ESPE Abstracts

Neonatal Diabetes mellitus (NDM) is a rare genetic disease. In this report, we presented a case of NDM due to mutation in GCK gene. A male baby born to a non-consanguineous parent at 42 weeks of gestation with a birth weight of 3.2 kg. The mother was diagnosed with gestational diabetes; no special treatment was given. The first episode of hyperglycemia was registered at the age of 13 days at hospitalization due to bronchitis /blood glucose -6.2⁓7.9 mmol/l. Due to mild hyperglycemia no treatment was given. A regular monitoring of glycemia until 6 months of age, with values ranging from 5.0-6.2 mmol/l FBG and 5.2-9.7 mmol/l PBG, HbA1c 6.2 %. At 3 months of age, he became ill with COVID-19 and was hospitalized. Episodes of mild hyperglycemia were also recorded during that period. At this time, the child was referred to a hospital for diagnosis and choice of treatment tactics. During hospitalization, clinical and laboratory tests were performed, as well as glycemic monitoring, in which the increase in FBG did not exceed the values of 6.2 mmol/l, and PBG 8.2 mmol/l, C peptide with normal range. There was no special treatment given to the child. Sanger sequencing of GCK was performed, which revealed a heterozygous GCK nonsense mutation (c.1183G>T (p.E395*)), which was also present in her mother. Heterozygous inactivating mutations in the gene encoding the glucose sensing enzyme glucokinase are not rare and result in partial glucokinase deficiency. This causes mild hyperglycemia often diagnosed incidentally in adulthood as maturity-onset diabetes of the young (MODY). The degree of hyperglycemia is uniform irrespective of mutation type, and treatment of hyperglycemia is not required, as it does not result in the micro- or macrovascular complications seen with type 1 and type 2 diabetes. In this case GCK-MODY diagnosed in cases referred for genetic testing for suspected NDM, we have shown that neonatal hyperglycemia is an incidental finding, does not require treatment and follows a benign course in childhood and the same time this report contains the first description on GCK mutations in Armenian patients with non-consanguineous parents.