D6

By Sheryl Ubelacker
The Canadian Press

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TORONTO - A new genetic discovery suggests that some men's hair loss may not be all mom's fault after all.

Two groups of international researchers, including one team with members from Canada, have independently found a region of DNA that appears to increase some men's susceptibility to male pattern baldness.

Scientists have long known there is a genetic variant passed from mothers to sons via the X chromosome that causes men to start losing their hair by the time they reach middle-age.

"That's where the idea that baldness is inherited from the mother's side of the family comes from," said Dr. Brent Richards, an endocrinologist at McGill University and lead author of one of the studies. "However, it's been long recognized that there must be several genes causing male pattern baldness."

The newly identified genetic region "is in an entirely novel area on chromosome 20," Richards said from Montreal, noting that men who have both genetic variations on the two chromosomes have a sevenfold higher risk of seeing their hairline recede over time.

He said one in seven men - or 14 per cent of the population - have both genetic anomalies.

"How this novel gene or area of the genome influences male pattern baldness will require a lot more research."

About one-third of men are affected by male pattern baldness - the most common type of hair loss - by age 45. The loss begins above both temples and results in a distinctive M-shaped hairline. More than 80 per cent of cases are believed to be hereditary.

Hair loss affects about 40 per cent of women, mostly after menopause, but Richards said more research is needed to determine what role - if any - the area on chromosome 20 plays in females.