Objective To explore the clinical features and genetic mutation characteristics of a case of global developmental delay caused by a novel variant in the CHD1 gene, and to investigate its relationship with Pilarowski- Bjornsson syndrome (PILBOS, OMIM# 617682). Method Trio whole-exome sequencing (trio-WES) was performed to identify the pathogenic gene within the pedigree, and the clinical data of the patient were summarized to analyze both clinical and genetic characteristics. Result The patient was an 8-month-old male and presented to the Department of Pediatric Neurology at our hospital with the main complaint of " developmental delay for more than six months". Trio-WES detection revealed a missense mutation in exon 1 of the CHD1 gene on chromosome 5q15-q21, with a c.13A>G (p.Ser5Gly) mutation (transcript number NM_001270), which represented a novel (de novo) variation consistent with an autosomal dominant inheritance pattern. The final diagnosis was" Comprehensive developmental delay caused by CHD1 gene deficiency". Conclusion There are currently few reports on cases of CHD1 gene mutations, and the identified mutations in this case has not been previously documented. Expanding the genotype phenotype spectrum of CHD1 gene defects also provides data for further understanding of PILBOS disease. Accurate diagnosis relies on molecular genetic testing, and additional cases need to be accumulated for further analysis of genotype phenotype relationships and prognosis evaluation.