EP.65Normal respiratory function in a young adult with Duchenne muscular dystrophy – the possible role of supplements

Abstract

Idebenone has been shown to stabilize lung function in Duchenne muscular dystrophy (DMD) boys who are steroid naïve when given over 12 months. An ongoing clinical trial is currently running in DMD on steroids. We present a non-ambulant DMD, whose parents self-prescribed Idebenone and flavonoid-based supplement from the age of 13.5 and 14 respectively, since that time he has maintained normal lung function at 17 years, with no evidence of decline: Forced Vital Capacity (FVC) was 3.08 litres (98% corrected for height) and peak cough flow was 324l/min. Dystrophin analysis showed duplication exons 18-30. Intermittent prednisolone (0.7mg/kg) was started at 9 years then switched to daily deflazacort (0.46 mg/dl) at 11.5 years and maintained at a stable dose ever since. Loss of ambulation occurred at 13 years. At 13.5 years, the patient was diagnosed with pubertal delay and glucose intolerance and Metformin 250 mg twice/day and testosterone IM 25 mg monthly were started. At the same age, idebenone 400 mg daily was administered and six months later an oral flavonoid-based supplement was added. His lung function at that age was beyond expected with FVC 2.66 litres (108%) and a sleep study excluded sleep disordered breathing. Despite the progressive motor function deterioration and the reduction of steroids dose per weight, this patient has maintained, over time, normal respiratory function both in terms of lung volumes and in terms of good airway clearance and absence of respiratory infections. Moreover, his latest sleep study at the age of 17 showed a normal gas exchange and absence of any upper airway obstruction. This report highlights the need for careful review of all the medications DMD patients are taking, particularly supplements commonly available over the counter that can impact on some disease features. This will be relevant both during the regular follow up assessments and during the screening phase of clinical trials.