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Scientists at McGill, King's College and GSK solve mystery of male pattern baldness.
Researchers at McGill University, King's College London and GlaxoSmithKline Inc. have identified two genetic variants in caucasians that together produce an astounding sevenfold increase the risk of male pattern baldness. Their results will be published Oct. 12 in the journal Nature Genetics.
About a third of all men are affected by male pattern baldness by age 45. The condition's social and economic impact is considerable: expenditures for hair transplantation in the United States alone exceeded $115 million (U.S.) in 2007, while global revenues for medical therapy for male-pattern baldness recently surpassed $405 million. Male pattern baldness is the most common form of baldness, where hair is lost in a well-defined pattern beginning above both temples, and results in a distinctive M-shaped hairline. Estimates suggest more than 80 per cent of cases are hereditary.
This study was conducted by Dr. Vincent Mooser of GlaxoSmithKline, Dr. Brent Richards of McGill University's Faculty of Medicine and the affiliated Jewish General Hospital (and formerly of King's College), and Dr. Tim Spector of King's College. Along with colleagues in Iceland, Switzerland and the Netherlands, the researchers conducted a genome-wide association study of 1,125 caucasian men who had been assessed for male pattern baldness. They found two previously unknown genetic variants on chromosome 20 that substantially increased the risk of male pattern baldness. They then confirmed these findings in an additional 1,650 caucasian men.
"I would presume male pattern baldness is caused by the same genetic variation in non-caucasians," said Richards, an assistant professor in genetic epidemiology, "but we haven't studied those populations, so we can't say for certain."
Though the researchers consider their discovery to be a scientific breakthrough, they caution that it does not mean a treatment or cure for male pattern baldness is imminent.
"We've only identified a cause," Richards said. "Treating male pattern baldness will require more research. But, of course, the first step in finding a way to treat most conditions it is to first identify the cause."
"Early prediction before hair loss starts may lead to some interesting therapies that are more effective than treating late stage hair loss," added Spector, of King's College and director of the TwinsUK cohort study.
Researchers have long been aware of a genetic variant on the X chromosome that was linked to male pattern baldness, Richards said.
"That's where the idea that baldness is inherited from the mother's side of the family comes from," he explained. "However it's been long recognized that that there must be several genes causing male pattern baldness. Until now, no one could identify those other genes. If you have both the risk variants we discovered on chromosome 20 and the unrelated known variant on the X chromosome, your risk of becoming bald increases sevenfold."
"What's startling is that one in seven men have both of those risk variants. That's 14 per cent of the total population!"
3 days in the Sydney clinic by David Salinger.
The following is a summary of patients seen over three days (or spoken to on the phone) in my Sydney clinic. I normally spend about 30 minutes with each patient and always give the scalp and hair a good examination, at least once. I can also observe the scalp through the dermascope (at 50X), which allows me to see if there is any erythema of the scalp or follicles and any swelling around the hair follicles.
A 53 year-old patient, Margaret, phoned to say she is feeling a lot better. She was referred to me last November by another patient. She had had excessive hair loss for 4 years and also suffered from tiredness, polyuria, excessive thirst, dizziness and bloating. She brought along some blood tests, which showed ferritin to be 80, a good level, but other iron tests were not run. Other tests, including B12, Vitamin D and TSH, were all normal.
She was taking the diuretic ‘lasix’, which could have accounted for some of her symptoms. When I saw her last November, she looked unwell and, because the cause of her hair loss was not obvious, I wrote a letter to her doctor asking for some further blood tests, including serum iron and tests for gluten intolerance. It turned out that her serum iron was almost zero and she is now taking some iron. The test for gluten intolerance was positive so she is now off all gluten foods and her bloating has ceased.
(If one takes an iron supplement but serum iron does not increase, then malabsorption is indicated and it is likely other minerals are also low. In such cases, it is always worth checking for gluten intolerance. She has now been on iron for 2 months and I am hoping her hair loss will slow within another 4 months. Her doctor has also prescribed an antidepressant. This case also emphasises that blood tests for iron should include both serum iron and ferritin.)
A 52 year-old female, Joan, came in with her daughter. I had first seen Joan in October, 2005 when she advised me that the patch of baldness at the back of her scalp had been diagnosed as lichen simplex (neurodermatitis) based on a biopsy. It had started as a pimple, two years’ previous. She had rubbed at it over time and a hard crust had developed. She had cut the hard skin away herself six months before, but the area in question was still enraged and there was a hard lump there. The alopecia looked to me like a severe autoimmune reaction, similar to alopecia areata, and did not look like lichen simplex at all. I advised Joan to obtain a second opinion from a dermatologist on the problem.