Incidence of febrile seizure in patients with Down syndrome.

Background: It is unclear whether the incidence of febrile seizure (FS) in children with Down syndrome (DS) is higher or lower than in the general population. In this study, we investigated the incidence of FS in DS patients using mailed questionnaires.

Methods: The questionnaires were distributed to parents or caregivers of DS patients attending Osaka Medical College Hospital and six other facilities. The questionnaires were returned by mail from February 2012 to September 2013 from 323 families of DS patients (176 male, 147 female; age range, 3 months-47 years; median age, 5.0 years). To assess the incidence of FS in DS, we performed the following two analyses: (i) we calculated the incidence of FS among DS patients between the ages of 4 and 20 years (n = 199; 113 male, 86 female), and (ii) we extracted families with both DS and healthy siblings between the ages of 4 and 20 years (n = 150; 77 male, 73 female) and compared the incidence of FS in these sibling groups.

Results: Five DS patients had a past history of FS. The incidence of FS in DS was 2.5%. The incidence of FS was significantly lower in DS patients compared with healthy siblings (P < 0.003; OR, 0.14).

Conclusions: The incidence of FS is lower in DS patients than in the general population.