People of all ages and genotypes could be affected by the prion protein of variant Creutzfeldt-Jakob disease, the human variant of ‘mad cow disease’, reveals a survey published by bmj.com today.
People of all ages and genotypes could be affected by the prion protein of variant Creutzfeldt-Jakob disease, the human variant of ‘mad cow disease’, reveals a survey published by bmj.com today.A team of UK researchers conducted a study to better understand how many people could be carriers of the abnormal prion protein that could lead to variant Creutzfeldt-Jakob disease, vCJD, alongside a study of the genetic makeup, or genotype, of these individuals.
An accompanying editorial questions how widespread CJD is, and highlights that, although it is a relatively rare disease, “infection” is relatively common.
As a result, the researchers say that doctors need to understand the public health measures that are in place to protect patients.
vCJD is a degenerative brain disease that is often called the human form of Bovine spongiform encephalopathy, BSE, or “mad cow disease”, which emerged after there was widespread exposure to BSE in the late 1980s and early 1990s in the UK through contaminated meat products.
However, there are only 177 clinical cases of the disease in the UK to date and previous studies estimated that only 4,000 people may carry the vCJD prions. Today’s research reveals that the estimate could be much higher than originally thought.
Researchers state that there is uncertainty around how many people could develop the disease, and that they are unsure of the risks of transmission through blood transfusion or surgery.
UK health agencies have already introduced a ban preventing those who have received a blood transfusion since the 1980s from donating blood, but this would not include those in the general population who may also carry the vCJD prion protein.
The researchers examined 32,000 anonymous appendix samples from people of all ages who had them removed between the years of 2000 and 2012 at over 41 different hospitals across England. From this, 16 samples tested positive for the abnormal prion protein.
Consequently, these results show that 1 in 2,000 individuals in the UK are likely to be carriers of this abnormal prion protein.
There was no difference between the presence of the prion protein in those born between 1941-1960 and those born during 1961-1985, and no differences between genders were found.
Likewise there was no variation found between the geographical location and the genotype of those individuals.
Genetic testing of the 16 positive samples revealed a higher proportion of valine homozygous genotype on the codon 129 of the gene encoding the prion protein compared with the general UK population, which differs from the 177 patients with vCJD who have all been methionine homozygous genotype.
There is concern that individuals with the valine homozygous genotype may be susceptible to developing the condition over a long incubation period, or they may not even show any clinical signs of the disease.
Researchers stress that the number of patients with clinical vCJD is well below the number suggested by the prevalence of abnormal prion protein, but that it is essential to continue research into tests which can detect the abnormal prion protein in the blood of carriers.
Roland Salmon, author of the accompanying editorial and a retired consultant epidemiologist says that many important questions remain about the characteristics of these diseases and what other animal prion disease may be transmitted to humans.
Source: The Information Daily
