Schaaf-Yang综合征患儿1例的临床与遗传学分析

Clinical and genetic analysis of a child with Schaaf-Yang syndrome

目的探讨1例Schaaf-Yang综合征(SYS)患儿的临床特征与遗传学病因。方法选取2020年11月30日于华中科技大学同济医学院附属武汉儿童医院就诊的1例SYS患儿为研究对象。抽取患儿及其父母外周静脉血样,应用全外显子组测序对患儿进行基因检测,采用Sanger测序进行家系验证,并对候选变异进行生物信息学分析。结果①本例患儿为男性,1岁9个月,具有发育迟滞、阴茎短小、特殊面容等临床表现。②基因检测结果提示,患儿MAGEL2基因存在c.3078dupG(p.Leu1027Valfs*28)新发杂合变异,Sanger测序结果显示患儿父母均未携带该变异,提示为新发变异。③MAGEL2基因c.3078dupG(p.Leu1027Valfs*28)变异在ESP、1000 Genomes与ExAC等数据库中均未见收载,根据美国医学遗传学与基因组学学会(ACMG)制定的《ACMG遗传变异分类标准与指南》,该变异被评级为致病性变异。结论MAGEL2基因c.3078dupG(p.Leu1027Valfs*28)变异可能为本例SYS患儿的遗传学病因,进一步拓展了MAGEL2基因变异谱。

Objective To explore the clinical characteristics and genetic etiology of a child with Schaaf-Yang syndrome(SYS).Methods Peripheral blood samples of the child and his parents were collected and subjected to whole exome sequencing.Sanger sequencing was used for family constellation verification,and bioinformatic analysis was performed for the candidate variant.Results The child,a 1-year-and-9-month-old boy,had clinical manifestations of retarded growth,small penis,and unusual facies.Genetic testing revealed that the child has harbored a novel heterozygous variant of c.3078dupG(p.Leu1027Valfs*28)of the MAGEL2 gene.Sanger sequencing showed that neither parent of the child carried the same variant.The c.3078dupG(p.Leu1027Valfs*28)variant of the MAGEL2 gene has not been included in the databases of ESP,1000 Genomes and ExAC.According to the Standards and Guidelines for the Interpretation of Sequence Variants of the American College of Medical Genetics and Genomics(ACMG),the variant was judged to be pathogenic.Conclusion The c.3078dupG(p.Leu1027Valfs*28)variant of the MAGEL2 gene probably underlay the SYS in this child,which has further expanded the spectrum of the MAGEL2 gene variants.