DISTRIBUTIONS OF PHENYLALANINE-HYDROXYLASE MUTATIONS AND HAPLOTYPES IN LITHUANIAN PHENYLKETONURIA PATIENTS

The distribution of phenylketonuria (PKU) mutations and haplotypes was studied in a sample of 50 families with at least one PKU child detect ed through the Lithuanian neonatal screening program from 1975 to 1992 . Mutations were identified on 84 of the 100 alleles. Three mutations (R408W, R158Q, R261Q) together accounted for 78% of all chromosomes st udied. The mutations IVS12nt1, IVS10nt546, 6272X, Q232Q were very rare . Nine different DNA haplotypes based on restriction fragment length p olymorphisms at the phenylalanine hydroxylase locus were observed. The frequency of the mutant R408W is one of the highest in Europe, Most o f the PKU patients were compound heterozygotes, and 47% were homozygot es for the mutations identified in this series.