Children with familial cryptogenic epilepsy have a favorable seizure prognosis.

We examined the prognosis for children with epilepsy not conforming to a genetic syndrome, who also had close relatives with epilepsy. Probands, with no identified cause for epilepsy except a first-degree relative with epilepsy, were identified from a population-based cohort of 504 children in Nova Scotia, with onset of seizures between 1977 and 1985. The primary outcome measure was seizure remission after an average of 15 years follow-up for probands (n = 27) and 26 years for their affected relatives (n = 32). Of probands, 92% were seizure free for 3 or more years at the end of follow-up, compared with 76% of relatives. When seizures began before age 12 years, 96% of probands and 94% of affected relatives were seizure free at the end of follow-up. There was little concordance for the details of the clinical course between probands and affected family members. This high level of remission was considerably better than for similar patients from the original Nova Scotian cohort (P < .02). We conclude that children with epilepsy not conforming to a well-defined genetic syndrome, but with an affected first-degree relative, have a remarkably good prognosis.