PrP genotypes of captive and free-ranging Rocky Mountain elk (Cervus elaphus nelsoni) with chronic wasting disease

The PrP gene encodes the putative causative agent of the transmissible spon giform encephalopathies (TSEs), a heterogeneous group of fatal, neurodegene rative disorders including human Creutzfeldt-Jakob disease, bovine spongifo rm encephalopathy, ovine scrapie and chronic wasting disease (CWD) of North American deer and elk. Polymorphisms in the PrP gene are associated with v ariations in relative susceptibility, pathological lesion patterns, incubat ion times and clinical course of TSEs of humans, mice and sheep. Sequence a nalysis of the PrP gene from Rocky Mountain elk showed only one amino acid change (Met to Leu at cervid codon 132), Homozygosity for Met at the corres ponding polymorphic site (Met to Val) in humans (human codon 129) predispos es exposed individuals to some forms of Creutzfeldt-Jakob disease. In this study, Rocky Mountain elk homozygous for PrP codon 132 Met were over-repres ented in both free-ranging and farm-raised CWD-affected elk when compared t o unaffected control groups.