Some human genotypes more prone to variant Creutzfeldt-Jakob disease

Reported by Susan Aldridge, PhD, medical journalist

An analysis of tissue from patients with variant Creutzfeldt-Jakob disease suggest the existence of a new genotype susceptible to the disease.
Variant Creutzfeldt-Jakob disease (vCJD) is a rare, and fatal, brain disorder, which emerged in Britain several years ago. It is generally accepted to be the human form of 'mad cow' disease and is linked to consumption of infected beef. So far there have been only 161 definite or probable cases, but there have been fears that more cases may emerge over time.

According to a new study from the University of Edinburgh, genetic influences may be more important than previously thought in susceptibility to vCJD. So far, only people with one genetic make-up (genotype) called MM have contracted the disease. But the scientists may have identified a second susceptible human genotype, called VV. They carried out DNA analysis on appendix tissue from two individuals which harbored prion protein - a marker of vCJD infection. Both tissue samples proved to be of the VV genotype, which suggests that this population group could be susceptible to the disease. The concern is that there could be other cases to emerge because this could be a variant of the disease with a longer incubation period. However, there was no evidence that the two individuals in this study had clinical signs of vCJD nor that they were infectious to others. It is hard to draw firm conclusions from only two cases, but the study highlights the need for ongoing surveillance of vCJD in the UK.

Source
British Medical Journal 20th May 2006 Volume 332 pages 1186-1188

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