(IL2RA molecule OR IL2RA) AND (polymorphism OR mutation OR variant) AND “Alopecia Areata’’(IL17A molecule OR IL17A) AND (polymorphism OR mutation OR variant) AND “Alopecia Areata’’(IL12B molecule OR IL12B) AND (polymorphism OR mutation OR variant) AND “Alopecia Areata’’(IL23R molecule OR IL23R) AND (polymorphism OR mutation OR variant) AND “Alopecia Areata’’. This evidence concerns the gene IL12B and alopecia areata.