New phenotype of severe neonatal episodic laryngospasm due to a missense mutation in SCN4A: A case report and literature review

VernacularTitle:由SCN4A基因错义突变导致的严重新生儿发作性喉痉挛1例及文献复习
Author: Qiong XI ¹ ; Lu YI ; Wenjuan ZHOU ; Jia CHEN ; Zuocheng YANG
Author Information

1. 中南大学湘雅三医院儿科,长沙410013
Keywords: SCN4A gene; channelopathy; myotonia; sodium channel
From: Journal of Central South University(Medical Sciences) 2021;46(12):1430-1436
CountryChina
Language:Chinese
Abstract: Severe neonatal episodic laryngospasm (SNEL) is an ion channel disease characterized by recurrent life-threatening myotonia of respiratory muscle due to mutations in the voltage-gated sodium channel genes. Here we reported a newborn manifested as paroxysmal cyanosis and limb myotonia after birth. The neonate also developed muscle hypertrophy and stunted growth during the follow-up. Whole exome sequencing confirmed c.2395G>A, p. Ala799Thr heterozygous mutation of SCN4A. Carbamazepine was found to be effective on treating the disease. This case expands our understanding of the phenotype resulting from SCN4A mutations. By summarizing the characteristics of reported 16 cases in SNEL, we found they were mainly in the p.G1306E mutation. The common symptoms were upper airway muscle stiffness and feeding difficulties during neonates. When grow up, most patients have different degrees of recurrent attacks of myotonia and progressed muscle hypertrophy. Some of them have athlete-like special faces but all showed myotonic discharge in eletromyogram.