Prion Diseases as Transmissible Zoonotic Diseases

Lee, Jeongmin; Kim, Su Yeon; Hwang, Kyu Jam; Ju, Young Ran; Woo, Hee-Jong

Meanwhile, many studies have sought to identify the association between specific genotypes and the occurrence of the disease; a correlation between vCJD and methionine homozygote (MM type) at codon 129 in the human prion suggests that the MM type is highly related and susceptible to prion infection [51] , and is clearly documented as a significant genetic risk factor [52] . A study on kuru among cannibal tribes shows that the incubation period of prion diseases differs among individuals based on genotype [53] . The MM type at codon 129 of the prion is most common in Korean people and has the shortest incubation period, with death following shortly after disease development; the methionineevaline heterozygote (MV type) appears to be most resistant to the disease, and a case with 40 years of incubation has also been reported. At present, all vCJD patients in Europe (including patients affected through transfusion [54] ) have the MM type except for one case [55] . Therefore, Aguzzi at University Hospital of Zurich in Switzerland warns that patients should be observed for at least 40 years since the number of patients with the MV type may increase in the future. The Spongiform Encephalopathy Advisory Committee appointed by ministers from the UK assumes that there may be 4000e10000 infected persons with no symptoms in the UK; however, valine homozygote-(VV type) or MVtype patients may die of different causes due to the long incubation period after they have been exposed to the pathogenic prion.