New mutation in the myophosphorylase gene (Asn684Tyr) in a Spanish patientwith McArdle's disease

We have identified a novel missense mutation, an A-T transition at codon 68 4 in exon 17, changing an encoded asparagine to a tyrosine (Asn684Tyr) in a Spanish patient with typical McArdle's disease. The patient was a compound heterozygote, with a previously-described mutation (Gly204Ser) on the othe r allele. This report expands the molecular genetic heterogeneity in McArdl e's disease, emphasizes the presence of private mutations in specific ethni c groups, and indicates that geographic origin must be considered before un dertaking DNA analysis for diagnosis. (C) 1999 Elsevier Science B.V. All ri ghts reserved.