Symptomatic dystrophinopathies in female children.

Although manifesting female carriers of dystrophinopathies have been documented in adults, there are few reports of females presenting with symptomatic dystrophinopathies during childhood. The Canadian Pediatric Neuromuscular Group identified and characterized nine cases of female children 16 years or younger with genetically and/or histologically confirmed symptomatic dystrophinopathy, with an age range of 2-10 years at presentation. Presenting symptoms included proximal muscle weakness (6/9), calf pseudohypertrophy (5/9), abnormal gait (5/9) and myalgias (5/9). Five patients were noted to have significant behavioural and learning issues. The patients had a delay in diagnosis of 4 years from symptom onset. Skewed X inactivation was noted in 5/9 patients, while one patient had X inactivation levels in the normal range. Two of the patients were found to have X/autosome translocation, one of whom also had skewed X-inactivation. Increased awareness of manifesting females with dystrophinopathies will allow for earlier diagnosis and appropriate management for this rare group of patients.