The GABRD 659 G > A polymorphism may play an important role in the susceptibility of JME and LGS and this polymorphism may also increase the duration of postictal period in JME patients but may decrease the duration of seizure in LGS patients.
Mutations in inhibitory GABAA receptor subunit genes (GABRA1, GABRB3, GABRG2 and GABRD) have been associated with genetic epilepsy syndromes including childhood absence epilepsy (CAE), juvenile myoclonic epilepsy (JME), pure febrile seizures (FS), generalized epilepsy with febrile seizures plus (GEFS+), and Dravet syndrome (DS)/severe myoclonic epilepsy in infancy (SMEI).