric neurosurgical centers.

PTC-AADC is designed to provide nerve cells with a working copy of the DDC gene, increasing production of AADC and potentially reverting patients’ symptoms.

A modified and harmless adeno-associated virus carries the therapeutic gene into cells, where it integrates into the genome to become a regular part of each patient’s complete set of genes. The permanent nature of this change makes PTC-AADC a one-time therapy.

To ensure that the treatment reaches the cells where it is needed, PTC-AADC is surgically injected into the putamen, a brain region responsible for producing most of the dopamine in the brain.

PTC-AADC is currently being reviewed by the European Medicines Agency for the treatment of AADC deficiency. A final recommendation from the agency’s Committee for Medicinal Products for Human Use, and the submission of a similar application to the U.S. Food and Drug Administration, are both expected by the first half of 2021.

Of note, the committee’s recommendations are usually followed by the European Commission, which makes the final decision.

The submissions are supported by data from three open-label clinical trials (NCT01395641NCT02926066, and NCT02852213) testing PTC-AADC in children with AADC deficiency, ages 21 months to 8.5 years. Outcomes of 26 patients with AADC deficiency have been evaluated across three separate clinical trials, making it the most comprehensive analysis of patients treated with PTCAADC to date. 

Free Blood Tests; 3-o methyldopa 

The AADC Trust suggested the 3-o MD blood test as a method of diagnosis to a doctor in Taiwan to use to validate it's efficacy as a diagnosis tool for AADCd. Over the years more reserach has been done and now a spot blood test for 3-o MD is available. 

PTC Therapeutics has launched a program to deliver, this blood test, free of charge, so that can help diagnose aromatic L-amino acid decarboxylase.

In people with AADC deficiency, L-dopa instead tends to build up — although this molecule is usually not detectable in blood. However, another molecule called 3-O-methyldopa (3-OMD) tends to also build up when there are high L-dopa levels. Therefore, measuring levels of 3-OMD in the blood can help identify people with AADC deficiency.

“We know that there are a large number of patients with AADC deficiency that have yet to be properly diagnosed,” Stuart W. Peltz, PhD, the CEO at PTC Therapeutics, said in a press release.

“For many AADC deficiency patients and their families, the journey to diagnosis is extremely challenging. Many patients spend years without a diagnosis or are misdiagnosed with other neurological conditions, such as cerebral palsy. We are very proud to provide diagnostic testing — at no cost to the AADC deficiency community — to support accurate and earlier diagnosis for patients,” Peltz added.

The blood test can be done quite simply. Thus, the idea is that people with high 3-OMD levels measured by the blood test could then be referred for subsequent additional testing, ultimately facilitating faster diagnoses of AADC deficiency.

The test can be ordered from PTC by health professionals who believe someone they are treating may have AADC deficiency.

Keith Hyland 

Vice President, Medical Neurogenetics Atlanta 

Rare Resolve for Rare Disease PTC

Rare Resolve for Rare Disease is a PTC education campaign aimed at raising awareness of aromatic l-amino acid decarboxylase (AADC) deficiency, and accelerating the recognition, referral and diagnosis of patients with this rare disease. The campaign objective is to educate, equip and motivate healthcare professionals (HCPs) such as pediatricians and neurologists, as well as parents / caregivers searching for a diagnosis.

While there is currently no cure for AADC deficiency, supportive therapies can be initiated upon diagnosis. PTC has submitted a Marketing Authorization Application (MAA) with the European Medicines Agency (EMA) for its gene therapy in AADC-d.

PTC’s Therapeutic Area Lead, Global Gene Therapy Greg Fuest explains the unmet medical need that drove this initiative:

“Due to the rarity of the disease there is an overall lack of knowledge and awareness among the medical and patient communities.  AADC deficiency is among the most complicated of all neurotransmitter disorders, with symptoms that vary from child to child and can mimic many of the common symptoms attributed to a number of other conditions, such as Cerebral Palsy (CP) and epilepsy. Due to overlapping symptoms, Healthcare Professionals may not recognize AADC-d and not request a genetic test or screening.

“This results in delayed diagnosis and misdiagnosis which is evident by the wide age range at diagnosis from two months to 23 years old. Patients and their loved ones spend years searching for a diagnosis or living with a misdiagnosis, sadly in some cases a correct diagnosis is never reached.

“Furthermore, Initial testing for AADC deficiency has previously typically involved an analysis of cerebrospinal fluid, taken via a lumbar puncture, also known as a spinal tap. A procedure that is invasive, painful and can cause problems post-administration.”


PTC invested in this initiative to address the lack of awareness and education gaps among key stakeholders in order to accelerate recognition, referral and diagnosis of AADC deficiency.


Rare Resolve for Rare Disease includes:

  • Educational websites for Healthcare Professionals,, and for caregivers, – both reaching over 25,000 visitors, to date.

  • Masterclass webinars led by neurology and gene therapy experts, educating more than 400 Healthcare Professionals from over 27 countries.

  • PTC’s global Diagnostics program offering no-cost genetic testing for Healthcare Professionals to test patients suspected of AADC deficiency.

  • Social media outreach to Healthcare Professionals and caregivers with disease awareness and resource sharing.

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