Background: Fanconi-Bickel syndrome (FBS) is a glycogen storage disease caused by the homozygous mutations of SLC2A2 gene which codes GLUT2 protein. It is characterized by growth retardation, hepatomegaly and hypophosphataemic rickets. While most of the cases with FBS have fasting hypoglycaemia and postprandial hyperglycaemia, only few cases had been shown to have neonatal diabetes (ND).
Case presentation: A 14 days old girl was admitted to hospital with difficulty in feeding. She was born 2620 g from consanguineous parents. She had hyperglycemia (bloodsugar: 651 mg/dl) and metabolic acidosis (blood pH: 7.1 HCO3: 11); intravenous fluid and insulin treatment were started with diagnosis of ND. She had increased parenchymal echogenicity in renal ultrasonography but her renal functional tests (RFT), serum and spot urine electrolytes were normal and she did not have proteinuria. She was discharged with subcutaneus NPH insülin. At the age of four months insülin was discontinued and ramipril was started because of newly diagnosed proteinuria. Molecular genetic study showed her homozygous for a novel missense mutation (p.A127D, c.380C>A) in SLC2A2 gene. Her parents were heterozygous for that mutation. When she was evaluated for FBS findings in addition to present growth failure and proteinuria at nine months of age; RFT and serum electrolytes were normal but tubular phosphate reabsorption was decreased. Unlike increased renal echogenicity compatible with diffuse parenchymal disease, there wasnt liver involvement in abdominal ultrasonography.
Conclusion: ND can be the initial finding of FBS. After excluding frequent causes, FBS should be kept in mind for differential diagnosis for ND. Cases with homozygous SLC2A2 mutations should be followed for growth retardation, hepatomegaly and hypophosphataemic rickets.
01 Oct 2015 - 03 Oct 2015