Alopecia Genes
Alopecia Areata
Hair normally grows at a rate of about one centimeter a month (roughly one-third of an inch). At the end of the hair growth cycle, the hair falls out and a new hair starts to grow. Normally, people lose about 100 hairs a day.
Alopecia areata is a disease caused by an autoimmune attack on the hair follicles, causing the hairs in the affected follicles to fall out. The hair loss occurs in smooth, round or oval patches about the size of a quarter. A variant of the condition is alopecia areata totalis, or total loss of all hair on the scalp. A third variant is alopecia areata universalis, which causes a loss of hair over the whole body. Of the three types, alopecia areata is the most common and alopecia areata universalis is the rarest.
According to the National Alopecia Areata Foundation, more than 4.7 million Americans have some degree of alopecia areata. It most commonly first appears in childhood or young adulthood. At least 20 percent of patients have a family history of the disease.
Hair loss from alopecia areata can be emotionally upsetting. There are some treatments available, but no cure. So if the treatment is halted while the disease is active, hair loss recurs. One important factor in alopecia areata is that the hair follicle itself is not destroyed and maintains the potential to re-grow a new hair. In fact, scientists estimate up to 50 percent of patients recover within one year. However, the more severe the disease, the less likely there will be a recovery.
Genetic Clues
Researchers at Columbia University in New York City theorized that since alopecia areata is an autoimmune disease, it may share some of the same genes as other autoimmune diseases. The investigators studied the DNA from blood samples taken from alopecia areata patients who were registered with the National Institute of Arthritis and Musculoskeletal and Skin Diseases (a division of the National Institutes of Health, or NIH). The genes from those samples were compared to those without the disease. The goal was to find genes which were commonly expressed in the alopecia group, but not in the normal controls.
When the scientists looked at their results, they found several common genes associated with alopecia areata. More importantly, these are the same genes associated with three other autoimmune conditions: type 1 diabetes, celiac disease and rheumatoid arthritis. Angela Christiano, Ph.D., Genetics/Dermatology Professor, says researchers may be able to find a way to manipulate these genes and tone down the immune system’s attack on the cells in the hair follicle.
The DNA findings provide some hope for alopecia areata patients. First, since the three other conditions already have proven treatments, researchers may be able to test some of these other treatments for alopecia. Second, scientists may eventually be able to develop a DNA test to help doctors determine the course of disease and best treatments for patients in the future.
AUDIENCE INQUIRYFor general information on alopecia:
American Academy of Dermatology, http://www.aad.org
National Alopecia Areata Foundation, http://www.naaf.org
National Institute of Arthritis and Musculoskeletal and Skin Diseases, http://www.niams.nih.gov
BIBLIOGRAPHY“Help with Hair Loss,” American Family Physician, August 15, 2009, Vol. 80, No. 4, pp. 373-374.
“Human Leukocyte Antigen Class II Alleles are Associated with Risk of Alopecia Areata,” Journal of Investigative Dermatology, January 2008, Vol. 128, No. 1, pp. 240-243.
Mounsey, Anne, M.D., and Sean Reed, “Diagnosing and Treating Hair Loss,” American Family Physician, August 15, 2009, Vol. 80, No. 4, pp. 356-362.
Mukherjee, Niyati, et al., “Attitudes of Dermatologists in the Southeastern United States Regarding Treatment of Alopecia Areata,” BMC Dermatology, November 12, 2009, Vol. 9, p. 11.
Strober, Bruce, M.D., Ph.D., et al., “Alefacept for Severe Alopecia Areata,” Archives of Dermatology, November 2009, Vol. 145, No. 11, pp. 1262-1266.
