Abstract: Objective　To explore the clinical and genetic characteristics of congenital disorders of glycosylation type Id (CDG-Id). Method　The clinical data and genetic test results of a case of CDG-Id were retrospectively analyzed and related literature were reviewed. Results　A male infant began to have convulsions 2 months after birth, with motor development retardation and low muscle strength and low muscle tension. Brain magnetic resonance imaging showed widened bilateral extracranial space in frontotemporal region and the full bilateral lateral ventricles. Genetic sequencing revealed that there were two heterozygous mutations in the ALG3 gene, C. 494A > G (p. His165Arg) and C. 33del (p. Gly12fs), so the infant was diagnosed of CDG-Id. Conclusions　CDG-Id, a rare type of CDG, is an autosomal recessive inherited disease. The neurological symptoms are the most prominent manifestation. The ALG3 gene detection is helpful for diagnosis.