title: The frequency of QAP2.1 is increased in psoriasis vulgaris patients but no unusual linkage between QAP/DQA1 or QBP/DQB1.
abstract: Psoriasis vulgaris is a chronic skin disease with a genetic and immunological background. We have previously defined the two most frequent risk haplotypes in Finns: A2,B13,Cw6,DR7,DQA1*0201 and A1,B17,Cw6,DR7,DQA1*0201. The aim of this study was to further examine whether the flanking regions, URRs of DQ (QAP and QBP) and TAP1 and TAP2 genes are involved in susceptibility to psoriasis. The frequency of QAP2.1 was increased in psoriatics as compared with controls (Pc = 3.6 x 10(-2), RR = 5.0), and the frequency of QAP4.1 was decreased in psoriasis patients (Pc = 4.2 x 10(-2)). The frequency of the phenotype combination Val/Ile at position 379 of TAP2 was decreased in patients (Pc = 1 x 10(-2)). The allele and phenotype frequencies of TAP1 and TAP2 genes were not different between these groups. Haplotypes A2, B13,Cw6,DR7,DQA1*0201,QAP2.1 and A1,B17,Cw6, DR7,DQA1*0201,QAP2.1 are the two most frequent HLA marker haplotypes for psoriasis vulgaris in Finns, Cw6, DR7, DQA1*0201 and QAP2.1 being the most important single alleles for the risk of this disease.
authors.affiliation: Department of Medical Microbiology, University of Oulu, Finland.
authors.forename: I
authors.initials: I
authors.lastname: Ikäheimo
authors.forename: S
authors.initials: S
authors.lastname: Silvennoinen-Kassinen
authors.forename: J
authors.initials: J
authors.lastname: Karvonen
authors.forename: A
authors.initials: A
authors.lastname: Tiilikainen
mesh_terms: D000071181:ATP Binding Cassette Transporter, Subfamily B, Member 2; D000071450:ATP Binding Cassette Transporter, Subfamily B, Member 3; D018528:ATP-Binding Cassette Transporters / Q000235:genetics; D008040:Genetic Linkage; D006683:HLA-DQ Antigens / Q000235:genetics*; D006684:HLA-DR Antigens / Q000235:genetics; D006801:Humans; D011565:Psoriasis / Q000235:genetics*
chemical_list: D000071181:ATP Binding Cassette Transporter, Subfamily B, Member 2; D000071450:ATP Binding Cassette Transporter, Subfamily B, Member 3; D018528:ATP-Binding Cassette Transporters; D006683:HLA-DQ Antigens; D006684:HLA-DR Antigens; C073119:TAP1 protein, human; C071692:TAP2 protein, human