MOLECULAR-GENETIC STUDIES IN MUSCLE PHOSPHOGLYCERATE MUTASE (PGAM-M) DEFICIENCY

Phosphoglycerate mutase (PGAM; EC 2.7.5.3) catalyzes the interconversi on of 2-phosphoglycerate and 3-phosphoglycerate in the glycolytic path way. Hereditary muscle PGAM deficiency has been identified in 9 patien ts with myopathy, All patients had exercise intolerance and 6 had myog lobinuria. Seven of the 9 patients were African-Americans: 5 of them w ere homozygous for a nonsense mutation, TGG(Trp) to TAG at codon 78; 1 was a compound heterozygote for the nonsense mutation and a missense mutation, GAG(Glu) to GCG(Ala) at codon 89; and 1 could not be tested. The only 2 Caucasian patients, a brother and sister, were homozygous for a different missense mutation, CGG(Arg) to TGG(Trp) at codon 90. D espite the small number of patients identified, these findings indicat e that there is a common mutation in African-Americans white there may be molecular genetic heterogeneity in other ethnic groups. (C) 1995 J ohn Wiley and Sons, Inc.