Dravet syndrome

Also known as: Severe Myoclonic Epilepsy of Infancy


Dravet syndrome is a rare and severely disabling type of childhood epilepsy. The condition was first described in 1978 by Charlotte Dravet. It affects about 1 in 40,000 children.


Medical text written by Contact a Family February 2010. Approved February 2010 by Professor Brian Neville, Emeritus Professor of Paediatric Neurology, UCL Institute of Child Health and Great Ormond Street Hospital, London, UK.

What are the symptoms?

The early seizures in the first year consist of clonic (jerking) movements, which often affect one side of the body and are prolonged. A total of 75 per cent of seizures are provoked by fever and this may follow immunisation, which is regarded as a non-specific trigger. Development during the first year of life is usually normal, but following this a range of seizures appear which include:

  • myoclonic jerks, single or multiple muscle jerks, which may involve one part of the body or the whole body
  • atypical absences with brief loss of awareness
  • partial seizures, which may involve loss of awareness
  • non-convulsive status where the child develops a groggy, poorly functional state.

Sometime from the second year developmental slowing or regression occurs, which is often but not invariably severe. Features of autism (see entry Autism Spectrum conditions) and attention deficit hyperactivity disorder are common.

A movement problem of the legs commonly appears with signs of spasticity (muscle tightness) and unsteadiness.

Mild variants of this condition are occasionally seen.

What are the causes?

About 80 per cent of patients with Dravet syndrome have various mutations in a sodium channel gene, SCN1A, and in rare cases a GABA gene defect is found (GABRG2).

How is it diagnosed?

The diagnosis of Dravet syndrome is essentially clinical, based upon the evolution of typical seizures and developmental regression. The presence of the gene defect is strongly supportive evidence but not required for diagnosis and can be associated with other types of epilepsy including generalised epilepsy with febrile seizures plus (GEFS+).

How is it treated?

Anti-epileptic drugs are used but often not effective. Stiripentol has been advocated, usually combined with a benzodiazepine and/or sodium valproate. Comprehensive assessment and provision is required for the multiple impairments associated with Dravet syndrome.

Inheritance patterns and prenatal diagnosis

Inheritance patterns
Familial occurrence is rare and most are due to a new mutation.

Prenatal diagnosis
This can only be discussed in rare familial situations.

Is there support?

Dravet Syndrome UK

Tel: 08443 321 008
Email: info@dravet.org.uk
Website: dravet.org.uk

The Group in a Registered Charity in England and Wales No. 1128289. It provides emotional, practical and financial support for families affected by Dravet Syndrome. The Group funds medical research into Dravet Syndrome and other related genetic sodium channel epilepsies, and raises awareness and understanding of the condition within the professional community.

Group details last updated October 2015.


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