an autopsy found vCJD in a person whose genetic signature is shared by about 50 percent of Caucasians. Previously the disease, which is thought to come from eating beef products from cattle infected with BSE, was believed to affect only people with a genetic profile found in about 35 percent of Caucasians.
]. Peden, et al., "Preclinical vCJD after blood transfusion in a PRNP codon 129 heterozygous patient," The Lancet
364 (7 August 2004) 527-529
Our findings also show that vCJD infection can be confirmed by western blot analysis of PrPres in an individual who is a heterozygote at codon 129 of PRNP. This finding has major implications for future estimations of numbers of vCJD cases in the UK, since individuals with this genotype constitute the largest genetic subgroup in the population. This subgroup might have a different incubation period after exposure to either primary infection by the bovine spongiform encephalopathy (BSE) agent or secondary infection by blood transfusion. A very lengthy incubation period might explain why no clinical cases of vCJD have yet been observed in this subgroup. Such preclinical cases might also represent a source of iatrogenic infection themselves, either by blood donation or by contamination of surgical instruments coming into contact with lymphoid tissues, even in the absence of infectivity in the brain.... It is also possible that the PRNP codon 129 genotype might affect the distribution of PrPres in tissues.
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