The records of 225 Japanese patients with Becker’s myopathy, with an average age of 31, were examined to gain a better understanding of the natural history of this disease. The results show that :
- muscular dystrophy begins with muscular symptoms, hyperCKemia and central nervous system disorders,
- 53.8% of patients have walking difficulties, with wheelchair use at an average age of 36,
- muscular and respiratory impairment depend on the type of deletion in the DMD gene: very severe for a deletion of exons 45 to 49 or, on the contrary, without the need for ventilation for deletions of exons 45 to 47 or 45 to 55,
- cardiac damage is not associated with the severity of muscle damage associated with DMD gene deletions,
- there is no particular genetic correlation for central nervous system disorders.
