The molecular genetics of familial Creutzfeldt-Jakob disease in France.

Five French families with Creutzfeldt-Jakob disease (CJD) were found to have either of 2 different point mutations (at codons 178 and 200) in the amyloid precursor gene (PRNP) on chromosome 20. The ancestry of these and other CJD families outside of France suggests that the codon 178 mutation had a northern European origin, while the codon 200 mutation originated in central Europe and the Mediterranean basin. Evidence is presented that the mutations either cause or predispose to familial forms of CJD, and also influence their phenotypic expression, although considerable clinical and neuropathological heterogeneity may occur between and even within families having the same mutation. Experimental transmission of disease was successful in 4 of 5 inoculated cases, comparable to the transmission rate in sporadic CJD.