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

Abstract

To analyze the clinical characteristics and genetic etiology of a child with Helsmoortel-Van der Aa syndrome (HVDAS). 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. 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*. 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.