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Contact: Tonya Ewers, 303.724.1524, pager 303.266.0941, Tonya.Ewers@uchsc.edu
Romanian Community Provides Insight into the Genetic Factors of Vitiligo
University of Colorado Denver researchers study community with a 19 percent higher occurrence of the skin and hair pigment disorder than its surrounding villages
AURORA, Colo. (March 17, 2008) - An isolated, inbred Romanian community has a higher than average frequency of the skin disease vitiligo and other autoimmune diseases, suggesting a genetic variation that may indicate susceptibility to the condition in a broader population, according to a report in the March issue of Archives of Dermatology, one of the JAMA/Archives journals.
Vitiligo is a disorder in which progressive patches of skin, hair and mucous membranes lose color due to a decrease in the number of pigment-producing cells known as melanocytes. It affects about 0.38 percent of whites and occurs with similar frequency in populations worldwide. Researchers are attempting to identify the genes responsible for susceptibility to vitiligo, in part to identify pathways through which effective treatments might be developed.
Richard Spritz, MD, Director of the Human Medical Genetics Program at the University of Colorado Denver, and colleagues Stanca A. Birlea, MD, PhD, and Pamela Fain, PhD, studied 1,673 residents of a geographically isolated community in the mountains of northern Romania between 2001 and 2006. The researchers identified patients with vitiligo and obtained information on demographic data, genealogies, occurrence of other diseases and family structure. The skin of patients with vitiligo and their relatives was examined. During the study, researchers identified and examined 51 patients with vitiligo.
"The 2.9 percent frequency of vitiligo in the study community is 19.3 times its 0.15 percent frequency in the five surrounding villages, 7.5 times that among whites on the island of Bornholm, 5.7 times that among individuals in Calcutta, India and 22.5 times that among Han Chinese in Shaanxi Province, China, the only other populations for which empirically determined prevalence estimates have been published," the authors write. Rates of other autoimmune diseases, including thyroid disease, adult-onset type 1 diabetes and rheumatoid arthritis, were also elevated in the community.
However, the average age at which symptoms of vitiligo first developed was 36.5 years, significantly older than the average age of onset among white individuals (24.2 years). Analyses indicated that this unusual factor most likely was not genetic. "Whereas disease susceptibility seems to involve a major genetic component, actual onset of vitiligo in genetically susceptible individuals seems to require exposure to environmental triggers," said the authors.
"This was really surprising to us," explains Dr. Spritz. "It appears that genes determine who is susceptible to getting vitiligo, but non-genetic factors, such as exposure to an environmental 'trigger', determine who actually gets it and when."
The community's isolation may make it easier for researchers to identify mutated genes that increase risk for vitiligo in this population. "While this gene variant is of particular importance in this isolated special population, it likely is also involved in disease susceptibility in the broader white population and, thus, is of broader importance," they write.
This study was supported by grants from the National Institutes of Health and a grant from the American Skin Association.
The School of Medicine faculty work to advance science and improve care as the physicians, educators and scientists at University of Colorado Hospital, The Children's Hospital, Denver Health, National Jewish Medical and Research Center, and the Denver Veterans Affairs Medical Center. Degrees offered by the UC Denver School of Medicine include doctor of medicine, doctor of physical therapy, and masters of physician assistant studies. The School is part of the University of Colorado Denver, one of three universities in the University of Colorado system. For additional news and information, please visit the UC Denver newsroom online.