Polymorphism of exon 4 of the CANP-3 gene in patients with primary myopathies

The structures of the gene for calpain (CANP-3) and of the DMD gene were an alyzed in patients with primary myopathies [limb-girdle muscular distrophy (LGMD) and Duchenne-Becker myodystrophy (DBM)] from various regions of Russ ia. Via amplification of DNA isolated from the peripheral blood lymphocytes of 74 patients, extended deletions were found in 18 out of 55 patients wit h DBM. In none of the 19 patients with LGMD were extended deletions in the CANP-3 gene found. In most patients with LGMD, the amplification of the pro moter region and exons 1, 2, 3, 4, 5, and 6 of the CANP-3 gene yielded a si ngle product of corresponding length, but in six patients (three sib pairs) , amplification of exon 4 of the CANP-3 gene yielded two products of differ ent size. The following single-strand conformation polymorphism (SSCP) anal ysis revealed a pronounced polymorphism of exon 4 of the CANP-3 gene in 14 out of 19 patients with LGMD. This structure of exon 4 of the CANP-3 gene w as found neither in 16 patients with DBM who had deletions in the DMD gene nor in 16 patients with DBM who had no deletions in the DMD gene.