Male baldness genes found

Good news for any of our listeners who are thinning on top - two papers in Nature Genetics this week reveal genetic variations that contribute to male pattern baldness, which affects around a third if men by the time they're 45. It's the classic pattern of baldness where hair starts thinning at the temples. It's thought to be hereditary in around eight out of ten cases.

Researchers have known for some time that there must be a gene linked to hair loss on the X chromosome - the female sex chromosome. This is the basis of the idea that baldness is inherited from the mother's side of the family. But the evidence has pointed to the role of other genes, which have been unknown until now.

The first paper, from scientists at McGill University, King's College London and GlaxoSmithKline Inc. describes two genetic variants in Caucasian men that, if found together, increase a man's risk of baldness by seven times. To find them, the researchers scanned through the genomes of 1,125 men who had been assessed for male pattern baldness.

The team found two previously unknown gene variations on chromosome 20 that substantially increased the risk of male pattern baldness. They then confirmed these findings in an additional 1,650 men. And rather surprisingly, the scientists showed that one in seven men carry both of the baldness variations.

Another team of scientists at Bonn and Dusseldorf Universities carried out similar studies on 300 men with hair loss, and pinned down an area of the genome on the X chromosome containing the androgen receptor, which binds male sex hormones. Previous research had already shown a role for this gene in baldness.  But the study also revealed the same region on chromosome 20 that was also found by the team mentioned earlier.

The discovery of a gene linked to baldness that isn't on the X chromosome, which can only be inherited from the mother, may explain the similarity between hair loss patterns in fathers and sons.

Sadly, although the researchers say their discovery is a scientific breakthrough, they caution that it does not mean a treatment or cure for male pattern baldness is around the corner. But they suggest that being able to predict if someone might lose their hair could lead to effective preventive strategies.