Temporal Lobe Epilepsy as the Presenting Feature of Chorea-Acanthocytosis in Two French- Canadian Families

Chorea-acanthocytosis is a neurodegenerative disorder characterized by chorea, tics, orofaciolingual dyskinesia, areflexia, seizures, dementia, and acanthocytosis. Mutations in the CHAC gene encoding for chorein on chromosome 9q21 have been found in both autosomal-dominant and autosomal-recessive CHAC families. We ascertained six individuals in two French-Canadian (FC) families. EEG, video telemetry, magnetic resonance, and volumetric studies were performed. All patients presented with seizures. Age at onset ranged from 22 to 38 years. EEG showed either no or infrequent epileptiform discharges originating independently from both temporal lobes. Epilepsy was initially well controlled, but later all patients had periods of increased seizure frequency. Seizures preceded other clinical manifestations of CHAC by up to 11 years. Abnormal movements worsened with carbamazepine and lamotrigine. Phenytoin and phenobarbital were better tolerated. Acanthocytosis was present in all patients. Both our families, as well as two other FC families, share the same haplotype in the region of the CHAC gene and are homozygous for an exon 70-73 deletion, suggesting a founder effect. Epilepsy in CHAC patients represents a challenge because the seizures may at times be intractable and because anti-epileptic drugs may worsen the involuntary movements.