OBJECTIVE: To investigate the relationship between clinical features and the interval between onset of disease in pairs of related Japanese patients with Behçet's disease (BD). METHODS: Questionnaires were sent to hospitals in which patients with familial occurrence of BD had been treated according to previous nationwide hospital surveys, and to an additional 341 hospitals selected at random. RESULTS: A total of 35 patients (19 male, 16 female) in 17 families (19 related pairs) were reported. The positive rate of HLA-B51 was 60.9% (14/23). The familial pairs were divided into 2 groups, with the mean interval between disease onset between each pair being either < or = 9 years or > or = 10 years. Among the short interval group, the total number of clinical findings and difference in age of onset was significantly larger than the long interval group. The interval between onsets had a high positive correlation with concordance of clinical findings and a high negative correlation with the difference in onset age. Difference in onset age had a higher negative correlation with same sex. Moreover, age difference had a high negative correlation with HLA-B5 (B51). Analysis of data showed that the related pairs with the short interval between onsets had larger difference in onset age and greater concordance of symptoms than the long interval patients. CONCLUSION: Although our findings did not show any direct evidence of an environmental cause in the etiology of BD, we speculate that there may be a multifactorial etiology including genetic factors such as HLA-B51 positivity.
OBJECTIVE: To investigate the relationship between clinical features and the interval between onset of disease in pairs of related Japanese patients with Behçet's disease (BD). METHODS: Questionnaires were sent to hospitals in which patients with familial occurrence of BD had been treated according to previous nationwide hospital surveys, and to an additional 341 hospitals selected at random. RESULTS: A total of 35 patients (19 male, 16 female) in 17 families (19 related pairs) were reported. The positive rate of HLA-B51 was 60.9% (14/23). The familial pairs were divided into 2 groups, with the mean interval between disease onset between each pair being either < or = 9 years or > or = 10 years. Among the short interval group, the total number of clinical findings and difference in age of onset was significantly larger than the long interval group. The interval between onsets had a high positive correlation with concordance of clinical findings and a high negative correlation with the difference in onset age. Difference in onset age had a higher negative correlation with same sex. Moreover, age difference had a high negative correlation with HLA-B5 (B51). Analysis of data showed that the related pairs with the short interval between onsets had larger difference in onset age and greater concordance of symptoms than the long interval patients. CONCLUSION: Although our findings did not show any direct evidence of an environmental cause in the etiology of BD, we speculate that there may be a multifactorial etiology including genetic factors such as HLA-B51 positivity.