Background: The detection of hyperglycemia on occasional evaluation raises the diagnosis of diabetes mellitus (DM). Maturity onset diabetes of the young (MODY), namely glucokinase deficiency, should be considered in cases of non-progressive hyperglycemia associated with a positive family history.
Objective and hypotheses: We describe two unrelated cases of asymptomatic hyperglycemia where glucokinase mutations were detected.
Method: Case report.
Results: Case 1: Female child. Family history: the father has impaired fasting glucose and hepatic steatosis; paternal grandparents have type 2 DM. At 3 years of age, hyperglycemia (195 mg/dl) was detected; this evaluation was repeated and fasting glycemias were always high (110128 mg/dl); 3 years later, an OGTT (fasting 122 mg/dl; 120 144 mg/dl) was performed and she was referred to our center. Clinical observation was negative; BMI was 21.6 kg/m2 (75th centile). Laboratory evaluation confirmed the previous results: glycemia 121 mg/dl, A1cHb 6.6%, HOMA 1.3. Anti-GAD antibody was positive (5.4 U/ml) and ICA and IAA autoantibodies were undetectable. The possibility of a glucokinase mutation was considered and a new mutation was detected. Case 2: Male child. Family history: mother had had gestational diabetes and currently has DM treated with gliclazide; maternal grandmother and great-grandfather had type 2 DM. At 3 years of age, during acute gastroenteritis, hyperglycemia (169 mg/dl) was detected. Repeated home monitoring showed both fasting (104117 mg/dl) and postprandial (120160 mg/dl) hyperglycemia. He was referred at 5 years of age; clinical observation was normal. Laboratory evaluation revealed: OGTT glycemia: 109 mg/dl (fasting) and 162 mg/dl (120); A1cHb: 6.3%, HOMA: 0.4; negative autoantibodies. The molecular study confirmed a descrided mutation in the glucokinase gene. In both cases, only dietetic measures have been used so far.
Conclusion: In patients with asymptomatic hyperglycemia, MODY diagnosis should be considered as it has both prognostic and therapeutic implications. The genetic characterization of the subtype is essential.
18 Sep 2014 - 20 Sep 2014