For a general phenotypic description and a discussion of genetic heterogeneity of idiopathic generalized epilepsy, see 600669. Juvenile myoclonic epilepsy is a subtype of idiopathic generalized epilepsy; see 254770 for a general phenotypic description and a discussion of genetic heterogeneity of JME.

Juvenile absence epilepsy is a subtype of idiopathic generalized epilepsy (IGE; see 600669). Manifestations occur around puberty, in contrast to childhood absence epilepsy (CAE; 600131), which begins at age 6 to 7 years. Absence seizures, generalized tonic-clonic seizures (GTCS), GTCS on awakening, and myoclonic seizures are the main features of JAE. (Commission on Classification and Terminology of the International League Against Epilepsy, 1989). Genetic Heterogeneity of Juvenile Absence Epilepsy See also susceptibility to juvenile absence epilepsy-2 (EJA2; see 607628), conferred by variation in the CLCN2 gene (600570) on chromosome 3q26.

Both juvenile myoclonic epilepsy and juvenile absence epilepsy are subtypes of idiopathic generalized epilepsy (EIG). For a general phenotypic description and a discussion of genetic heterogeneity of these disorders, see EIG1 (600669), EJM1 (254770), and EJA1 (607631).