Objective:To explore the clinical manifestations and genetic characteristics of Wolf-Hirschhorn syndrome (WHS) to improve the ability of diagnosis and differential diagnosis of the disease.Methods:The clinical features and auxiliary examinations and treatment of a proband with WHS caused by microdeletion of 4p16.3 segment who admitted to the Third Affiliated Hospital of Zhengzhou University in December 2021 were recorded, and whole exome sequencing (WES) of the family was performed. The prognosis was followed up.Results:The female proband, 11 months old, presented with convulsions at the age of 8 months, with the characteristics of heat sensitivity and cluster seizures, and her identical twin sister had a similar medical history. Physical examination found malnutrition, retarded development, special face, prominent forehead, wide nasal bridge, small jaw, precordial murmur and grade 3/6 murmur in the whole period, hyperactivity of P2, and low limb muscle tone. The whole exon and copy number variation (CNV) test of the family revealed that the proband had a 1.99 Mb heterozygous deletion in the chromosome 4p16.3 segment, including WHSC1 (NSD2), WHSC2 (NEFLA) and other genes. Copy number variation sequencing (CNV-Seq) of the proband and her sister showed 1.97 and 1.92 Mb heterozygous deletion of chromosome 4p16.3, respectively. Genealogical analysis by quantitative polymerase chain reaction revealed that the CNV was de novo, and it was determined to be a pathogenic variant according to the American College of Medical Genetics and Genomics guidelines. The proband took sodium valproate orally, and her sister took oral sodium valproate, zonisamide, and levetiracetam successively, and at the same time they received family rehabilitation training. The age at the last follow-up was 1 year and 8 months. Neither of them had convulsions again in the past 3 months, but the developmental delay was obvious. Conclusion:WHS patients may present with growth retardation, epilepsy, Greek warrior helmet-like special face, and congenital heart disease, and may have microdeletions in the chromosome 4p16.3 segment.