A study of familial occurrence of Behçet's disease with and without ocular lesions.

PURPOSE To examine retrospectively the features of Behçet's disease patients with familial occurrence and make a comparison between familial Behçet's patients with ocular lesions and those without ocular lesions. METHODS We sent questionnaires about Behçet's disease patients with familial occurrence to 114 hospitals that reported treating such patients in previous nationwide hospital surveys, and to 341 hospitals selected at random in Japan. RESULTS We obtained reports on 83 Behçet's patients with familial occurrence. The positive rate of HLA-B51 was 53.1%. The positive rate of HLA-B51 among patients with ocular lesions was 64.0%, that in patients without ocular lesions was 14.3%, and that in patients with genital ulcers was 40.9%. The mean birth year and onset year of the patients with ocular symptoms was significantly lower than that of the patients without ocular symptoms. Although there was no significant difference between these two groups, parent-child involvement was more common among the patients without ocular lesions than in those with ocular lesions. CONCLUSIONS The findings of this study suggest that the number of familial Behçet's disease patients with ocular lesions and high HLA-B51 positivity has been decreasing recently. To elucidate the etiology of familial occurrence, larger scale epidemiological studies and further molecular studies of Behçet's disease are needed.