Disorders of glucose transport

Abstract

To date, four congenital defects of monosaccharide transport are known (Fig. 11.1). Their clinical picture depends on tissue-specific expression and substrate specificity of the affected transporter. SGLT1 deficiency causes intestinal glucose-galactose malabsorption, a condition that presents with severe osmotic diarrhea and dehydration soon after birth. SGLT2 mutations result in isolated renal glucosuria, a harmless renal transport defect with normal blood glucose concentrations. In GLUT1 deficiency, also termed glucose transporter deficiency syndrome, clinical symptoms, usually microcephaly and an epileptic encephalopathy, are caused by impaired glucose transport at the blood brain barrier and thus into neurons and glia cells. The key finding is a low CSF glucose. Fanconi-Bickel syndrome is the result of a deficiency of GLUT2, an important glucose and galactose carrier within liver, kidney and pancreatic β-cells. Patients typically present with a combination of hepatic glycogen storage and a generalized renal tubular dysfunction which includes severe glucosuria. © 2006 Springer Medizin Verlag Heidelberg.