Characterisation of a large, single-centre cohort of patients with Becker muscular dystrophy to inform standardised care guidelines

Aims: This retrospective, cross-sectional study aimed to characterise a large cohort of paediatric and adult patients with Becker muscular dystrophy (BMD) to inform clinical care. Results: The analysis included data from 163 male patients with genetically confirmed BMD followed up at a highly specialised neuromuscular centre between 1982 and 2023. The mean age at last neuromuscular assessment was 33.2 years (range 1.4–86.3). Large deletions in the DMD gene were the most common variants (78% of cases), followed by large duplications and small variants, each accounting for 11% of cases. BMD diagnosis was prompted by skeletal muscle symptoms in 52.2% of cases, a positive family history in 27.6%, neuropsychiatric issues or diagnoses in 9.7%, incidental findings in 6.7%, and cardiomyopathy in 3.8%. Twenty-three percent of patients were non-ambulant at last evaluation, with a mean age at loss of ambulation (LoA) of 42.2 years (range 11.2–77.6 years). Disease duration correlated with the severity of motor impairment (expressed as fully ambulant, ambulant with limitation, ambulant with aids, non-ambulant) at last assessment. Cardiac involvement was observed in 52.3% of patients. Severe respiratory impairment was rare and more prevalent in non-ambulant patients. Neuropsychiatric issues were common (44.2%), but only 18.4% of patients had a formal diagnosis. Conclusions: Retrospective analyses of clinical case records contribute to improved understanding of the variability of phenotypes of BMD. Combined with data from other large cohorts, these findings can contribute to the development of standard of care guidelines for BMD and inform the design of clinical trials of novel therapies.