Epilepsies among twins born in families of Indian probands with epilepsy.

Twins have a high frequency of adverse perinatal events and have been reported to have an increased risk of seizures. Contrary to popular belief, a recent study reported that twins do not have an increased risk of seizures. We studied the relationship of twinning and epilepsy in India. The frequency of twinning in families of probands with epilepsy was compared with the frequency of twinning among hospital births in the same region of India. We also compared consecutively ascertained probands with epilepsy for their twin status and the occurrence of epilepsies in their twin and non-twin relatives. The frequency of twin births in families of 524 probands with epilepsy was comparable to the twin births among consecutive deliveries over a 3-year period in another government hospital in the same catchment area (1:99 vs. 1:75). Every 1 in 58 of probands with epilepsy was a twin while a twin was born in these families every 1 in 71 live births. The frequency of epilepsy in non-proband twin relatives was 1.5% compared with 2% among non-proband, non-twin relatives. This data suggests that twin birth is not a major risk factor for seizures even in families of Indian probands with epilepsy. Family data such as ours can be used to study the contribution by genetic factors in the pathogenesis of complex genetic diseases such as human epilepsies.