The clinical significance of Xp22.31 microduplication is still unclear. We describe a family in which a mother and two children have Xp22.31 microduplication associated with different forms of epilepsy and epileptiform EEG abnormalities. The proband had benign epilepsy with centrotemporal spikes with dysgraphia and dyscalculia (IQ 72), the sister had juvenile myoclonic epilepsy, and both had bilateral talipes anomalies. The mother, who was the carrier of the microduplication, was asymptomatic. The asymptomatic father did not possess the microduplication. These data contribute to delineate the phenotype associated with Xp22.31 microduplication and suggest a potential pathogenic role for an epilepsy phenotype.