Novel mutation linked to mad cow disease
Researchers from the United States Department of Agriculture have identified a novel mutation in the bovine prion protein gene in a cow confirmed with atypical Bovine Spongiform Encephalopathy (BSE). This is the first report of a confirmed case of BSE (aka mad cow disease) with a potential pathogenic mutation within the bovine Prnp gene. BSE, a transmissible spongiform encephalopathy (TSE) or prion disease of cattle, was first discovered in the United Kingdom in 1986. BSE is considered to be the cause of a human prion disease known as variant Creutzfeldt-Jakob Disease (vCJD). Veterinary scientists have now identified a novel mutation, E211K, in the bovine Prnp gene. This mutation is identical to the E200K pathogenic mutation in the human Prnp, which has been described as the most common cause of genetic CJD. The study supports the view that all three etiological forms of TSEs in humans are also present in cattle: infectious, sporadic, and genetic. It further supports the hypothesis that the BSE epidemic may have originated from a genetic case of cattle BSE. Cattle with similar mutations can be expected in cattle herds world-wide and could be the source of new BSE outbreaks. It is therefore critical to continue world-wide surveillance for typical and atypical BSE cases including sequencing of the Prnp gene. A newly developed assay system for detecting the E211K mutation has been developed for this purpose. Finally, in order to protect humans it is essential to continue to exclude Specified Risk Materials from the food chain and to maintain the ruminant feed ban.
BSE Case Associated with Prion Protein Gene Mutation. PLoS Pathog 4(9): e1000156
Bovine spongiform encephalopathy (BSE) is a transmissible spongiform encephalopathy (TSE) of cattle and was first detected in 1986 in the United Kingdom. It is the most likely cause of variant Creutzfeldt-Jakob disease (CJD) in humans. The origin of BSE remains an enigma. Here we report an H-type BSE case associated with the novel mutation E211K within the prion protein gene (Prnp). Sequence analysis revealed that the animal with H-type BSE was heterozygous at Prnp nucleotides 631 through 633. An identical pathogenic mutation at the homologous codon position (E200K) in the human Prnp has been described as the most common cause of genetic CJD. This finding represents the first report of a confirmed case of BSE with a potential pathogenic mutation within the bovine Prnp gene. A recent epidemiological study revealed that the K211 allele was not detected in 6062 cattle from commercial beef processing plants and 42 cattle breeds, indicating an extremely low prevalence of the E211K variant (less than 1 in 2000) in cattle. We hypothesize that the bovine Prnp E211K mutation most likely has caused BSE in the approximately 10-year-old cow carrying the E221K mutation.
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Tags: Agriculture, Biology, Emerging disease, Food, Genetics, Health, Medicine, Microbiology, Prions, Science
