Hyperglycemia and hypoinsulinemia in patients with Fanconi-Bickel syndrome.
Fanconi-Bickel syndrome (FBS) is a rare autosomal recessive disorder characterized by the combination of hepatorenal glycogen accumulation and Fanconi-type nephropathy. Mutations in GLUT2, the gene for facilitative glucose transporter protein 2 (GLUT2), cause FBS.


OBJECTIVE
To evaluate glucose and insulin responses to oral glucose load in patients with FBS.


METHODS
Ten children (7.3 +/- 4.8 years) diagnosed with FBS in early infancy underwent a standard oral glucose tolerance test (OGTT); plasma glucose (PG) and serum insulin concentrations were measured at 30-min intervals for 2 hours. HbA1c, insulin-like growth factor-I, and fasting lipid profiles were also measured.


RESULTS
Mean fasting and 2-h PG concentrations were 3.8 +/- 0.9 mmol/l and 8.6 +/- 3.0 mmol/1, respectively. 2-hour PG levels were above 11.1 mmol/l in two patients (20%) and between 7.75 and 11.1 mmol/ in four patients (40%). HbA1c was normal in all the patients with a mean of 5.4 +/- 0.3%. Mean fasting and peak serum insulin levels were 8.7 +/- 0.8 pmol/ and 98.6 +/- 43.0 pmol/l, respectively, and did not differ between the patients with normal and abnormal OGTT. Patients with abnormal OGTT were younger (4.8 +/- 3.2 vs 11.0 +/- 4.8 yr; p = 0.04). Fasting PG increased with age (r = 0.80, p < 0.01). Total and LDL cholesterol as well as triglyceride concentrations were elevated.


CONCLUSIONS
Most but not all patients with FBS have impaired glucose tolerance/diabetes range hyperglycemia after OGTT while maintaining normal HbA1c. Patients with FBS are relatively hypoinsulinemic. Both fasting hypoglycemia and post-OGTT hyperglycemia seem to improve with age.
Taha
Doris
D
Division of Pediatric Endocrinology, Department of Pediatrics, King Faisal Specialist Hospital & Research Centre, Jeddah, Saudi Arabia. dtaha@kfshrc.edu.sa
Al-Harbi
Naffaa
N
Al-Sabban
Essam
E
D000293:Adolescent; D001786:Blood Glucose / Q000032:analysis; D002648:Child; D002675:Child, Preschool; D005198:Fanconi Syndrome / Q000097:blood / Q000150:complications*; D005260:Female; D030342:Genetic Diseases, Inborn / Q000097:blood / Q000150:complications; D005951:Glucose Tolerance Test; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D006943:Hyperglycemia / Q000150:complications*; D007003:Hypoglycemia / Q000097:blood; D007223:Infant; D007328:Insulin / Q000097:blood*; D008107:Liver Diseases / Q000097:blood / Q000150:complications* / Q000151:congenital; D008297:Male
D001786:Blood Glucose; D006442:Glycated Hemoglobin; D007328:Insulin; C517652:hemoglobin A1c protein, human