Genetic analysis was performed on a family of fraternal twins affected with Dravet syndrome by genetic tests whose parents were normal. To further analyze the cause of the disease, the fraternal twins were subjected to whole exome sequencing (WES), and the family was verified by Sanger sequencing, with the father semen and peripheral blood DNA were further analysed by target sequencing. The WES test identified a heterozygous c.5348C>T (p.Ala1783Val) variant of the SCN1A gene in the fraternal twins, which was predicted to be pathogenic and was detected in the father peripheral blood and semen, but not in the mother. So the mosaicism mutation of paternal SCN1A gene might be the genetic cause of Dravet syndrome in offspring.
对1例亲代表型正常但生育Dravet综合征患儿的家系进行遗传学分析，通过对一个家庭中表型相似的两个患儿进行全外显子组测序（WES），对患儿及患儿父母进行Sanger测序验证，对患儿父亲精液和外周血DNA突变位点做靶向测序进一步分析，探讨患儿的发病原因。通过WES检测发现患儿SCN1A基因c.5348C>T（p.Ala1783Val）杂合变异，为致病性变异，患儿父亲外周血及精液检查该位点发生嵌合变异，患儿母亲无该位点变异，进而推测父源SCN1A基因嵌合变异是导致子代Dravet综合征发生的遗传学病因。.