Becker muscular dystrophy (BMD) is caused by a dystrophin missense mutation in the original family of Becker and Kiener.

Becker muscular dystrophy, BMD (#300,324) was first described by Becker and Kiener in 1955 and later recognised as a clinically milder allelic form of Duchenne muscular dystrophy (DMD). In muscle biopsies, BMD is characterized by the residual expression of dystrophin protein resulting in an apparently partial function. The mutations underlying BMD belong to the milder end of the wide spectrum of dystrophin mutations. We had the opportunity to study the mutation in a recent offspring of the original family of Becker and Kiener and identified a single amino acid substitution in exon 3 of the dystrophin gene: c.136G>T, p.(Asp46Tyr), a missense mutation which has already been described in another BMD family from Italy.