COULD a whole new section of the population be at risk of developing the human form of mad cow disease? That is the big question following the discovery of the agent responsible for variant Creutzfeldt-Jakob disease (vCJD) in the appendixes of two people who have a different genetic make-up from all other known victims of the disease.
So far, the UK has recorded 161 cases of vCJD, and all the patients have had the same gene variant for the prion protein that is implicated in the disease: the MM genotype, which is found in 40 per cent of the population. The two infected appendixes, found by a team led by James Ironside of the UK鈥檚 National CJD Surveillance Unit in Edinburgh, were the first from people with the VV form of prion gene, found in 10 per cent of the population.
鈥淭he two people have a different genetic make-up from all known victims鈥�
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The infected organs were identified during a screening programme the team undertook on 11,109 appendixes and 1565 tonsils removed in operations in the UK between 1995 and 2000 (BMJ, vol 332, p 1186). Neither patient is traceable, but no vCJD cases in VV individuals have yet been found, suggesting they remain healthy for now. The vulnerability of the remainder of the population, who have the MV form of the prion, is not known.
