A 10 year old caucasian boy is referred for further management after his fasting plasma glucose is found to be 132 mg/dl. During the preceding year, he had experienced several episodes of increased urination, thirst and appetite. His mother and maternal grandfather were diagnosed with diabetes at the ages of 27 and 30 respectively.
Low dose dexamethasone suppression test: negative Free-T3, Free-T4, S. TSH: Within normal parameters
No autoantibodies (ICA, IAA or GAD) are detected.
The C-peptide level is 1.50 ng/ml (normal: 0.51 - 2.72)
A heterozygous missense mutation is detected in the glucokinase gene