Based on our proband and a recently described group of families with benign familial infantile epilepsy and SCN8A variant we suggest expanding testing to patients with infantile epilepsy and no cognitive impairment.
The phenotypes of the heterozygous individuals suggest that mutations in SCN8A may result in motor and cognitive deficits of variable expressivity, but the study was limited by lack of segregation in the small pedigree and incomplete information about family members.