TSC1 as a Novel Gene for Sleep-Related Hypermotor Epilepsy: A Child with a Mild Phenotype of Tuberous Sclerosis.

Sleep-related hypermotor epilepsy (SHE) is a rare syndrome that presents with hyperkinetic asymmetric tonic/dystonic seizures with vegetative signs, vocalization, and emotional facial expression, mainly during light non-rapid eye movement sleep stages. The role of various genes (CHRNA4, CHRNB2, CHRNA2, KCNT1, DEPDC5, NPRL2, NPRL3, and PRIMA1) has previously been reported, though genetic etiology is assessed in less than 10% of cases. We report the case of a 5-year-old female carrying the TSC1 variant c.843del p.(Ser282Glnfs*36) who presented with a mild phenotype of tuberous sclerosis, including carbamazepine-responsive SHE, normal neurocognitive functioning, hypomelanotic macules, no abnormalities outside the central nervous system, and tubers at neuroimaging. The presented case extends the list of SHE-related genes to include TSC1, thus suggesting a central pathogenic role of mammalian target of rapamycin (mTOR) cascade dysfunction in SHE and introducing a possible use of mTOR inhibitors in this epileptic syndrome.