Scientists have identified a genetic mutation that causes a rare form of baldness. The finding, reported in tomorrow's issue of Science, indicates that the affected gene regulates hair growth, and it is the first such gene to be identified in humans. Ultimately, a better understanding of what controls hair growth could lead to improved treatments for more common forms of baldness, as well as for people with unwanted hair growth and burn victims.
The research began in Pakistan, where several cases of a rare form of inherited baldness had been reported within the same family. Although born with hair, the affected people lost it in early infancy, and from then on had no hair at all on their body. Using a technique called radiation hybrid mapping to analyze the family's DNA, geneticist Angela Christiano of Columbia University in New York City was able to pin the gene down to a location on the eighth chromosome. But no genes had been mapped in that particular stretch, and, Christiano says, sequencing "would have taken years."
Luckily, Christiano learned at a conference about a breed of mice with similar symptoms that had a mutation in a gene called hairless, which had already been sequenced. Christiano went hunting on the human eighth chromosome and found a match: a stretch of 1189 amino acids that were 80% identical to the mouse sequence. To top it off, she compared that stretch of the bald people's DNA with the same stretch of DNA from normal Pakistanis. Every one of the seven bald family members had an identical mutation at the 1022nd position, and none of the unaffected people did.
The finding is a "great breakthrough," says John Sundberg of the Jackson Laboratories in Bar Harbor, Maine, but he notes that the gene is linked to a specific type of inherited baldness, not a more common autoimmune disease that is also called alopecia universalis. Still, given that research into hair diseases is not heavily funded, "this is a crack in the door," says Lowell Goldsmith, a dermatologist at the University of Rochester School of Medicine and Dentistry in New York.