Association of a 9.2‐kilobase pvu ii class i major histocompatibility complex restriction fragment length polymorphism with ankylosing spondylitis

Abstract

We analyzed DNA restriction fragment length polymorphism (RFLP) in 53 white ankylosing spondylitis (AS) patients and 92 healthy controls, utilizing a full-length HLA-B7 complementary DNA probe. A 9.2-kilobase (kb) Pvu II fragment was found to be significantly increased in frequency in B27 positive AS patients compared with the B27 positive control group (P = 0.00085, relative risk = 7.2). The presence of both B27 and the 9.2-kb RFLP in an individual conferred a relative risk for AS of 297, compared with a relative risk of 119 in those who had B27 alone. The 9.2-kb RFLP appears to be a marker for AS which, with HLA–B27, contributes further to susceptibility to the disease. Our findings indicate that this fragment and HLA–B27 segregate independently in familial studies of AS.