Analysis of a family with inherited generalized epilepsy with febrile seizures plus caused by the KCNT2 mutation and literature review / 中华实用儿科临床杂志

ABSTRACT

Objective:To explore the clinical characteristics and treatment of a family with inherited generalized epilepsy with febrile seizures plus (GEFS + ) caused by the KCNT2 gene mutation and review the literature. Methods:Clinical data of a child with GEFS + and his family members who visited Department of Pediatric Neurology, Guangzhou Women and Children′s Medical Center in May 2019 were collected.DNA samples were collected from the peripheral blood of the proband, his parents, his elder brother, and his maternal grandparents, and genetic analysis and verification were performed using the next-generation sequencing technique.Using " KCNT2" as the key word, literature was retrieved from PubMed, China National Knowledge Infrastructure and Wanfang databases (up to August 2019). Results:The proband was a 3-year-old boy who was admitted to Guangzhou Women and Children′s Medical Center because of frequent epileptic seizures in the past 5 months.He presented with a binocular gaze and experienced 3 to 8 times of extremities myoclonic-spastic epileptic attacks every day.He had a history of 3 times of febrile seizures at the age of 2 years old.His seizures were refractory to Sodium valproate, Topiramate, Nitrazepam and Levetiracetam.His elder brother and mother had a history of childhood febrile seizures.Other members in the family had no history of convulsion.Ictal electroencephalogram showed general 1 Hz high voltage spike-slow waves.A heterozygous nonsense mutation of KCNT2 gene c. 574C>T(p.Q192X) that was never reported previously was detected in the proband, his brother, mother and maternal grandmother.Furthermore, no other family members carried the mutation at the c. 574 locus of the KCNT2 gene.No article in Chinese was found, and 2 articles in a language other than Chinese provided the complete data of 3 sporadic cases.Together with 4 cases in the family studied in this article, there were 7 cases and 4 mutation sites in KCNT2 gene.Of these mutations, there were 3 missense mutations and 1 nonsense mutation.Three sporadic patients presented with early infantile epileptic encephalopathy.The family of this study was characterized with febrile seizures and febrile seizures plus. Conclusions:A de novo mutation and phenotype of the KCNT2 gene is found in a family with GEFS + .It would expand the gene mutation spectrum and provide basis for family genetic counseling. KCNT2 mutation induced GEFS + is refractory to antiepileptic drugs.