Analysis of clinical phenotype and gene variation characteristics of potassium channel gene variation in infants with epileptic encephalopathy

Abstract

Objective To analyze and summarize the clinical and genetic characteristics of potassium channel gene variation in infant epileptic encephalopathy (EE). Methods and Results A total of 11 infants with EE associated with potassium channel gene variation admitted to Hu'nan Children's Hospital from July 2016 to January 2020 were tested by the next generation sequencing (NGS). The variants and their sources were verified by Sanger sequencing. The clinical phenotype included epilepsy of infancy with migrating focal seizures (EIMFS, 4 cases), Ohtahara's syndrome (OS, 2 cases), infantile spasm (IS, 2 cases) and nonspecific EE (3 cases). There were 8 cases of new genetic variation and 3 cases of genetic variation (all from mothers). The variation types were KCNQ2 gene variation (5 cases), KCNT1 gene variation (4 cases) and KCNB1 gene variation (2 cases). Several antiepileptic seizure medicine (ASM) were used in combination therapy, and some of the infants were assisted with ketogenic diet (3 cases). After a mean follow⁃up of 19 months, 3 cases were completely free of seizures, one case was effective, 7 cases were ineffective, and 11 cases were all left with mental retardation and movement disorders. Conclusions Potassium channel gene variation is a common genetic cause of EE in infants, which can cause different clinical phenotypes. Genetic testing can assist in the etiological diagnosis and provide theoretical basis for precise treatment.

doi：10.3969/j.issn.1672⁃6731.2023.03.008