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April 14, 2010

Hair Loss Gene Discovered

Researchers have discovered a gene that is involved in human hair growth, a development that might one day lead to safe treatments for common forms of baldness.

Scientists discovered the gene, called APCDD1, while studying a rare condition among several families in Pakistan and Italy that causes progressive baldness.  

Angela Christiano is professor of molecular dermatology at Columbia University.  She led the team of investigators from Columbia and Rockefeller Universities in New York, Stanford University in California, as well as scientists from Pakistan and Italy.

Christiano says the disease, hereditary hypotrichosis simplex, causes a shrinkage of the hair follicle on the scalp. "Imagine putting a picture of a hair follicle on a photocopier and hitting reduce.  It's a proportional reduction in the size of the hair follicle, so that instead of making a nice long, thick head hair like what grows on your scalp, you make a peach fuzz hair that is smaller and less pigmented," she said.

Christiano and her colleagues studying two families in Pakistan and a third in Italy with hereditary hypotrichosis, found a common mutation in the APCCD1 gene. "The gene is involved in Wnt [WINT] signaling, which is basically an accelerator - like an accelerator pedal in a car for hair growth.  And we found this inhibitor of Wnt signaling, when it's interrupted, leads to hair falling out or loss of hair," she said.

Wnt signaling has been shown to control hair growth in mice.  This is the first time it's been seen in humans.

In the case of the Pakistani and Italian families, hair loss begins at an early age and individuals are not able to grow their hair very long.  The disease is passed from one generation to the next.

The most common form of baldness in men, called male pattern baldness, has been linked to a gene that regulates the male hormone testosterone.  That's why many of the treatments for baldness contain hormones, which researchers say, might not be completely safe or effective.

Columbia University's Angela Christiano says the follicle miniaturization seen in hypotrichosis is also seen in male pattern baldness.  But the gradual hair loss seen in most men as they age is different than that of the Pakistani and Italian families. "While this gene gives us a handle on the biology of miniaturization, it wouldn't be yet called a target for a drug for hair growth," she said.

But researchers say the discovery could one day lead to safe and effective treatments for hair loss that do not involve the use of hormones.  Discovery of the hair growth gene is reported in this week's issue of the journal Nature.