title: Major histocompatibility complex class I chain-related gene A polymorphisms and extended haplotypes are associated with familial alopecia areata.
abstract: Alopecia areata (AA) is characterized by hair loss in patches and may progress to total loss of scalp hair, or total loss of scalp and body hair. The major histocompatibility complex (HLA) is associated with susceptibility to AA, as well as other autoimmune diseases. In addition to HLA molecules, non-HLA molecules including the major histocompatibility complex class I chain-related gene A (MICA), a stress-inducible antigen, are also associated with several autoimmune diseases. To investigate associations between AA and the HLA loci, two genes and eight microsatellite markers spanning the HLA region were genotyped. MICA(*)6 was significantly associated with all phenotypes of AA (P=0.0083), whereas MICA(*)5.1 was significantly associated with patchy AA (P=0.029). Extended haplotype analysis shows the significant associations of haplotypes HLA-DQ1-DR6-MICA(*)5.1 (P=0.004) and HLA-DQB1*0201-DR3-MICA(*)5.1 (P=0.009) with AA. These results suggest that MICA is both a potential candidate gene and part of an extended HLA haplotype that may contribute to susceptibility to and severity of AA.
authors.affiliation: Department of Dermatology, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA. nbarahma@mail.mdanderson.org
authors.forename: Nazila
authors.initials: N
authors.lastname: Barahmani
authors.forename: Mariza
authors.initials: M
authors.lastname: de Andrade
authors.forename: Joshua P
authors.initials: JP
authors.lastname: Slusser
authors.forename: Qing
authors.initials: Q
authors.lastname: Zhang
authors.forename: Madeleine
authors.initials: M
authors.lastname: Duvic
mesh_terms: D000483:Alleles; D000506:Alopecia Areata / Q000235:genetics*; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D006683:HLA-DQ Antigens / Q000235:genetics; D006684:HLA-DR Antigens / Q000235:genetics; D006239:Haplotypes; D015395:Histocompatibility Antigens Class I / Q000235:genetics*; D006801:Humans; D018895:Microsatellite Repeats / Q000235:genetics; D011110:Polymorphism, Genetic
chemical_list: D006683:HLA-DQ Antigens; D006684:HLA-DR Antigens; D015395:Histocompatibility Antigens Class I; C099187:MHC class I-related chain A