One in 500 men carries an extra sex chromosome, putting them at risk of many common diseases

One in 500 men carries an extra sex chromosome, putting them at risk of many common diseases

About one in 500 men can carry an extra X or Y chromosome - most of them unaware - putting them at increased risk for diseases such as type 2 diabetes, atherosclerosis, and thrombosis, researchers at the Universities of Cambridge and Exeter said.

In a study published in Genetics in Medicine, researchers analyzed genetic data collected on more than 200,000 British men aged 40-70 from the UK Biobank, a biomedical database, and research resource containing genetic, lifestyle and health information. Anonymous from half a million British participants. They discovered 356 men who had either an extra X or an extra Y chromosome.

Sex chromosomes determine our biological sex. Men typically have one X and one Y chromosome, whereas women typically have two Xs. Some men, however, have an extra X or Y chromosome - XXY or XYY.

Without genetic testing, it may not be immediately apparent. Men with extra X chromosomes are sometimes identified during investigations into delayed puberty and infertility; However, most are not aware that they have the condition. Men with an extra Y chromosome tend to be taller than boys and adults, but other than that, they don't have distinct physical features.

Researchers identified 213 men with an extra X chromosome and 143 men with an extra Y chromosome in today's study. As UK Biobank participants tend to be 'healthier' than the general population, this suggests that as many as 1 in 500 men may carry an extra X or Y chromosome.

Only a small minority of these men had a diagnosis of a sex chromosomal abnormality in their medical records or by self-report: less than one in four (23%) men with XXY and only one in 143 XYY men (0.7%) had the known diagnosis.

By correlating genetic data with routine health records, the team found that men with XXY had a significantly greater chance of reproductive problems, including a threefold risk of delayed puberty, and a fourfold risk of childlessness. These men also had very low blood concentrations of testosterone, the natural male hormone. XYY men appear to have a normal reproductive function.

Men with XXY or XYY have a higher risk of many other health conditions. They were three times more likely to develop type 2 diabetes, six times more likely to suffer from venous thrombosis, three times more likely to suffer from a pulmonary embolism., and four times more likely to have chronic obstructive pulmonary disease (COPD).

The researchers say it's not clear why the extra chromosome should increase the risk or why the risks are similar regardless of which sex chromosome was transcribed.

Yaji Chao, Ph.D. A student in the Medical Research Council (MRC) Epidemiology Unit at the University of Cambridge, the first author of the study, said: 'Although a large number of men carry an extra sex chromosome, it is very likely that few are aware of it. The additional thing is that they have a much higher risk of a number of common metabolic, vascular and respiratory diseases — diseases that are preventable.”

Professor Ken Ong, also from the Epidemiology Unit at Cambridge Medical Research Center and senior author of the study, added: "Genetic testing can detect chromosomal abnormalities fairly easily, so it may be useful if XXY and XYY are tested more extensively in men who attend To the doctor. With related health concerns.

"More research is needed to assess whether there is additional value in the broader screening of abnormal chromosomes in the general population, but that this may lead to early interventions to help them avoid related diseases."

"Our study is important because it starts with genetics and tells us about the potential health effects of having an extra chromosome," said Professor Anna Murray of the University of Exeter. sex chromosome in older populations, without prejudice by testing only men with some features as has often happened in the past."

Previous studies have found that one in 1,000 females has an extra X chromosome, which can lead to delayed language development and faster growth into adulthood, as well as lower levels of intelligence compared to their peers.


The Medical Research Council-funded the study.


Materials provided by the University of Cambridge. 


Yajie Zhao, Eugene J. Gardner, Marcus A. Tuke, Huairen Zhang, Maik Pietzner, Mine Koprulu, Raina Y. Jia, Katherine S. Ruth, Andrew R. Wood, Robin N. Beaumont, Jessica Tyrrell, Samuel E. Jones, Hana Lango Allen, Felix R. Day, Claudia Langenberg, Timothy M. Frayling, Michael N. Weedon, John R.B. Perry, Ken K. Ong, Anna Murray. Detection and characterization of male sex chromosome abnormalities in the UK Biobank study. Genetics in Medicine, 2022; DOI: 10.1016/j.gim.2022.05.011


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