一例Helsmoortel-Van der Aa综合征患儿的临床特征与ADNP基因变异分析

Analysis of clinical features and ADNP variant in a child with Helsmoortel-Van der Aa syndrome

目的分析1例Helsmoortel-Van der Aa综合征(Helsmoortel-Van der Aa syndrome,HVDAS)患儿的临床特征与遗传学特征。方法对患儿及其父母进行基因变异分析,通过文献回顾总结归纳HVDAS患者的临床表型与变异类型。结果患儿表现为特殊面容,伴有自闭症谱系障碍、智力障碍和运动发育迟缓,同时双足第二趾向内卷曲,既往未见报道。基因检测提示其存在ADNP基因杂合变异c.2157C>G(p.Tyr719*),其父母均未见此变异,根据美国医学遗传学与基因组学学会指南评估为致病性变异。文献报道的80例HVDAS患者几乎均存在不同程度的行为异常、智力障碍、语言及运动发育滞后等症状,神经系统、胃肠道系统及眼部频繁受累。ADNP基因的变异类型主要为移码变异与无义变异,热点变异包括p.Tyr719*、p.Asn832Lysfs*81及p.Arg730*等。结论患儿的临床表型与ADNP基因杂合新发变异高度相关,进一步拓展了HVDAS的表型谱。由于HVDAS可导致多个系统受累、表型异质性较大,可结合基因检测技术对其进行确诊。

Objective To analyze the clinical characteristics and genetic etiology of a child with Helsmoortel-Van der Aa syndrome(HVDAS).Methods Genetic testing was carried out for the child and his parents,and the clinical phenotypes and genetic variants of reported cases were summarized through literature review.Results The child has featured peculiar facies,accompanied by autism spectrum disorder,intellectual disability and motor retardation,and curving of the second toes,which was unreported previously.Genetic testing revealed that the child has harbored a heterozygous c.2157C>G(p.Tyr719*)variant of the ADNP gene,which was not found in either parent.Based on the guidelines of the American College of Medical Genetics and Genomics,this variant was rated as pathogenic.Among 80 HVDAS cases described in the literature,most had various degrees of behavioral abnormalities,intellectual disability,language retardation and motor retardation,with common features involving the nervous system,gastrointestinal system and eye.Variants of the ADNP gene mainly included frameshift variants and nonsense variants,with the hotspot variants including p.Tyr719*,p.Asn832lysfs*81 and p.Arg730*.Conclusion The clinical phenotype of the child is closely correlated with the heterozygous variant of the ADNP gene,which expanded the phenotypic spectrum of HVDAS.As HVDAS may involve multiple systems and have high phenotypic heterogeneity,genetic testing technology can facilitate accurately diagnose.