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.

Australian Twin Registry: 30 Years of Progress

“…Twins can access information about studies, twin resources and events, and register or update contact details. The ATR has an active (Berkovic et al, 1996(Berkovic et al, , 1998Klein et al, 2012;Vadlamudi et al, 2010). Cervical cancer Possible to measure human papilloma virus genotype from archival pap smears (Moore et al, 2012;Tabrizi et al, 2010).…”

A genética das epilepsias

“…5,6 In addition, the risk for relatives of patients with IGE was twice that observed for patients with focal epilepsy. 7,8 These results were confirmed by twin studies in which the concordance rates for monozygotic (MZ) twins were higher as compared to dizygotic (DZ) twins. 9 By contrast, until recently focal epilepsies were widely believed to be nongenetic.…”

“…8 Another study examined the risk, calculating the relative risk (RR) of epilepsy in first degree relatives of 1,498 patients with cryptogenic epilepsy. 8 Risk was significantly elevated in both groups, focal and generalized epilepsy, when compared to the controls. In parents and siblings, the RR was lower if the probands epilepsy was focal (RR =2.4 for focal epilepsy and RR = 4.7 for generalized epilepsy).…”

“…[15][16][17] However, very few of these studies have examined focal epilepsies specifically, or compared focal and generalized epilepsies. Berkovic et al 8 studied the concordance rates for specific epilepsy syndromes in 253 twin pairs in which one or both twins had epilepsy or febrile convulsions. Concordance rates were significantly higher in MZ than in DZ pairs in both generalized (MZ = 82% vs. DZ = 26%) and focal epilepsies (MZ = 36% vs. DZ = 5%).…”

“…It is very interesting to note that despite the widespread assumption of a greater genetic effect on generalized epilepsies, more progress has been made to date in localizing genes for focal epilepsies than for generalized epilepsies. 8 In summary, significant progress has been made in recent years in understanding the genetics of the epilepsies.…”