Drug-Resistant Early-Onset Progressive Myoclonic Epilepsy Revealing Lafora Disease: A Case Report.

Lafora disease is a rare, autosomal recessive progressive myoclonic epilepsy characterized by drug-resistant seizures, myoclonus, and cognitive decline. We present the case of a 25-year-old woman with an unusually early onset of epilepsy at three years of age, progressive neurological deterioration, and a positive family history of progressive myoclonic epilepsy. The patient developed multiple seizure types, including generalized tonic-clonic seizures, atonic seizures, and stimulus-sensitive myoclonus, accompanied by progressive cognitive impairment. Electroencephalography (EEG) demonstrated generalized epileptiform discharges with frontocentral predominance and photosensitivity. Brain magnetic resonance imaging (MRI) revealed periventricular and parietal white matter changes with mild white matter reduction, likely related to a perinatal hypoxic-ischemic insult. Despite extensive antiseizure medication polytherapy and vagus nerve stimulation, seizures remained refractory. Although the skin biopsy was negative, the muscle biopsy showed ultrastructural changes consistent with Lafora disease. Genetic testing confirmed a pathogenic mutation in the EPM2B gene, establishing the diagnosis. This case highlights the diagnostic challenges of Lafora disease and the importance of prioritizing genetic testing in early-onset, drug-resistant epilepsy when standard diagnostic evaluations are nondiagnostic.