Glucose-galactose malabsorption is an inherited metabolic disorder characterized by the small intestine's inability to transport and absorb glucose and galactose (simple sugars or monosaccharides). Glucose and galactose have very similar chemical structures, and normally the same transport enzyme provides them with entry into specialized cells in the small intestine where they are absorbed and transferred to other cells. As a result of a mutation on chromosome 22, the transport enzyme does not function properly and the result is glucose-galactose malabsorption.