Major locus on mouse chromosome 17 and minor locus on chromosome 9 are linked with alopecia areata in C3H/HeJ mice.

Alopecia areata is an autoimmune disease that targets actively growing (anagen) hair follicles in humans, mice, rats, dogs, horses, and cattle. C3H/HeJ mice spontaneously develop alopecia areata from 5 mo of age and older in females and later in males. Frequency of disease approached 20% in a colony by 18 mo of age. C57BL/6J mice do not develop alopecia areata. A segregating F2 population of female mice (n=1096) was generated from crossing these two strains. Alopecia areata (n=138) and clinically normal (n=214) mice were genotyped at 12 mo of age using 211 microsatellite probes. The peak logarithm of odds ratio score on mouse chromosome 17 (10.9) was around marker D17Mit134 at 16.9 cM from the centromere. The mouse histocompatibility locus, H2, the mouse equivalent of human leukocyte antigen in humans, was a likely candidate. Twelve-month-old C3H.SW-H2b/SnJ mice (C3H/HeJ congenic mice in which the H2k purported susceptibility locus was replaced with the H2b purported resistance locus) did not develop alopecia areata, supporting this locus as being important in alopecia areata. A suggestive linkage was also found on mouse Chromosome 9 (logarithm of odds ratio score 2.0) around D9Mit206, 20 cM from the centromere. The interval on mouse Chromosome 17 contains several orthologous genes potentially associated with human alopecia areata.