PHENYLKETONURIA IN A LOW INCIDENCE POPULATION - MOLECULAR CHARACTERIZATION OF MUTATIONS IN FINLAND

The incidence of phenylketonuria (PKU) in Finland is extremely low, pr obably below 1 in 100000. We describe the mutations and haplotypes in all four presently known patients. Mutation R408W was found on four mu tant chromosomes (all haplotype 2), and IVS7ntl, R261Q, and IVS2nt1 we re each found on a single chromosome. No mutation was found on the rem aining chromosome. These findings support a pronounced negative founde r effect as the cause of the low incidence of PKU in Finland, and are consistent with existing data regarding the European and Baltic origin of Finnish genes.