Maturity-Onset Diabetes of the Young (MODY) is a rare monogenic form of diabetes that result in β-cell dysfunction. The most common types of MODY are due to mutations in the glucokinase (MODY2) and hepatocyte nuclear factor1-α (MODY3). Heterozygous mutations in the gene encoding glucokinase result in MODY2, which causes mild fasting hyperglicemia (100-144 mg/dl) already at birth. In this article, we report a 4-years-old male who has fasting hyperglycemia that was detected by the family history of diabetes and diagnosed with MODY2 by determinating the heterozygous Ala53Val mutation in GCK gene.

Keywords: Fasting hyperglycemia, monogenic diabetes, glucokinase