26 May 2016

The Y chromosome and Alzheimer's disease

The results obtained by an international group of researchers working under the leadership of Professors Lars Forsberg and Jan Dumanski indicate that men whose blood cells do not have a Y chromosome are at increased risk of developing Alzheimer's disease, as well as death from other causes, including among many types of cancer.

The loss of the Y chromosome (LOY, from the English Loss Of Y chromosome) is the most common mutation acquired by men throughout their lives. The frequency of occurrence of this mutation in men over the age of 80 years can reach 20%.

The authors analyzed for the presence of LOY in the leukocytes of more than 3,200 men, whose age ranged from 37 to 96 (average age 73 years). Using standard molecular techniques that detect LOY when it is present in more than 10% of DNA-containing blood cells, the mutation was detected in about 17% of participants, and the frequency of its occurrence increased with age. At the same time, in patients with diagnosed Alzheimer's disease, the frequency of detection of this mutation was higher than the average. In addition, the presence of LOY was a marker of an increased likelihood of developing the disease during the subsequent follow-up period.

Given that women do not have a Y chromosome, and men on average live less than women, it can be assumed that LOY may be the cause of earlier mortality of men. However, the researchers note that the mechanisms and causes of the revealed pattern are currently unclear. Currently, they are studying the functional effects of LOY and finding out its effect on various groups of men, as well as its role in the development of other diseases, including different types of cancer. In addition, they are going to find out whether there is a relationship between this mutation and early manifestations of dementia, such as moderate cognitive impairment.

Another task is to elucidate the mechanisms linking LOY in leukocytes with diseases of other organs. According to Professor Forsberg, these cells are an essential component of the immune system, which suggests that the presence of LOY is associated with a partial loss of immune function.

The results of earlier work by the authors showed that smoking increases the risk of LOY by 400%, but this effect is transient and dose-dependent, so quitting smoking often eliminates its manifestations. The authors note that this fact can be used as part of anti-smoking campaigns.

Also, the LOY detection test in leukocytes can be used to identify men at risk for subsequent examination in order to detect early neurological and oncological symptoms. And in combination with other biomarkers, it can become an important diagnostic tool for predicting the risk of developing various diseases.

The results of the work were presented at the conference of the European Society of Human Genetics, held on May 21-24 in Barcelona, Spain.

Article by Lars Forsberg et al. Mosaic loss of chromosome Y in blood is associated with Alzheimer's disease published in the American Journal of Human Genetics.

Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru according to The European Society of Human Genetics: Loss of Y chromosome in blood cells is associated with developing Alzheimer's disease: new research could lead to a simple test to identify those at risk.


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