Diagnosis and treatment of renal glucosuria / 中华实用儿科临床杂志

Renal glycosuria (RG) is an inherited disorder due to defective reabsorption of glucose by the proximal renal tubular.It is attributed to the mutations in the SCL5A2 gene,encoding the sodium-glucose transporter 2 (SGLT2).A defect of SGLT2 is responsible for impaired reabsorption of the filtered glucose in the proximal renal tubular,termed S1,which leads to glycosuria.RG is characterized by normal fasting serum glucose concentration and persistent isolated glucosuria,identification of glucose as the urinary sugar.The inherited pattern of RG is co-dominant inheritance trait with incomplete penetrance.The diagnostic criteria of glycosurias are as follows:a constant and relatively stable urinary glycosurias (10-100 g/d),identification of glucose as the urinary sugar,normal concentration of fasting plasma glucose and normal oral glucose tolerance test,evidence that individuals have normal carbohydrates intake,storage and metabolism.RG does not require special treatment generally,but the advice concerns diet with increasing the intake of carbohydrates.Physical activity should be moderate and professional,and excesive muscle and exercise should be not advisable.

A Case of Isolated Glycosuria Mediated by an SLC5A2 Gene Mutation and Characterized by Postprandial Heavy Glycosuria Without Salt Wasting

Familial renal glycosuria (FRG) is an inherited disorder characterized by persistent glycosuria in the absence of hyperglycemia. It is caused by mutations in the sodium-glucose co-transporter, leading to increase in the renal excretion of glucose and sodium. However, there have been no studies on the role of fasting and postprandial changes in the urinary sodium excretion in patients with FRG. We report a case of renal glycosuria, which was confirmed by a SLC5A2 mutation via gene sequencing, and compared the postprandial urinary glucose and sodium excretion. A 26-year-old man sometimes experienced glycosuria on routine screening; however, other laboratory findings were normal. His fasting and postprandial urinary glucose excretion levels were 295mg/dL and 2,170mg/dL, respectively. The fasting and postprandial urinary sodium excretion levels were 200mEq/L and 89mEq/L, respectively. In patients with FRG, excessive diuresis might be prevented by a compensatory mechanism that reduces postprandial sodium excretion.