Men who have an extra sex chromosome, which is rare, have a higher risk of suffering from certain diseases.
- 90% of diabetics have type 2 diabetes.
- A ruptured atherosclerotic plaque is the cause of 80% of sudden deaths.
One in 500 men carry an extra sex chromosome. This means that instead of just having the usual two sex chromosomes, X and Y, they have one more. Thus, they therefore have two possible combinations: either XXY or XYY. According to English researchers from the universities of Cambridge and Exeter, this characteristic is rather negative because this additional chromosome exposes you to a higher risk of developing certain diseases with serious consequences such as type 2 diabetes, atherosclerosis and thrombosis. Their work has been published in the journal Genetics in Medicine.
356 men with an extra sex chromosome out of 200,000
In their study, the researchers analyzed the genetic and health data of more than 200,000 British men between the ages of 40 and 70. Thus, they found 356 men carrying either an extra X or Y chromosome. Generally, men with this chromosomal abnormality do not have any particular characteristics or symptoms. Genetic testing is required to make the diagnosis. In detail, scientists have identified 213 men with an extra X chromosome and 143 men with an extra Y chromosome. Prior to this study, only a small minority of them had been diagnosed with their chromosomal abnormality.
Fertility problems
The scientists then analyzed the health data of the 356 men who had an extra sex chromosome. Thus, they discovered that those with an extra X chromosome had fertility problems, lower testosterone and a three times higher risk of delayed puberty. On the other hand, those who had an extra Y chromosome did not have a fertility problem.
But all men with sex chromosome abnormalities had higher risks of developing certain diseases: three times higher for type 2 diabetes and pulmonary embolism and six times higher for venous thrombosis. For now, researchers do not know how to explain this link between extra chromosomes and increased risk.
Towards a screening of sex chromosomes?
“Even though a significant number of men carry an extra sex chromosome, very few of them are likely to know about it. This extra chromosome means they are at much higher risk of developing a number of metabolic, vascular and and respiratory diseases, pathologies that could be avoided”, concludes Yajie Zhao, one of the authors. In the future, the scientists intend to continue research in order to evaluate the interest of a systematic screening of the sex chromosomes in the population.