Clinical Insights From a Case of Sifrim‐Hitz‐Weiss Syndrome With a <scp> <i>CHD4</i> </scp> Variant: Expanding the Phenotypic Spectrum and Its Response to Growth Hormone Therapy

To enhance clinicians' understanding of Sifrim-Hitz-Weiss syndrome (SIHIWES), this study investigated the clinical phenotypes, genetic characteristics, and response to growth hormone therapy in a patient. A case of a patient with global developmental delay and distinctive facial features is presented. To identify the underlying etiology, peripheral blood samples were collected from the patient and both parents. Whole-exome sequencing (WES) and genomic copy number variation (CNV) analysis were conducted. Candidate variants were confirmed by Sanger sequencing within the family, and bioinformatics tools assessed their pathogenicity. WES identified a de novo heterozygous variant, c.3547C>T (p.Arg1183Cys), in CHD4. Both parents were wild-type at this locus, and CNV analysis revealed no pathogenic variants. Based on ACMG guidelines, this variant is classified as pathogenic. Combining clinical phenotypes with genetic findings, this study confirmed the diagnosis of Sifrim-Hitz-Weiss syndrome. Protein structure modeling indicated that the CHD4 protein harbors an Arg1183Cys variant in the α-helix. The cysteine side chain, containing a sulfur atom, may introduce new chemical interactions, potentially altering CHD4 protein function. Short-term growth-promoting effects were observed with recombinant human growth hormone (rhGH) therapy, providing new insights for managing this disorder. Long-term efficacy and safety should be evaluated in larger studies.