A retrospective natural history study of 943 patients with Becker myopathy (BMD) followed in 17 Italian neuromuscular centres provides information on the correlation between genetic abnormality, symptoms and disease course.
- Diagnosis was made at a median age of 7.5 years (4.0-14.0); the median age at last assessment was 26 years (16.6 – 41.9).
- The first signs of the disease were hyperCKaemia in 54.8% of patients, myalgias or cramps in 12%, difficulty walking in 6.4%, or running (4.4%) and, in a few cases, delayed motor development, dilated cardiomyopathy or behavioural problems.
- For patients with known genetic abnormalities (95.8%), the majority were deletions (85.8%), duplications (5.5%) and small mutations (8.6%). The reading frame was preserved in 86.3% of cases.
- Patients with del45-49 lost their ability to walk slightly earlier (41 years) than those with del45-47 or del45-48 (66.3 and 66 years). Consistent with previous studies, the hearts of patients with del45-55 and del48 appear to be better protected from left ventricular dilatation, resulting in a moderate form of BMD.
- As in DMD, the evolution of BMD also remains under the control of genetic modifiers, which influence its course and complicate the prognosis.
