A case of early epileptic encephalopathy caused by new mutation at W218C in KCNQ2 and review literature

Early-onset epileptic encephalopathy (EOEE) is mainly characterized by early refractory epileptic seizures in infants with progressive brain dysfunction, accompanied by complex causes (such as perinatal brain injury, structural brain malformations and genetic metabolic diseases). Early identification and etiological treatment are critical. It has been reported that mutations in Potassium Voltage-Gated Channel Subfamily Q Member 2 (<i>KCNQ2</i>) can result in EOEE. This study analyzed the genetic defects and clinical phenotypes of a newborn with early epileptic encephalopathy. Whole exome gene detection identified a novel heterozygous point mutation p. W218C in <i>KCNQ2.</i> The pathogenic variant was located in the protein's S4S5 connection region and was identified as a harmful mutation by silico tools. The child's clinical phenotype finally manifested as West syndrome during the follow-up. The mentioned variation may lead to severe clinical manifestations and poor neurological prognosis. Whole exome gene detection provides clinicians with more information on neonatal epileptic encephalopathy.