Becker muscular dystrophy with onset after 60 years

We report an unusual example of Becker muscular dystrophy in which the patient was asymptomatic until his mid-60s, and diagnosis was not made until he was 67 years old. The patient had the unusual deletion of exons 3 to 9 within an actin-binding region of the dystrophin gene, removal or disruption of which is almost invariably associated with a more severe clinical phenotype. Our case illustrates the danger of drawing conclusions about possibly symptomatic deletions without lifelong follow-up.