GATOR1 variants in Chinese people with sporadic drug-resistant focal epilepsy.

OBJECTIVES: GATOR1 (Gap Activity TOward Rags 1) is composed of three different subunits, DEPDC5 (DEP domain-containing protein 5), NPRL2 (nitrogen permease regulator-like 2), and NPRL3 (nitrogen permease regulator-like 3), and variants in these three genes have mostly been reported in familial focal epilepsy. However, very few studies have been carried out on sporadic drug-resistant focal epilepsy patients. In this study, we aimed to identify the frequency of variants in DEPDC5, NPRL2 and NPRL3 in patients with sporadic drug-resistant focal epilepsy.

MATERIALS & METHODS: One hundred and ninety-three Chinese people with sporadic drug-resistant focal epilepsy were enrolled in the study. Targeted sequencing of DEPDC5, NPRL2 and NPRL3 was applied at an average coverage depth of 2500x.

RESULTS: In the 193 patients with sporadic focal epilepsy included in this study, the median age was 24.6 years with a median age at onset of 13.99 years, and 130 of these patients had identifiable structural lesions. One possibly pathogenic missense variant of DEPDC5, c.2984G>A, p.Arg995His, was found in one patient (0.52%) with hippocampal sclerosis, and one variant of unknown significance, DEPDC5 c.20A>G, p.Tyr7Cys, was found in two patients with hippocampal sclerosis (1.04%).

CONCLUSIONS: Our findings suggested that DEPDC5 might be of more importance than NPRL2 or NPRL3 in Chinese epilepsy patients with sporadic drug-resistant focal epilepsy. Future research should focus on the mechanism by which the mechanistic target of rapamycin (mTOR) is involved in epileptogenesis in sporadic epilepsy. This article is protected by copyright. All rights reserved.