Crisis-like Seizure Exacerbations in NPRL3-related Epilepsy: Phenotypic Features and Treatment Outcomes

NPRL3 (nitrogen permease regulator-like 3) variants are associated with focal epilepsy syndromes, including sleep-related hypermotor epilepsy (SHE) and familial focal epilepsy with variable foci (FFEVF), with or without focal cortical dysplasia (FCD). The NPRL3 gene encodes a protein that forms the GATOR1 complex, which regulates the mTOR signaling pathway.To characterize the epilepsy phenotype associated with NPRL3, assess treatment strategies, and evaluate patient prognosis.We conducted a multicenter, retrospective study using an online questionnaire to collect clinical data on seizure onset, crisis-like seizure exacerbations, MRI findings, neuropsychological assessment, treatment, and genetic variants. Variants were classified per ACMG guidelines. The study was part of the Network for Therapy in Rare Epilepsies (NETRE).Data from 37 patients with NPRL3-associated epilepsy were analyzed. Mean age at seizure onset was 3.7 years (median with interquartile range [IQR] 1.3-4.9). Over 1 to 45 years of follow-up (mean 13.6, IQR 5.4-18), 21/37 (57%) experienced crisis-like seizure exacerbations. MRI abnormalities were present in 10/36 (28%) cases: 8 FCD, 1 hippocampal sclerosis, and 1 hippocampal asymmetry. Persistent focal epileptiform discharges were present on serial EEGs in 20/37 patients (54%). Highest drug response rates were seen with lacosamide, followed by clobazam, carbamazepine/oxcarbazepine, and lamotrigine. Epilepsy surgery (n = 8) led to seizure freedom in four and significant reduction in one case.Crisis-like seizure exacerbations were common in NPRL3-associated epilepsy. Sodium channel blockers showed notable efficacy. Epilepsy surgery was beneficial even in MRI-negative cases. No distinct genotype-phenotype correlation was identified.