ClinVar

In a Norwegian patient with phenylketonuria (PKU; 261600), Eiken et al. (1992) identified a novel mutation in exon 12 in association with haplotype 12 alleles, by use of SSCP analyses. A patient who was homozygous for the arg408-to-gln (R408Q) mutation exhibited a mild PKU variant. Eiken et al. (1992) mapped the district of origin of the R408Q and phe299-to-cys (F299C; 612349.0039) mutations by determining the birthplaces of the relevant grandparents. In contrast to both the overall distribution of PKU mutations and the general population density in Norway, the ancestors of these 2 mutations appeared to be restricted to the western and northern coastal districts. See 612349.0042.

In Chinese, Lin et al. (1992) found a G-to-A transition in codon 408 as the basis of phenylketonuria. The missense mutation resulted in the substitution of arginine for glutamine and accounted for about 5% of PKU chromosomes among Chinese. The mutation was in linkage disequilibrium with RFLP haplotype 4. The arg408-to-trp mutation (R408W; 612349.0002) is in the same codon.