Familial occurrence of early-onset childhood absence epilepsy.

Early onset of absence seizures (<3 years) is rare and usually associated with a poor cognitive prognosis. Familial cases have not been reported to date. We observed a family in which two out of three sibs showed early-onset absences and mild mental retardation. Linkage to the ECA1 locus, where one clinical subtype of CAE is mapped, was excluded by haplotype analysis. Direct sequencing of the candidate genes CLCN2 ,GABRG2 and CHRNA4 showed no mutations. We suggest the possibility of a specific epileptic syndrome with a putative AR inheritance. Further report of affected patients might allow a better classification.