In fact, the likely incubation periods in men, who only took part in funeral feasts when they were young children, may have ranged from 39 to 56 years, or perhaps even up to 63 years, the investigators wrote.
They also looked for evidence of a specific polymorphism, or variant, in the prion protein gene in humans that has been shown to be a major determinant of susceptibility to prion diseases. The polymorphism, which occurs at codon 129 of the gene PRNP, determines whether the amino acids methionine or valine are present at that location.
All cases of human vCJD have occurred in patients with the methionine-methionine genotype, which suggests that the methionine-valine and valine-valine genotypes are protective, researchers have found.
They found that eight of the 10 patients for whom genetic data were available were heterozygous for the polymorphism, a genotype associated with extended incubation periods and resistance to prion disease, the authors found.