title: Epilepsies in twins: genetics of the major epilepsy syndromes.
abstract: We studied twins to examine the genetics of epilepsy syndromes. We ascertained 358 twin pairs in whom one or both reported seizures. After evaluation, 253 of 358 (71%) had seizure disorders and 105 pairs were false positives. Among the monozygous (MZ) pairs, more were concordant for seizures (48 of 108; casewise concordance = 0.62 +/- 0.05) than among the dizygous (DZ) pairs (14 of 145; casewise concordance = 0.18 +/- 0.04). In 94% of concordant MZ pairs, and 71% of concordant DZ pairs, both twins had the same major epilepsy syndrome. When analyzed according to major epilepsy syndrome, the casewise concordances for generalized epilepsies (MZ = 0.82; DZ = 0.26), both idiopathic (MZ = 0.76; DZ = 0.33) and symptomatic (MZ = 0.83; DZ = 0), were greater than those for partial epilepsies (MZ = 0.36; DZ = 0.05), with intermediate values seen for febrile seizures (MZ = 0.58; DZ = 0.14) and unclassified epilepsies (MZ = 0.53; DZ = 0.18). We conclude that genetic factors are particularly important in the generalized epilepsies but also play a role in the partial epilepsies. The high frequency of concordant MZ pairs with the same major syndrome strongly suggests there are syndrome-specific genetic determinants rather than a broad genetic predisposition to seizures.
authors.affiliation: Department of Medicine, University of Melbourne, Austin and Repatriation Medical Centre, Heidelberg (Melbourne), Victoria, Australia.
authors.forename: S F
authors.initials: SF
authors.lastname: Berkovic
authors.forename: R A
authors.initials: RA
authors.lastname: Howell
authors.forename: D A
authors.initials: DA
authors.lastname: Hay
authors.forename: J L
authors.initials: JL
authors.lastname: Hopper
mesh_terms: D000704:Analysis of Variance; D001315:Australia; D004200:Diseases in Twins / Q000235:genetics*; D004827:Epilepsy / Q000145:classification / Q000235:genetics*; D005260:Female; D005334:Fever; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D012042:Registries; D012640:Seizures / Q000235:genetics*; D012727:Sex Characteristics; D013577:Syndrome; D014429:Twins, Dizygotic; D014430:Twins, Monozygotic