Polymorphism of PRNP codons in the normal Icelandic population

OBJECTIVES: Polymorphisms in the prion protein gene in humans influence susceptibility to, and phenotype of, prion diseases. Methionine-methionine (MM) homozygosity at codon 129 is a risk factor for sporadic Creutzfeldt-Jakob disease (CJD). Polymorphism at codon 117 and changes in the octapeptide repeat region have been associated with genetic CJD. Knowledge of genetic background in normal populations may contribute to better understanding of prion diseases. MATERIALS AND METHODS: Polymorphism at codon 129, codon 117 and deletions of octapetide repeats were studied in 208 healthy blood donors of both genders and of different age. RESULTS: Polymorphism at codon 129 was: MM 46.6%, methionine-valine 44.7%, valine-valine 8.7%. Polymorphism at codon 117 was observed in 4.8%. Deletions of octapeptide repeats were not detected. There were no gender or age differences in the distribution of codon 129 polymorphism. The frequency of codon 129 polymorphisms was, with one exception, not significantly different from that observed elsewhere in Europe.