Autism in Dravet syndrome: Prevalence, features, and relationship to the clinical characteristics of epilepsy and mental retardation

Autism is a pervasive developmental disorder that frequently co-occurs with epilepsy. Dravet syndrome is a severe epileptic encephalopathy associated with psychomotor developmental delay. Autism in Dravet syndrome, however, has rarely been studied. In this study, the prevalence and features of autism in patients with Dravet syndrome, their potential association with mental retardation, and the clinical characteristics of epilepsy were investigated. Clinical data of 37 patients with Dravet syndrome were collected, and evaluations of autism and mental retardation were performed. Nine patients (24.3%) met the criteria for autism. All patients with autism showed speech delay, no emotional reciprocity, and narrow interests, whereas 89.3, 46.4, and 39.9% of patients without autism had speech delay, short temper, and narrow interests, respectively. Mental retardation was observed in 94.6% of patients with Dravet syndrome, with more frequent severe or profound mental retardation in those with autism. The clinical features of epilepsy did not statistically differ between the patients with autism and the patients without autism.

Research highlights
► The prevalence and features of autism in patients with Dravet syndrome are assessed.
► The majority of patients with Dravet syndrome exhibit some symptoms of autistic spectrum disorder.
► Patients with Dravet syndrome with autism exhibit more severe mental retardation.
► This is the first clinical study demonstrating autism in Dravet syndrome.