Aminoaciduria and Glycosuria in Children

Clinical features of pediatric renal glucosuria cases due to SLC5A2 gene variants

“…Glucose reabsorption in the proximal convoluted tubule is an active carrier-mediated process mediated via specific transporters. 1 In the apical tubular epithelial membrane, there is a sodium solute symporter called SGLT1 which is encoded by the SLC5A1 gene and defined as a high-affinity, low-capacity glucose transporter. This transporter is also located in the intestinal membranes, so mutations related to SLC5A1 result in glucose-galactose malabsorption, which can manifest as severe diarrhea and dehydration and mild glycosuria.…”

“…Once glucose is internalized into the tubular epithelial cytoplasm, the increased intracellular glucose concentration forces the glucose to leave the cell along its concentration gradient via facilitative glucose transporters located in the basolateral side of the membrane. These transporters are known as the glucose transporter (GLUT) family, and mutations related to GLUT2 located on the basolateral side of the renal tubular epithelium result in Fanconi syndrome 1,16 …”

“…In normal circumstances, there are small amounts of glucose in the final urine. Glucose reabsorption in the proximal convoluted tubule is an active carrier‐mediated process mediated via specific transporters 1 …”

“…In normal renal tubular functions, most of the glucose filtered from the glomeruli is reabsorbed from the early proximal tubules, leaving only negligible amounts of glucose in the final urine. 1 Glycosuria appears either as a sign of generalized proximal tubular dysfunction or in cases where either the reabsorption threshold has been exceeded or the minimal glucose threshold is reduced, as in the case of familial renal glycosuria (FRG). 2 Familial renal glycosuria is a rare renal tubular disorder characterized by a variable loss of glucose in the urine despite normal blood glucose levels, which is seen in a condition in which other tubular functions are preserved.…”

“…The kidneys play a critical role in the proper maintenance of glucose homeostasis. In normal renal tubular functions, most of the glucose filtered from the glomeruli is reabsorbed from the early proximal tubules, leaving only negligible amounts of glucose in the final urine 1 . Glycosuria appears either as a sign of generalized proximal tubular dysfunction or in cases where either the reabsorption threshold has been exceeded or the minimal glucose threshold is reduced, as in the case of familial renal glycosuria (FRG) 2 …”