Benign infantile seizures and paroxysmal dyskinesia: a well-defined familial syndrome

The aim of this study was to analyze the electroclinical features and evolution in patients with benign infantile seizures (BIS) associated with paroxysmal dyskinesia (PD).

Among 198 patients with BIS (78 of whom were familial cases), we evaluated 12 unrelated patients with BIS and PD seen at two pediatric neurology departments from January 1990 to February 2009.

The patients were eight boys and four girls, one of whom was not a familial case. The time of follow-up was between 6 and 19 years. Median age at onset of epilepsy was 7 months (R: 5-18 m). Seizures were brief, focal, with or without secondary generalization, and occurred in clusters in 58% of the cases. Seven of 12 patients with BIS and 13 family members had PD. The age at onset of PD was between 5 and 18 years and it was characterized by choreoathetosis in 12 and dystonia in 8. PD was kinesigenic in all cases. As to family history, BIS was found in mothers in two patients, in fathers in five, in a grandfather in one, in grand-uncle in one, in uncles in four, in brothers in three, and in sisters in three other patients. PD was found in fathers in four patients, in the mother in one, in a brother in one, in a cousin in three, in an uncle in one, in an aunt in one, and in grandfathers in two. During follow-up, one patient and a relative with BIS from two different families presented Rolandic epilepsy. The father of the case with BIS and Rolandic epilepsy also had BIS and benign focal seizures of adolescence.

BIS and PD syndrome is a well-defined familial syndrome. BIS had the similar features described in patients with familial and non-familial BIS. The patient with non-familial BIS who developed PD later, suggests that non-familial forms may have a genetic cause and may be caused by de novo mutations.