Recurrent mutations in P- and T-proteins of the glycine cleavage complex and a novel T-protein mutation (N1451): A strategy for the molecular investigation of patients with nonketotic hyperglycinemia (NKH)

Screening a DNA bank from 50 patients with enzymatic confirmation of their diagnosis of nonketotic hyperglycinemia gave allele frequencies of 5% for R 515S of P-protein (glycine decarboxylase) and 7% for R320H of T-protein (am inomethyltransferase). In a previous report we found that 3% of the same pa tient alleles were positive for T-protein IVS7-1G>A. In total, testing for these three mutations identified 15% of alleles and positive results (one o r two mutations) were found in 11 of the 50 patients. In addition, a novel point mutation in T-protein, N145I, was found in a single case and a PCR/re striction enzyme assay was developed for its detection. (C) 2001 Academic P ress.