Background: Maturity-Onset Diabetes of the Young (MODY) is a rare monogenic form of diabetes that result in β-cell dysfunction. MODY accounts for 25% of all diabetes cases. We presented here a family with MODY2 caused by a novel heterozygous p.L164I (c.490 C>A) mutation of the GCK gene.
Case: A 15,5-year-old girl was admitted to our department because of fasting hyperglycemia. She had no polyuria, polydipsia and weight loss. Parents had no consanguinity. Her mother was 26 years old with a diagnosis of gestational diabetes in her second pregnancy, used metformin for eight years after having been diagnosed as diabetes. It was learned that her aunt and grandmother had diabetes and her cousin had gestational diabetes. On physical examination body mass index was 23.7 kg/m2 (83p). She did not have acanthosis nigricans. Pubertal assessment revealed Tanner V. Blood glucose level was repeatedly checked and showed fasting hyperglycemia (114 mg/dl) as well as a mildly elevated hemoglobin A1c level 5.56%; and in the analysis of urine glucose and ketone were negative. Autoantibodies of diabetes were negative. A standard oral glucose tolerance test with 75 g of glucose equivalent was performed with a fasting glucose of 103 mg/dl and a 2-h glucose of 153 mg/dl. The fasting insulin concentration was 4.23 μU/ml and 20.88 μU/ml after 2 h. Considering the clinical and family history, mutation analysis of the GCK gene was performed. In the fifth exon of GCK gene of the patients, mother, aunt and cousin, a previously unidentified heterozygous p.L164I (c.490 C>A) mutation was found.
Conclusion: MODY should be suspected in children who is found to have a random rise of blood sugar and has a family history of diabetes. Cases and individuals who have a family history of diabetes should be screened respectively for mutation.
10 - 12 Sep 2016
European Society for Paediatric Endocrinology