Analyzing the data about relationship between JIA type and HLA B27 allele type, credibly positive association has arthritis with enthesitis with *2705 type (OR = 2.01, p < 0.02), polyarthritis with *2717 (OR = 3.0, p < 0.05) and oligoarthritis with *2710 type (OR = 3.0, p < 0.04). The gene discussed is MRAP; the disease is polyarticular arthritis.