Bald men can blame mum!

May 22 2005

Despite an enormous range of treatments, obscure lotions and tinctures there appears to be very few successful counter-measures for hair loss in men. Beginning with receding hairlines, every second man suffers from hair loss to some degree, and it has always been suspected that hereditary factors are important in causing hair loss.

Until recently however scientists were unclear which genes were involved. Now for the first time researchers in Germany appear to have discovered one of the factors responsible.

The research team headed by Professor Markus Nothen of the Life & Brain Centre of Bonn University and Dr. Roland Kruse of the Skin Clinic of Dusseldorf University, searched nationwide for families in which several men were affected by hair loss. Blood samples were taken from the volunteers and scrutinised for candidate genes, which were ultimately discovered.

The team initially succeeded in narrowing down the search to a series of areas on various chromosomes, and in an area where the largest contribution was suspected lay the gene for the androgen receptor.

Professor Nothen says they found one variant of a particular gene was evident much more often among men who suffered from premature balding at a very early stage than among men who still had a full head of hair when over 60.

Axel Hillmer, a member of the team, says it is probable that the genetic variant results in more androgen receptors in the scalp. He says either more androgen receptors are formed among the men affected, or the variant of the receptor which develops as a result of the genetic change is more stable and is not broken down so quickly. Both mechanisms can lead to the effect of the androgens becoming greater, which in turn brings about hair loss.

The findings are interesting in explaining how hair loss is inherited. The gene for the androgen receptor lies on the x chromosome. Men always inherit the x chromosome from their mother. In many cases men therefore take after their grandfather on their mother's side rather than their father.

However, Prof. Nothen does stress that this defect is not simply caused by one gene, as they have seen indications that other genes are involved which are independent of the parents' sex. He says the hereditary defect can therefore sometimes also be passed on directly from father to son.

The research team is looking for more volunteers in order to identify more genes involved Dr. Kruse says men under 40 with severe hair loss can take part, and if they have a brother who is affected and the parents are also prepared to give blood samples, so much the better. Volunteers taking part in the study will be paid for their assistance.