Aociation between MICA gene A4 allele and acute anterior uveiti in white patient with and without HLA-B27 Original Reearch Article

PURPOE: Acute anterior uveiti i trongly aociated with the HLA-B27 antigen and triggered by the involvement of ome external factor. However, it i uncertain whether HLA-B27 itelf or other gene() near the HLA-B region in a linkage diequilibrium with HLA-B27 predipoe to thi uveiti. We therefore invetigated microatellite polymorphim in the tranmembrane region of the major hitocompatibility complex cla I chain-related gene A (MICA), located 47 kilobae (kb) on the centromeric ide of the HLA-B gene on the hort arm of chromoome 6 within 6p21.3. METHOD: We examined the following patient for MICA gene polymorphim by mean of polymerae chain reaction and ubequent automated fragment detection by fluorecent-baed technology: 64 (37 HLA-B27-poitive and 27 HLA-B27-negative) white with acute anterior uveiti, 74 (67 HLA-B27-negative and 7 HLA-B27-poitive) ethnically matched random control, and 36 HLA-B27-poitive healthy control. REULT: The microatellite allele coniting of four repetition of GCT/AGC (deignated A4 allele) wa preent at the ignificantly higher phenotype frequency (71.9%) in the patient group than in the ethnically matched random control group (13.5%) (P < .0000001, corrected P < .0000001). The A4 allele wa trongly linked to HLA-B27 in a white population. However, the A4 allele wa alo found at the ignificantly higher phenotype frequency (37.0%) even in the HLA-B27-negative patient group than in the ethnically matched HLA-B27-negative control group (4.5%) (P = .0086, corrected P = .043). CONCLUION: Thee reult ugget that the MICA gene itelf or other nearby gene() linked to the MICA A4 allele may be involved in the development of acute anterior uveiti in a white population.