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

The clinical similarity with the X-linked muscular dystrophies and the uniqueness of the homology between the DMD-like and the 1.8 kb sequences 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 analysis excluded linkage with MYB (6q22-23) and ESR (6q24-q27) at 8 = 0.10 and with TCP1 (6q25-q27) at 0 = 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.