Spontaneous mutations in the prion protein gene causing transmissible spongiform encephalopathy.

We analyzed the prion protein gene (PRNP) region in patients with transmissible spongiform encephalopathy associated with the PRNP D178N mutation. The results suggest that the D178N chromosomes had independent origins in each affected pedigree or apparently sporadic case. A de novo spontaneous PRNP mutation was observed. We provide evidence that hereditary and apparently sporadic transmissible spongiform encephalopathy cases associated with the D178N mutation result from multiple recurrent mutational events.