Polymorphic microsatellite sites in the PRNP region point to excess of homozygotes in Creutzfeldt–Jakob disease patients

Polymorphic microsatellite sites within 148 kb of the human prion gene complex, including the genes PRNP, PRND and PRNT, were analysed together with the Codon129 variants regarding 50 CJD (Creutzfeldt–Jakob Disease) patients and 46 non-diseased control persons. Three of the sites (MM03, MM04, Codon129) differed significantly (P < 0.05) for their allele frequencies between the two groups — the predominant allele being always more frequent in the CJD group. Deviations from Hardy–Weinberg Equilibrium were mainly obtained in the CJD group — in all cases with a reduction of the observed heterozygosity. The sites MM03, MM04 and Codon129 were also analysed for their haplotypes. The predominant homozygous haplotype combination was more frequently observed in the CJD group (0.875) than in the non-diseased group (0.38). Thus the different polymorphic sites indicate that high CJD disposition is associated with homozygosity in the PRNP gene.