Major Histocompatibility Complex Class I Chain-Related Gene A Polymorphisms and Extended Haplotypes Are Associated with Familial Alopecia Areata

The study explored the genetic associations between alopecia areata (AA) and markers in the major histocompatibility complex (MHC) region, particularly the MICA gene, involving 176 affected and 231 unaffected individuals from 84 families. It found that the MICA*6 allele was linked to all AA phenotypes, while MICA*5.1 was associated with patchy AA. Extended haplotypes like HLA-DQ1-DR6-MICA*5.1 were significantly associated with AA, suggesting MICA as a candidate gene for AA susceptibility and severity. These genetic markers could potentially differentiate between mild and severe AA, though further research was needed to clarify the functional role of MICA alleles in AA.