Glucose-galactose malabsorption is a condition in which the body cannot take in (absorb) the sugars glucose and galactose, which primarily results in severe diarrhea. Beginning in infancy, severe diarrhea results in weight loss and dehydration that can be life-threatening. Small amounts of the simple sugar glucose in the urine (mild glucosuria) may occur in this disorder. Rarely, affected infants develop kidney stones due to deposits of calcium in the kidneys (nephrocalcinosis).

Mutations in the SLC5A1 gene cause glucose-galactose malabsorption. The SLC5A1 gene provides instructions for producing a protein called sodium/glucose cotransporter protein 1 (SGLT1). This protein is found mainly in the intestinal tract and the kidneys. It spans the membrane of cells in these body systems and moves (transports) glucose and galactose from outside the cell to inside the cell. Sodium and water are transported across the cell membrane along with the sugars in this process. Glucose and galactose are simple sugars; they are present in many foods, or they can be obtained from the breakdown of lactose or other sugars and carbohydrates in the diet during digestion.

Glucose-galactose malabsorption is a rare disorder; only a few hundred cases have been identified worldwide. However, as many as 10 percent of the population may have a somewhat reduced capacity for glucose absorption without associated health problems.

This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.

Published Date: April 01, 2020
Published By: National Institutes of Health