A Romanian population isolate with high frequency of vitiligo and associated autoimmune diseases.

OBJECTIVE To characterize the epidemiology and genetics of vitiligo and associated autoimmune diseases in a population isolate in Romania in which there is a high frequency of these diseases. DESIGN Prospective and retrospective ascertainment of all patients and extended families with these disorders in the study community. SETTING A geographically isolated community in the mountains of northern Romania. Patients Fifty-one affected individuals and their close relatives from 35 nuclear families in an extended kindred that effectively constitutes the entire community population. MAIN OUTCOME MEASURES Demographic, phenotypic, and genetic aspects of vitiligo and other autoimmune diseases in the extended kindred. RESULTS The frequencies of vitiligo and several other autoimmune diseases, including autoimmune thyroid disease, adult-onset autoimmune diabetes mellitus, and rheumatoid arthritis, are greatly elevated. The age of vitiligo onset in this village is relatively delayed, suggesting that the causes of vitiligo in this community may be somewhat atypical. Genetic segregation analysis is most consistent with a single major locus recessive model, although incomplete penetrance and heritability suggest that other genes and nongenetic factors likely influence occurrence of disease in homozygotes. CONCLUSIONS The high frequency of vitiligo and other autoimmune diseases in this isolated inbred community and an unusual aspect of the vitiligo phenotype suggest that susceptibility to these disorders in this "special population" may be unusual, likely involving a major recessive gene. 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.