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Dravet syndrome: Genetics, clinical features, and diagnosis

Authors
Fabio A Nascimento, MD
Danielle M Andrade, MD, MSc, FRCPC.
Section Editor
Douglas R Nordli, Jr, MD
Deputy Editor
April F Eichler, MD, MPH

INTRODUCTION

Dravet syndrome (DS) (OMIM # 607208), previously known as severe myoclonic epilepsy of infancy (SMEI), is a rare early-onset epilepsy syndrome characterized by refractory epilepsy and neurodevelopmental problems beginning in infancy.

DS was first described by Charlotte Dravet in 1978 and was found to have a genetic basis in 2001, with discovery of mutations in the voltage-gated sodium channel, alpha-1 subunit (SCN1A) gene [1,2]. DS is classified as a genetic epilepsy syndrome and an epileptic encephalopathy, defined as an electroclinical syndrome associated with a high probability of encephalopathic features that present or worsen after the onset of epilepsy [3]. (See "ILAE classification of seizures and epilepsy".)

The epidemiology, genetics, clinical features, and diagnosis of DS are reviewed here. Management and prognosis of DS are reviewed separately. (See "Dravet syndrome: Management and prognosis".)

The initial evaluation of febrile and afebrile seizures in infants and children more generally, as well as other epilepsy syndromes of childhood, are reviewed elsewhere. (See "Epilepsy syndromes in children" and "Clinical and laboratory diagnosis of seizures in infants and children" and "Clinical features and evaluation of febrile seizures".)

EPIDEMIOLOGY

Dravet syndrome (DS) is a rare disorder, affecting an estimated 1 in 15,700 to 1 in 40,000 live births [4-6]. It affects males and females in equal proportions [7].

                          

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