Supplementary Material for: A novel HECW2 variant (c.4354G>A; p. Gly1452Ser) in Chinese patient with developmental delay, neurodevelopmental delay and hypotonia

Abstract
Introduction: Neurodevelopmental disorders (NDDs) due to the HECW2 (MIM:617245), the pathogenic variant is an extremely rare. HECW2-related disorder has been established through the identification of de novo variants in HECW2 gene in patients with NDDs with hypotonia, seizures, and absent language. Case Presentation: This study is the case of the clinical and genetic features of a Chinese girl who presented neurodevelopmental delay, developmental language disorder and hypotonia. Whole exome sequencing revealed a novel likely pathogenic variant in HECW2 (exon26: c.4354G>A; p. Gly1452Ser) in patient, while the variant was absent in her parents with Sanger sequencing. Conclusion: Our objective was to identify the potential site of HECW2, combined with the literature review, to find the correlation between clinical phenotype and genotype.