A 38-year-old man with recurrent bilateral tonic–clonic seizures since 2018 presented in January 2025 for further evaluation. His seizures occurred 1–2 times per month and were commonly precipitated by sleep deprivation or exposure to cold water. Episodes were accompanied by tongue biting, post-ictal confusion, and amnesia. He had no significant medical or family history, and neurological examination was unremarkable. MRI of the brain demonstrated nodular subcortical grey-matter heterotopia adjacent to the right putamen and a similar lesion in the left corona radiata. The EEG recorded during wakefulness was normal. Laboratory tests were notable only for elevated total cholesterol. Findings were consistent with focal epilepsy secondary to subcortical grey-matter heterotopia.