One in 500 men carry extra sex chromosome, research suggests

[cbabe]

One in 500 men carry extra sex chromosome, research suggests

https://www.theguardian.com/society/2022/jun/10/men-extra-sex-chromosome-research-uk-health-issues

Ian Sample Science editor
@iansample
Fri 10 Jun 2022 09.25 EDT

Twice as many men carry an extra sex chromosome as previously thought, according to researchers who called for more genetic testing to identify people at greater risk of related medical problems.

Research on more than 200,000 men enrolled with the UK Biobank suggests that about one in 500 in the general population has an extra X or Y chromosome, double the number found in earlier work, though only a fraction are likely to be aware of it.

While most men have one X and one Y chromosome, some are born XXY or XYY, putting them at increased risk of health issues ranging from type 2 diabetes, blocked blood vessels and chronic obstructive pulmonary disease (COPD), a lung condition, the study found.

“We were surprised at how common this is,” said Prof Ken Ong, a paediatric endocrinologist at the MRC epidemiology unit at Cambridge and a senior author on the study. “It had been thought to be pretty rare.”

Working with colleagues at the University of Exeter, the Cambridge team examined DNA from 207,067 men of European ancestry aged from 40 to 70 years old. They identified 231 men with an extra X chromosome and 143 men with an extra Y chromosome. Those enrolled with the UK Biobank tend to be healthier than average, but from the data, the scientists estimate that 1 in 500 men in the general population carry an extra X or Y chromosome.

Among the men flagged up in the study, published in Genetics in Medicine, only 23% of those XXY and 0.7% of those XYY had a known diagnosis of an extra chromosome, suggesting there was little awareness of the condition.

Men with an additional X chromosome are often diagnosed when it has an impact on puberty and fertility, though it is also linked to higher body fat, cognitive problems and personality disorders. In the study, XXY men had substantially lower testosterone than XY men, a threefold greater risk of delayed puberty, and a fourfold higher risk of being childless. The effects of an extra Y chromosome are less well understood. XYY men tend to be taller as boys and adults, but appear to have normal reproductive function.

Previous research suggests that about 1 in 1,000 women carry an additional X chromosome, which can lead to similar effects, ranging from faster growth until puberty, delayed language development and reduced IQ compared with their XX peers.

Analysis of the men’s health records found that carrying either extra sex chromosome raised the risks of several medical conditions. Compared with XY men, carrying an extra sex chromosome tripled the risk of type 2 diabetes and blocked blood vessels in the lungs, quadrupled the risk of COPD, and raised the risk of blocked veins sixfold, the researchers found. It is unclear why the extra chromosomes have such an impact, and why it is similar regardless of the chromosome that is duplicated.

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[Bongo Prophet]

1. That doesn't sound nearly as much fun as it initially seemed from the headline

[Kali]

2. interesting

thanks for posting

[cbabe]

3. Wondering how this will change the 'let's make trans kids illegal' laws.

[Act_of_Reparation]

4. It won't.

The "let's make trans kids illegal" crowd don't care what science says.

[cbabe]

5. Doctors doing the testing would have to follow the science. Or jeopardize their license?

[Act_of_Reparation]

6. They would have to follow the law.

It all depends on how the law defines gender.

[cbabe]

8. Challenge the law with new science. For example, racist laws.

[keithbvadu2]

7. Eve was the first transgender. Originally 100% male.

God thought that was OK.

[Ms. Toad]

9. Variations in sex are nothing new.

https://www.scientificamerican.com/article/sex-redefined-the-idea-of-2-sexes-is-overly-simplistic1/

All this new study does is suggest that if we tested we would identify more people than expected who aren't the standard XY = secondary sex characteristics historically identified as male; XX = secondary sex characteristics historically identified as female but aren't aware of the discrepancy.

The fact that it is slightly more common than previously estimated won't make a dent on the people who are fixated on the concept that gender is binary.

[cbabe]

10. Challenge bigots to get tested. Same as challenging kids on the little league team.

[AntiFascist]

13. I doubt if many trans people have this condition...

just as there is no simple genetic explanation for homosexuality.
It may relate more to intersex people, but not necessarily a complete explanation.

[Higherarky]

11. XY v. XX

Is it possible the standard XY v XX configuration suggests the standard male lacks a "leg" in his Y chromosome which is present in the standard female, which therefore renders him incapable of certain functions of which a female is capable?

[Wounded Bear]

12. So, is this test more or less intrusive than "Everybody drop your drawers!"

Asking for a friend.