Fears over new wave of vCJD deaths
Sensitivity to vCJD, the human form of mad cow disease (BSE) is determined by many factors. One of these is a genetic polymorphism at codon 129 of the human prion gene PrP. Individuals may have either a methionine (M) or valine (V) codon at this position. People who are heterozygous at this codon, that is, have different codons on each of the two alleles (copies) of the PrP gene in every cell, show resistance to sporadic CJD as well as to acquired prion diseases such as kuru and vCJD. The extent of the resistance is such that to date, all of the 162 known victims of vCJD have been homozygous at codon 129, and all have had two methionine codons (genotype 129MM).
Until now.
The first reported case of vCJD involving a victim who is homozygous for valine (129VV) at codon 129 has just been published. Why does that matter? It’s too early to say for sure, but this cases raises the possibility of a new wave of human vCJD cases with a longer incubation period in the 10% of the population with the 129VV phenotype, in addition to the previously at risk 30-40% of the population with the 129MM phenotype.
Related:
- Creutzfeldt-Jakob Disease, Prion Protein Gene Codon 129VV, and a Novel PrPSc Type in a Young British Woman
- Prion Disease Update
Tags: Biology, Genetics, Health, Medicine, Microbiology, Prions, Science
