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Ohtahara syndrome

Also known as: Early Infantile Epileptic Encephalopathy

Background

Ohtahara syndrome is a rare form of childhood epilepsy, which was first described by Ohtahara in 1976. It is one of several severe epilepsy syndromes including West syndrome and Lennox-Gastaut syndrome that have been defined by the age of onset. Seizures often begin in the first ten days of life and usually before the age of three months. Boys are slightly more often affected than girls.

Credits

Medical text written August 2004 by Contact a Family. Approved August 2004 by Professor Brian Neville. Last updated January 2012 by Professor Brian Neville, Emeritus Professor of Paediatric Neurology, UCL Institute of Child Health and Great Ormond Street Hospital, London, UK and Professor H Cross, The Prince of Wales's Chair of Childhood Epilepsy, UCL Institute of Child Health, Great Ormond Street Hospital for Children and Young Epilepsy, UK.

What are the symptoms?

The signs of Ohtahara syndrome are:

  • tonic seizures (stiffening of limbs)
  • psychomotor development delay (delay in development of mental and motor skills)
  • there may development of other neurological difficulties such as:
    • diplegia (paralysis of like parts on either side of the body)
    • hemiplegia (paralysis/weakness of one side of the body)
    • tetraplegia (spasticity and weakness of all four limbs)
    • ataxia (a lack of balance and coordination)
    • dystonia (abnormal movements with increased tone).

What are the causes?

Ohtahara syndrome is most often caused by a developmental abnormality of the brain (also known as a cerebral malformation). The condition occasionally occurs as a result of glycine encephalopathy or other metabolic disorders (see entry Inherited Metabolic diseases). Genetic causes have also recently been reported. It is therefore not a single disease; it is a type of epilepsy with many different causes.

How is it diagnosed?

Ohtahara syndrome is diagnosed by age of onset and type of seizures, and confirmed by an electroencephalogram (EEG), which records the electrical activity of the brain. Children with Ohtahara syndrome show a particular type of electrical activity that alternates between showing spikes and suppression of activity known as 'suppression-burst'.

How is it treated?

There is no cure for Ohtahara syndrome. Treatment helps to reduce the symptoms a child experiences. Control of the seizures is often difficult and the balance of the advantages (extending the times between seizures) and disadvantages (sleepiness, weight gain) of using anticonvulsant drugs such as phenobarbitone needs to be considered. Use of anticonvulsant drugs will not halt the deterioration in psychomotor development. If there is a clear structural brain abnormality on one side causing Ohtahara syndrome then a child should undergo evaluation as to whether this can be removed by surgery, with a chance of resolving or improving seizures.

Children with Ohtahara syndrome often have severe developmental delay and so usually remain totally dependent on others. Sadly, children often die within the first two years of life. Those children that survive beyond two years of life remain severely disabled.

Inheritance patterns and prenatal diagnosis

Inheritance patterns
Often the exact cause Ohtahara syndrome is unknown and can include cerebral malformations, metabolic and direct genetic disorders. All may occur because of genetic predisposition and therefore have a risk of recurrence. Advice from a geneticist should be sought.

Prenatal diagnosis
Prenatal diagnosis may be possible if the type of Ohtahara syndrome is identified as being caused by a genetic disorder.

Is there support?

There is no support group for Ohtahara syndrome in the UK. General support can be obtained from epilepsy support organisations (see entry Epilepsy).

Contact a Family's web-based linking service can be accessed at community.cafamily.org.uk