Linkage analysis in families with autosomal recessive limb‐girdle muscular dystrophy (LGMD) and 6q probes flanking the dystrophin‐related sequence

Abstract

The clinical similarity with the X‐linked muscular dystrophies and the uniqueness of the homology between the DMD‐like and the 1.8 kb sequeces at the carboxyterminal domain of the dystrophin gene led to the suggestion that this 6q sequence might be a strong candidate for one of the autosomal recessive muscular dystrophies. Thus, we tested, through linkage analysis, if 6q probes flanking the dystrophin‐homologous sequence are linked to the gene responsible for limb‐girdle dystrophy (LGMD). A total of 226 individuals (57 patients and 169 unaffected relatives) from 19 large unrelated Brazilian families was studied. Results of two‐point aalysis excluded linkage with MYB (6q22–23) and ESR (6q24–q27) at θ=0.10 and with TCP1 (6q25–q27) at θ=0.05, indicating that the LGMD gene is not in the 6q23–q27 region. Therefore, the dystrophin‐homologue sequence is not the gene responsible for LGMD.