Abstract: 　Objective　To analyze the clinical features and SLC5A1 gene mutation of congenital glucose-galactose malabsorption (CGGM) in a child. Method　The clinical data of a child with CGGM diagnosed and treated in November 2016 were collected. The mutation of SLC5A1 gene was detected by exome sequencing of single gene disease (family). Results　The boy began to have diarrhea on the third day after birth, stools being yellow watery, having fever but no chills. Multiple electrolyte tests showed a significant increase in blood sodium with the highest value at 162 mmol/L. Two variants of SLC5A1 gene, c.406 (exon 5) delT and c.92T>A (exon 1), were found to be highly correlated with glucose-galactose malabsorption disorder (OMIM: 606824) by whole-gene exon examination. Parents of the boy had normal phenotype and his mother had heterozygous C. 92T > A. The results of glucose and fructose provocation tests suggested that the boy had sugar malabsorption and the diagnosis of glucose-galactose malabsorption was confirmed. Therefore, the children were fed with carbohydrate free liquid milk and fructose. In half a day, the child's stool turns into solid. And the child was discharged at the age of 10 months and the condition of the patient was good at follow-up. Conclusion　CGGM is a rare autosomal recessive hereditary disease. Persistent watery diarrhea occurs soon after birth. Gene analysis can confirm the diagnosis. Early diagnosis and carbohydrate free liquid milk and fructose feeding are important for prognosis.

Key words: 　congenital glucose-galactose malabsorption;　SLC5A1 gene;　diarrhea