Manifesting carrier of x-linked Duchenne muscular dystrophy

The authors have investigated the uncommon occurrence of a boy affected with Duchenne muscular dystrophy (DMD) whose mother showed myopathic features in the clinical history, EMG, biochemical tests and muscle biopsy. This study suggests that the patient's mother is a manifesting carrier of X-linked DMD with clinical, neurophysiological, biochemical and histological findings of X-linked DMD with an almost complete inactivation of the paternal X-chromosome (lyonization).