Abstract: Objective To review and summarize the clinical and genetic characteristics of congenital disorders of glycosylation (CDG), and to help its early diagnosis and treatment. Methods To analyze retrospectively clinical characteristics, genotypes, family information, imaging and electrophysiological examinations, laboratory indicators and other related data of eight children with CDG diagnosed in our department in recent years. Results There were four subtypes in eight children with CDG, including five cases of PMM 2 -CDG (two males and three females), one case of ALG 6 -CDG (male), one case of SSR 4 -CDG (male), and one case of SLC 35 A 2 -CDG (male). The average age of onset was 5 . 6 ± 1 . 8 months, the average age of consultation is 18 . 5 ± 4 . 4 months, and the average duration of diagnosis was 10 . 5 ± 5 . 5 months. The nervous system were the most susceptible to be involved in CDG children, presented with moderate to severe developmental delay as the main or initial symptom. Dystonia was presented in all children, and characteristic upper pelvic and (or) buttocks fat pad and nipple depression were common phenotype. There were no characteristic abnormalities in brain imaging. PMM 2 -CDG was the most common CDG subtype, and the cases of ALG 6 -CDG and SSR 4 -CDG were reported for the first time in China. Missense mutation was the main type of CDG mutation. There were 6 sites in the article which have not been reported in the HGMD database. Conclusion CDG is a type of disease involving multiple genes and multiple site mutations. Therefore, the clinical phenotype and genotype are diverse, and early identification and diagnosis are difficult.

Key words: congenital disorders of glycosylation; developmental delay; dystonia; convulsions; fat pad