Abstract: Objective To explore the clinical and genetic characteristics of ALG 1 gene-related congenital disorders of glycosylation (ALG 1 -CDG). Methods The clinical data of 2 children with ALG 1 -CDG were analyzed retrospectively, and the related literatures were reviewed. Results Both were from the same family. The 2 siblings had psychomotor developmental retardation after birth, and suffered from spastic seizures in the early stage, accompanied by microcephaly, hypotonia, inverted nipple, ocular abnormalities, thrombocytopenia and so on. The electroencephalogram showed hypsarrhythmia. Genetic testing indicated that both patients had compound heterozygous variations of c.1129 A>C (p. Met377 Leu) and c. 1263 + 3 A>T in the ALG 1 gene, which were inherited from their parents respectively. Sixty-eight children with ALG 1 -CDG reported in domestic and foreign literature were retrieved, of whom 2 were reported in China. Children with ALG 1 -CDG mainly present with neurological abnormalities such as epilepsy, psychomotor developmental retardation, hypotonia and microcephaly, and other multi-system diseases. Conclusions ALG 1 -CDG can be manifested as infantile spasms. Genetic testing is helpful for diagnosis and genetic counseling. This study extended the ALG 1 phenotype and gene spectrum.

Key words: ALG 1 gene; congenital disorders of glycosylation; infantile spasm; developmental retardation