GENETIC-ANALYSIS OF JAPANESE PATIENTS WITH MYOPHOSPHORYLASE DEFICIENCY (MCARDLES-DISEASE) - SINGLE-CODON DELETION IN EXON-17 IS THE PREDOMINANT MUTATION

We report molecular genetic analysis of 11 Japanese patients with myop hosphorylase deficiency (McArdle's disease). Four reported mutations, frequently observed in patients with McArdle's disease, in exons 1, 5, 14 and 17 were investigated. Seven patients out of 11 were homozygous for a single-codon deletion at codon 708/709 in exon 17 and one patie nt was heterozygous for a single-codon deletion with an unknown mutant allele. In contrast, the predominant mutation reported in US and UK p atients (CGA to TGA at codon 49 in exon 1), accounting for 75% and 83% of the cases, respectively, was not found in any of the Japanese pati ents. Results suggest that the predominant mutation in Japanese patien ts is a single-codon deletion at codon 708/709 in exon 17 (found in 73 % of our patients) and differs from the most common mutation in US or UK patients.