A new dysferlin gene mutation in two Japanese families with limb-girdle muscular dystrophy 2B and Miyoshi myopathy

We found a new dysferlin gene mutation in two Japanese families, one with l imb-girdle muscular dystrophy 2B and the other with Miyoshi myopathy. All p atients in the limb-girdle muscular dystrophy 2B family showed apparent pro ximal dominant muscle atrophy and weakness, whereas a patient with Miyoshi myopathy in the second family showed distal muscle involvement at an early stage. The common clinical feature of all patients in both families was pre ferential involvement of calf muscles rather than the tibialis anterior mus cle, which was confirmed by muscle computed tomography scan. All patients i n both families shared the same homozygous alleles for chromosome 2p13 mark ers, and dysferlin gene analysis revealed a novel missense mutation, a G to A transition at nt 5882, which changed aspartic acid to asparagine at codo n 1837. Allele-specific polymerase chain reaction analysis was used for con firmation of the mutation and for genotype analysis of the family members. (C) 2001 Elsevier Science B.V. All rights reserved.