The Characteristics and Long-Term Course of Epilepsy in Lipoid Proteinosis: A Spectrum From Mild to Severe Seizures in Relation to ECM1 Mutations

Lipoid proteinosis (LP) is a rare autosomal recessive disease characterized by deposition of hyaline material in skin and mucosae. Epilepsy, as an extracutaneous manifestation associated with typical mesial temporal calcifications, has already been identified, but its characteristics and long-term prognosis have not been thoroughly investigated. We included 7 consecutive patients with LP with typical intracranial calcifications out of 16 patients with ECM1 mutations and investigated the semiologic features, ictal and interictal EEG findings, and long-term prognosis of epilepsy in this genodermatosis. Four of them had seizures (57.1%), and focal seizures with motionless staring were the most common seizure phenotype, originating from bilateral mesial temporal areas, but interictal spikes were scant. Auras were observed in three patients, mostly as epigastric sensation and déjà vu, which indicated mesial temporal lobe origin. Three patients with homozygous mutations in sixth and seventh exons of the ECM1 gene had a drug-resistant course at the end of long-term follow-up. Molecular genetic testing showed a rare compound heterozygous mutation in one patient, which was also associated with seizures but without drug-resistance. Our findings indicated a spectrum for epilepsy with a desperate drug-resistant course for decades in most patients with LP, which is still an underrecognized disease by neurologists.