Epilepsy, Idiopathic Generalized; Eig

Description

Idiopathic generalized epilepsy is a broad term that encompasses several common seizure phenotypes, classically including childhood absence epilepsy (CAE, ECA; see {600131}), juvenile absence epilepsy (JAE, EJA; see {607631}), juvenile myoclonic epilepsy (JME, EJM; see {254770}), and epilepsy with grand mal seizures on awakening (Commission on Classification and Terminology of the International League Against Epilepsy, 1989). These recurrent seizures occur in the absence of detectable brain lesions and/or metabolic abnormalities. Seizures are initially generalized with a bilateral, synchronous, generalized, symmetrical EEG discharge (Zara et al., 1995; Lu and Wang, 2009).See also childhood absence epilepsy (ECA1 ), which has also been mapped to 8q24. Of note, benign neonatal epilepsy 2 (EBN2 ) is caused by mutation in the KCNQ3 gene (OMIM ) on 8q24. Genetic Heterogeneity of Idiopathic Generalized EpilepsyEIG1 has been mapped to chromosome 8q24. Other loci or genes associated with EIG include EIG2 (OMIM ) on 14q23; EIG3 (OMIM ) on 9q32; EIG4 (OMIM ) on 10q25; EIG5 (OMIM ) on 10p11; EIG6 (OMIM ), caused by mutation in the CACNA1H gene (OMIM ) on 16p; EIG7 (OMIM ) on 15q14; EIG8 (OMIM ), caused by mutation in the CASR gene (OMIM ) on 3q13.3-q21; EIG9 (OMIM ), caused by mutation in the CACNB4 gene (OMIM ) on 2q22-q23; EIG10 (OMIM ), caused by mutation in the GABRD gene (OMIM ) on 1p36.3; EIG11 (OMIM ), caused by variation in the CLCN2 gene (OMIM ) on 3q36; EIG12 (OMIM ), caused by mutation in the SLC2A1 gene (OMIM ) on 1p34; EIG13 (OMIM ), caused by mutation in the GABRA1 gene (OMIM ) on 5q34; and EIG14 (OMIM ), caused by mutation in the SLC12A5 gene (OMIM ) on 20q12.

Clinical Features

• Seizures
• Generalized tonic-clonic seizures
• Generalized myoclonic seizures
• Generalized-onset seizure
• Absence seizures
• EEG with spike-wave complexes (>3.5 Hz)