Patient case (clinical description): An 8-year-old boy is brought to the clinic by his parents because of weakness and difficulty of standing up from a sitting position. The mother is healthy but had a brother who died in his 20th after being disabled and using wheelchairs in the last few years of his life. Physical examination shows 3/5 lower extremity muscle strength and enlarged calf muscles. The other physical examination and vital signs are unremarkable. Muscle biopsy showed absence of dystrophin protein. The patient is diagnosed with DMD.

Patient's own account: I brought my  8-year-old son to the doctor's clinic. He was struggling to stand up from a chair for the past few days. My wife is healthy but she was pretty worried since his brother died in his 20s after being disabled and using a wheelchair for the last years of his life. The doctor did an exam which highlighted weakness in the leg muscles and unusually large calf muscles. The rest of the exam was fine, and his vitals were normal. My son did a muscle biopsy, and it showed that the protein important for muscle strength and function is missing. The doctor diagnosed him with Duchenne muscular dystrophy.

Clinical trial: A Study to Assess Dystrophin Levels in Participants With Nonsense Mutation Duchenne Muscular Dystrophy (nmDMD) Who Have Been Treated With Ataluren

Eligibility criteria:
Inclusion Criteria:

          -  Evidence of signed and dated informed consent/assent document(s) indicating that the
             participant (and/or his parent/legal guardian) has been informed of all pertinent
             aspects of the trial.

          -  Ambulatory (10 meters walk/run in less than [<] 30 seconds) and functional grade on
             the Brooke Upper Extremity Scale of a 1 or a 2.

          -  Currently being treated with ataluren 10, 10, 20 mg/kg for >=9 months, with no gap in
             treatment of greater than (>) 1 month, in an ongoing PTC-sponsored nmDMD clinical
             trial prior to study entry.

          -  Phenotypic evidence of duchenne muscular dystrophy (DMD) based on the onset of
             characteristic clinical symptoms or signs (for example, proximal muscle weakness,
             waddling gait, and Gowers' maneuver) by 6 years of age and an elevated serum creatine
             kinase (CK). Medical documentation of phenotypic evidence of DMD needs to be provided
             upon request by the medical monitor.

          -  Willing to undergo muscle biopsy.

        Exclusion Criteria:

          -  Known contra-indication to muscle biopsy (such as bleeding or clotting disorders).

          -  Exposure to another investigational drug within 2 months prior to study enrollment or
             ongoing participation in any non-ataluren interventional clinical trial.

          -  Requirement for daytime ventilator assistance or any use of invasive mechanical
             ventilation via tracheostomy. Note: Evening non-invasive mechanical ventilation such
             as use of bilevel positive airway pressure (Bi-PAP) therapy is allowed.

          -  Prior or ongoing medical condition (for example, concomitant illness, psychiatric
             condition, behavioral disorder), medical history, physical findings or laboratory
             abnormality that, in the investigator's opinion, could adversely affect the safety of
             the participant, makes it unlikely that the course of treatment or follow-up would be
             completed, or could impair the assessment of study results.
Male
No healthy subjects accepted to join the trial.



Eligibility (NLI label): Entailment