title: Predisposition to idiopathic thrombocytopenic purpura maps close to the major  histocompatibility complex class I chain-related gene A.
abstract: Idiopathic thrombocytopenic purpura (ITP) is an autoimmune condition with poorly known etiology, characterized by platelet destruction. Genetic association studies of this disease are scarce, discrepant, and restricted to major histocompatibility complex (MHC) polymorphisms. Hence, a case-control study was conducted with an aim to map the MHC to IPT susceptibility using HLA-B and nine microsatellite loci encompassing MHC class I, II, and III regions. We compared the allelic frequencies in samples of unrelated healthy controls and ITP patients. After correction for multiple tests, only allele MICA*183, also known as A5.1, demonstrated an association, resulting in the identification of a major predisposing region close to STR-MICA. This result may highlight the putative functional role of MICA in the immune response to ITP.
authors.affiliation: Laboratório de Genética Humana e Médica, Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, PA, Brasil. mariahtmaia@gmail.com
authors.forename: Maria Helena Thomaz
authors.initials: MH
authors.lastname: Maia
authors.forename: Raquel de Lima
authors.initials: Rde L
authors.lastname: Peixoto
authors.forename: Clayton Pereira Silva
authors.initials: CP
authors.lastname: de Lima
authors.forename: Milena
authors.initials: M
authors.lastname: Magalhães
authors.forename: Leonardo
authors.initials: L
authors.lastname: Sena
authors.forename: Perpétua do Socorro Silva
authors.initials: Pdo S
authors.lastname: Costa
authors.forename: Fabíola Brasil
authors.initials: FB
authors.lastname: Barbosa
authors.forename: Layanna Freitas
authors.initials: LF
authors.lastname: de Oliveira
authors.forename: Matilde
authors.initials: M
authors.lastname: Romero
authors.forename: Christina Nogueira de Araujo
authors.initials: CN
authors.lastname: Silva
authors.forename: Eduardo José Melo
authors.initials: EJ
authors.lastname: dos Santos
mesh_terms: D000328:Adult; D001323:Autoantibodies; D001938:Brazil; D016022:Case-Control Studies; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D015235:HLA-B Antigens / Q000235:genetics / Q000276:immunology*; D015395:Histocompatibility Antigens Class I / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D008297:Male; D018895:Microsatellite Repeats / Q000276:immunology; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000276:immunology; D019038:Platelet Glycoprotein GPIb-IX Complex / Q000276:immunology; D016553:Purpura, Thrombocytopenic, Idiopathic / Q000235:genetics* / Q000276:immunology* / Q000503:physiopathology
chemical_list: D001323:Autoantibodies; D015235:HLA-B Antigens; D015395:Histocompatibility Antigens Class I; C099187:MHC class I-related chain A; D019039:Platelet Glycoprotein GPIIb-IIIa Complex; D019038:Platelet Glycoprotein GPIb-IX Complex; C032193:glycoprotein receptor GPIb-IX