Creutzfeldt-Jakob disease profile in patients homozygous for the PRNP E200K mutation

We identified 70 Creutzfeldt-Jakob disease patients with the previously des cribed E200K mutation in the prion protein gene. The purpose of this study was to define the clinical features of E200K homozygous patients (n = 5), c ompared with heterozygotes. We found a statistically significant younger ag e at disease onset for the homozygous patients, although the average age at onset in this group was still in midlife. Disease features were not statis tically different in the two groups. Possible explanations are discussed.