Genetic and clinical characteristics of Turkish children with Maturity Onset Diabetes of the Young Type 2 (MODY2): A single center experience

Objective: The aim of the study was to investigate the clinical and molecular genetic characteristics of children with maturity-onset diabetes of the youth-glucokinase (MODY-GCK, MODY type 2). Method: Medical files of 21 patients with suspected MODY-GCK were reviewed retrospectively. The file records of the clinical findings, laboratory results and the suspected clinical diagnoses of MODY were based on (1) asymptomatic fasting hyperglycemia (glucose ≥100mg/dl, HbA1c < 7.5% (at least twice measurement) 2) parents with a history of diabetes without complications or mild fasting hyperglycemia (100-144mg/dL). Results: The mean age at diagnosis was 11.5±4.3 years (min-max, 1.9-17.2). The mean (SD) fasting blood glucose level was 119.1 (9.8) mg/dL. The mean (SD) fasting C-peptide level was 1.3 (0.7) ng/mL, the mean (SD) insulin level was 5.9 (2.3) IU/ml, and the mean (SD) HbA1c level at diagnosis was 6.2 (0.5) %. Among 12 variants detected in the GCK gene, 8 were missense mutation, 2 were non-sense mutation, 1 of them was splice site and 1 of them was frameshift mutation. Eight of them (p. Val227Met, p. Ser282Ala, p.Val183Met, p.Met239Thr, p.Arg304Gln, p.Thr229Met, p.Gly163Asp, p.Cys130Ter) have been previously reported in the literature and 4 variants (c.582+4delA, p.Glu436Ter, p.His106ThrfsTer11, p.Asp133Gly) were novel. Conclusion: We found similar phenotype characteristic of children with GCK-MODY among the children with different variants. The most common mutation type was missense and followed by nonsense, splice site and frameshift mutations. Detection of the molecular defect in patients with MODY is vital for the implementation of appropriate treatment approaches.