One in 500 men carry an extra sex chromosome

The XX or XY chromosomes define the sex of an individual, but in a significant proportion of men, there may be one too many. People XXY or XYY would then be subject to different health problems as indicated by a recent study conducted at the University of Cambridge.

The genetic heritage of the human being is condensed into 23 pairs of chromosomes, one of which is responsible for sex: XX for women and XY for men. But, according to researchers at the University of Cambridgea non-negligible proportion of men have a chromosomal abnormality.

Indeed, after analyzing medical data from the BioBank UKthey showed that about one in 500 men has a chromosome sexual, X or Y and more! These men concerned therefore do not have 46 chromosomes but 47 with a sexual signature XXY or XYY. Without making a karyotype, this anomaly often goes unnoticed. Only 23% of 47XXY men participating in this study were aware of its existence, and 0.7% for 47XYY. However, Cambridge scientists have shown that this chromosome supernumerary could contribute to certain health problems.

An extra sex chromosome favors the appearance of certain diseases

47XXY men can sometimes be diagnosed during puberty. Indeed, this anomaly is known as syndrome of Klinefelter and tends to delay puberty in adolescents and cause problems withinfertility in adults. 47XYY males are often taller than average, but beyond that there is no evidence that the abnormality exists in them.

Although a significant number of men gate an extra sex chromosome, very few of them are likely to be aware of. This extra chromosome means they have significantly higher risks of a number of common metabolic, vascular and respiratory diseases — diseases that may be preventable », explains Yajie Zhaofirst author of the study.

By making the link between their chromosomal particularity and the health problems that the 356 men, aged 40 to 70, developed during the follow-up, the scientists were able to light that phenotypes XXY and XYY increase the risk of type 2 diabetes,pulmonary embolismand of chronic obstructive pulmonary disease also called COPD. A genetic test can make it possible to identify the anomaly “quite easily” observes Ken Ong, scientist in the same research team. It could become a risk factor to be taken into account in the medical follow-up of the patients concerned.

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