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generalized epilepsy with febrile seizures

MIM.604233

Tuesday 22 April 2008

Generalized epilepsy with febrile seizures-plus is a group of five epilepsy syndromes of variable phenotypes but typically including simple febrile seizures, generalized seizures usually precipitated by fever after age 6 years, and partial seizures.

In generalized epilepsy with febrile seizures-plus type 1, the mutated gene is SCN1B, located on chromosome 19q, encoding for the voltage-gated sodium channel beta-1 subunit.

Generalized epilepsy with febrile seizures-plus type 2 is caused by mutations of the SCN1A gene located on chromosome 2q, encoding for the alpha-1 subunit of the same sodium channel.

Generalized epilepsy with febrile seizures-plus type 3 and generalized epilepsy with febrile seizures-plus type 5 are caused by mutations of either the GABRG2 gene on chromosome 5q or the GABRD gene on chromosome 1, respectively. Both genes encode subunits of the GABAA receptor, which is associated with the chloride channel.

The specific age for this subtype has not yet been identified. Generalized epilepsy with febrile seizures-plus type 4 was linked to chromosome 2p24, but the underlying gene or channel has not been identified.

Etiology

The GEFS phenotype may be caused by mutation in several genes.

- voltage-gated sodium channel beta-1 subunit gene (SCN1B) (MIM.600235) on 19q13 causes GEFS+ type 1.

- SCN1A gene (MIM.182389) on 2q24 causes GEFS+ type 2.

- GABRG2 gene (MIM.137164) on 5q31.1-q33.1 causes GEFS+ type 3.

- GABRD (MIM.137163) gene can cause GEFS+ type 5.

- SCN2A (MIM.182390) gene causes febrile seizures associated with afebrile seizures.

See also

- channelopathies

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