A MOLECULAR SURVEY OF PHENYLKETONURIA IN ICELAND - IDENTIFICATION OF A FOUNDING MUTATION AND EVIDENCE OF PREDOMINANT NORSE SETTLEMENT

Iceland was settled during the late 9th and early 10th centuries AD by Vikings who arrived from Norway and the British Isles, Although it is generally acknowledged that the Vikings brought with them Celtic slav es, the relative contribution of these peoples to the modern Icelandic gene pool has been a matter of considerable discussion, Most populati on genetic studies using classical markers have indicated a large Iris h genetic contribution, We have investigated the molecular basis of ph enylketonuria (PKU) in 17 Icelandic patients and found 9 different mut ations in the phenylalanine hydroxylase gene. One novel mutation, Y377 fsde1T, accounts for more than 40% of the mutant chromosomes. Haplotyp e data support a common ancestral origin of the mutation, and genealog ical examination extending back more than 5 generations shows that thi s mutation has probably arisen in an isolated part of southern Iceland and was enriched by a founder effect, At least 7 PKU mutations have o rignated outside iceland, The almost exclusively Scandinavian backgrou nd of these mutations and the complete absence of common Irish PKU mut ations strongly support historical and linguistic evidence of a predom inant Scandinavian heritage of the Icelandic people.