A familial study of the inheritance of HLA-B27-positive acute anterior uveitis.

To determine whether factors besides HLA-B27 play a pathogenic role in acute anterior uveitis, we examined 152 first-degree relatives of 42 randomly selected HLA-B27-positive acute anterior uveitis patients. Nine relatives, all from different families, had acute anterior uveitis: eight were HLA-B27 positive and one was HLA-B27 negative. The prevalence of acute anterior uveitis in HLA-B27-positive first-degree relatives of HLA-B27-positive acute anterior uveitis patients was 13% (eight of 63). This is significantly more (P less than .0001) than the frequency of 1% in the normal HLA-B27-positive Dutch population. Ankylosing spondylitis was found in four of 38 (11%) HLA-B27-positive family members over the age of 45 years. This is also significantly more than the prevalence of 1% in a normal HLA-B27-positive Dutch population. Of these four relatives with ankylosing spondylitis, three also had acute anterior uveitis. It was remarkable that two of these four relatives had a proband who had no ankylosing spondylitis.