Researchers from the universities of Cambridge and Exeter suggest that one in 500 men may be carrying an additional X or Y chromosome, putting them at an elevated risk of diseases such as type 2 diabetes, atherosclerosis, and thrombosis.
Over half a million UK men aged 40 to 70 were studied for their genetic information, which was collected anonymously from UK Biobank, a biomedical directory and data analysis resource that contains genetic, lifestyle, and medical data on over 200,000 individuals. The findings were published in the journal Genetics in Medicine. They discovered 356 guys who had an additional X or Y chromosome in their DNA.
Our biological sex is determined by our sex chromosomes. When it comes to gender, men and women are separated by one or two sets of Xs and Ys, respectively. However, an additional X or Y chromosome – XXY or XYY – can be found in some men.
Genetic testing may not reveal it right away. However, most men with an additional X chromosome are unaware that they have this issue, which is often found during studies of delayed puberty and infertility. As boys and adults, men with an additional Y chromosome tend to be taller, but this is about it in terms of their physical characteristics.
There were 213 men with an additional X and 143 with an additional Y chromosome discovered in today’s study. One in every 500 men in the UK Biobank may have an extra X or Y chromosome, based on the fact that participants are generally healthier than the overall population.
Fewer than one in four (23 percent) men with XXY and only one in 143 (0.7 percent) men with XYY had a confirmed diagnosis of sex chromosomal abnormalities in their health records or by self-report.
The researchers showed that males with XXY have a three-fold greater risk of delayed puberty and a four-fold greater risk of being childless when genetic data was linked to routine health information. The natural male hormone testosterone was also much lower in the blood of these men. The reproductive function of men with XYY was found to be normal.
Health disorders such as cancer, heart disease, and diabetes are more common in men with one or both of these genetic markers. Having type 2 diabetes, venous thrombosis, pulmonary embolism, and COPD were three times, six times, and four times more common for them than those without these conditions (COPD). Adding an extra chromosome doesn’t explain why the risk is so similar regardless of which sex chromosome is duplicated, according to the researchers.