October 13, 2008
Baldness Genes Discovered
International researchers have uncovered genes that may increase by seven-fold the risk of early baldness amongst men.
Two stretches of the genome linked with the condition were found during an analysis of DNA from 5,000 volunteers with and without male-pattern baldness.
Nature Genetics reported that one in seven men have both genetic variants.
The researchers said being able to predict hair loss early could boost development of preventive treatments.
An initial study in more than 500 men with early onset hair loss and 500 men without the condition highlighted the two genetic regions, which substantially increased the risk of baldness.
The androgen receptor gene has already been linked to male-pattern baldness. But the other region is on chromosome 20 and is nowhere near any known gene.
Androgenic alopecia, or male pattern baldness, was already known to be hereditary and partly caused by male sex hormones.
The researchers said more work is needed to work out how this influences risk of baldness.
Researchers in other groups of people with androgenic alopecia confirmed the findings - including women in which they found a weaker association - in the UK, Iceland and the Netherlands.
Nature Genetics also published a second study that found a similar link between hair loss and chromosome 20.
The androgen gene which until now had been the only gene identified with baldness was on the X chromosome which is inherited from the mother, the German researchers said.
But they said chromosome 20 is inherited from both mother and father and may provide an explanation for similarities in hair loss between father and sons.
Around 14% of men carry both genetic variants, said Dr. Tim Spector, from Kings College London.
"At the moment we have a fairly good diagnostic tool for people who might want to know whether they will lose their hair before they are 50.
"There probably won't be many people who want to use that at the moment because there aren't any preventive treatments."
He hoped it would stimulate pharmaceutical companies to develop creams, gels or pills to prevent hair loss before it starts.
"The other thing is understanding how these genes actually work - it's likely to provide use with new targets for gene therapy which is actually quite easy to deliver to the hair follicle."
The work is very exciting, although it is debatable whether men would benefit from finding out about their hair loss risk, said Professor Val Randall, from the Centre for Skin Sciences at the University of Bradford.
"It is always easier to prevent than replace hair growth," she said.
"Male pattern baldness has a strong inherited aspect and understanding that may well lead to better treatments and novel approaches."
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