Clinical features of patients with Kawasaki disease whose parents had the same disease.

OBJECTIVE To observe the clinical characteristics of patients with Kawasaki disease whose parent also had the same disorder. DESIGN Cross-sectional study using the data from nationwide surveys of Kawasaki disease in Japan. SETTING All hospitals with a bed capacity of 100 or more and pediatric departments in Japan. PATIENTS All patients described on the 16th and 17th surveys covering the 4-year period from January 1, 1999, through December 31, 2002. MAIN OUTCOME MEASURES We compared clinical details, including sibling case, recurrence, diagnosis, administration of intravenous immunoglobulin, and coronary abnormalities, between patients whose parents had Kawasaki disease and patients with no parental history of Kawasaki disease. We also observed age at onset and sex of affected parent-offspring pairs with Kawasaki disease confirmed by using the data of previous nationwide surveys. RESULTS The odds for having sibling cases were significantly increased among patients whose parents also had Kawasaki disease (odds ratio, 6.94; 95% confidence interval, 2.77-17.38). Patients with parental Kawasaki disease were more likely to experience recurrent Kawasaki disease, receive additional administration of intravenous immunoglobulin, and experience coronary abnormalities at 1 month after onset. Among confirmed parent-offspring pairs with Kawasaki disease, the mean age at onset of offspring was younger than that of their parents (25.6 vs 41.8 months), despite the lack of statistical significance. CONCLUSIONS Some cases of Kawasaki disease show familial susceptibility to the disorder. Family history, especially parental history of Kawasaki disease, may be an indicator of disease severity.