PITTSBURGH—Important genetic influences may contribute to mental retardation and epilepsy in children, especially in the absence of a defined cause, according to Peter Camfield, MD, and Carol Camfield, MD. They presented their findings at the 35th Annual Meeting of the Child Neurology Society.

The researchers sought to determine the causes of childhood epilepsy associated with mental retardation. They analyzed data from 692 children who were part of the Nova Scotia Childhood Epi-lepsy Cohort. Family history and causes of epilepsy for each patient were determined after a mean of almost 20 years.

"Although etiologies have been described for many of the epilepsy syndromes and also for mental retardation, no other population-based studies or large case series have put these two entities together," Dr. Peter Camfield, a Professor of Pediatrics at Dalhousie University in Halifax, Nova Scotia, told Neurology Reviews. A total of 147 children (21%) had both epilepsy and mental retardation, and the origin of epilepsy was pinpointed in 63% of cases. In subjects with severe mental retardation, there was a defined etiology for epilepsy in about 76% of cases, versus 49% of mild cases of mental retardation. Of the 93 cases in which a cause was established, 64.5% were categorized as prenatal or genetic, 7.5% as perinatal, 12.9% as a result of complications of premature birth, and 15% as postnatally acquired. Eleven cases were determined to have been potentially preventable. In addition, 52 subjects had a first- or second-degree relative with epilepsy. Positive family history was found in 46% of those whose cause of epilepsy was unknown, versus 29% of patients for whom cause was known.

"[We want to] encourage understanding that most of these terrible problems cannot be prevented at the current time," commented Dr. Peter Camfield. But he hopes further studies will focus on more detailed neuroimaging, which is "likely to help give a more specific diagnosis for some of those [cases] that are now cause-unknown."

NR