Genotype and phenotype analysis using an epilepsy-associated gene panel in Chinese pediatric epilepsy patients

Epilepsy is a common and genetically heterogeneous disorder among children. Advances in next-generation sequencing have revealed that numerous epilepsy genes, helped us improve the understanding of mechanisms underlying epileptogenesis, and guided the development of treatments. We identified 39 candidate variants in 21 genes, including 37 that were pathogenic or likely pathogenic variants according to the American College of Medical Genetics and Genomics scoring system and two variants of uncertain significance that were considered causative after they were associated with clinical characteristics. Thirty were de novo variants (76.9%), and 20 variants had not previously been reported (51.3%). We obtained a diagnosis in 39 of the 141 probands (27.7%). The most frequently mutated gene was SCN1A; KCNQ2, KCNT1, PCDH19, STXBP1, SCN2A, TSC2, and PRRT2 were mutated in more than one individual; ANKRD11, CDKL5, DCX, DEPDC5, GABRB3, GRIN2A, IQSEC2, KCNA2, KCNB1, KCNJ6, TSC1, SCN9A, and SCN1B were mutated in a single individual. In addition, we detected a nonsense variant in a candidate gene KCND1 and considered it as a new candidate epilepsy gene, which needed further functional study. Consequently, large number of unreported variants were detected, diverse phenotypes were associated with known epilepsy genes. Changes in clinical management beyond genetic counseling were suggested.