Alopecia Areata 2

For a phenotypic description and a discussion of genetic heterogeneity of alopecia areata, see 104000.

Mapping

In an effort to define a genetic basis of alopecia areata, Martinez-Mir et al. (2007) performed a genomewide search for linkage to 20 families with 102 affected and 118 unaffected individuals from the United States and Israel. The analysis revealed evidence of at least 4 susceptibility loci on chromosome 6, 10, 16, and 18 using several different statistical approaches. Fine-mapping analysis with additional families yielded a maximum multipoint lod score of 3.93 on chromosome 18 (AA1; 104000), a 2-point affected sib pair (ASP) lod score of 3.11 on chromosome 16 at marker D16S415 (AA2), several ASP lod scores greater than 2.00 on chromosome 6q, and a haplotype-based relative risk lod of 2.00 on chromosome 6p, in the major histocompatibility complex locus.