Genotype-phenotype correlations in phenylketonuria.

Genotyping of the phenylalanine hydroxylating system offers a new way of characterizing patients with phenylalanine hydroxylase (PAH) deficiency. This paper investigates the power of genotyping as a parameter for differential diagnosis and as a measure of the risk factor of brain damage in well-treated patients with phenylketonuria (PKU). Thirty-three PKU patients were followed up over 9 years and the quality of dietary treatment, plasma phenylalanine (phe) in the newborn period before treatment and intellectual outcome at the age of 9 years were measured and correlated with the predicted residual activity (PRA) of the phe hydroxylase system as estimated from mutation analysis of the PAH gene.

Identification of a new missense mutation in Japanese phenylketonuric patients.

A new missense mutation in the phenylalanine hydroxylase (PAH) gene was identified in 20/30 members of the families of 10 unrelated Japanese phenylketonuria (PKU) patients from Kyushu island. The point mutation was present in 20 of 40 mutant alleles. This was proved by DNA sequence analysis after polymerase chain reaction (PCR) amplification and allele-specific oligonucleotide (ASO) hybridization.