Familial aggregation in Behcet's disease: High frequency in siblings and parents of pediatric probands

Objective: To examine familial aggregation of Behcet's disease (BD) in pedi atric compared with non-pediatric patients. Methods: A retrospective study was conducted to analyze data collected from 572 patients with ED in whom the diagnosis was made with criteria defined by the International Study Group for ED. The age of attaining criteria (the age at which the patient met the study group criteria) was evaluated for e ach patient. Recurrence risks were calculated for the pediatric group from information provided by 45 families. Results: Of the 505 patients from whom the age of attaining criteria could be ascertained, 106 showed definitive ED before the age of 16 years and wer e considered as pediatric patients with ED; the other 399 were classified a s non-pediatric patients. Thirteen of the 106 pediatric patients (12.3%) an d only 9 of the 399 non-pediatric patients (2.2%) had relatives affected by ED. This excess of familial cases in the pediatric group compared with the non-pediatric group was significant (P < .0001, chi(2) analysis). Moreover , the mean age of attaining criteria in familial cases (17.95 years [SD = 8 .62]) was significantly lower than in sporadic cases (27.28 years [SD = 11] ; P < .0001, Student t test). The recurrence risk among siblings and parent s who met the International Study Group criteria was 0.1. Conclusion: Our data support the hypothesis of a genetic component in the p athogenesis of ED, and we propose the inclusion of familial history in the definition of pediatric ED.