Diagnosis and management of glucokinase monogenic diabetes in pregnancy: current perspectives

• Published in: Diabetes, metabolic syndrome and obesity Vol. 12; pp. 1081 - 1089
• Main Author: Rudland, Victoria L
• Format: Journal Article
• Language: English
• Published: New Zealand Dove Medical Press Limited 01-07-2019; Taylor & Francis Ltd; Dove; Dove Medical Press
• Subjects: Analysis; Birth weight; Blood glucose; Care and treatment; Cesarean section; Diabetes; Diabetes mellitus; Diabetes therapy; Fasting; fetal; Fetal development; GCK; Gene mutation; Genes; Genetic aspects; genetics; Gestational diabetes; Glucose; Glucose tolerance test; Hyperglycemia; Hypoglycemia; Insulin; Isoenzymes; Medical diagnosis; MODY; Mutation; Newborn infants; Obesity; Pancreatic beta cells; Phosphates; Phosphorylation; Physiology; Pregnancy; Pregnant women; Review; Technology; Type 2 diabetes; Womens health; Australia; United Kingdom; United Kingdom > UK; mutation; MODY; genetics; fetal; gestational diabetes; GCK
• ISSN: 1178-7007; 1178-7007
• DOI: 10.2147/DMSO.S186610

Glucokinase-maturity-onset diabetes of the young (GCK-MODY) is an autosomal dominant disorder caused by heterozygous inactivating
gene mutations. GCK-MODY is one the most common MODY subtypes, affecting 0.1% of the population and 0.4-1% of women with gestational diabetes mellitus. Glucokinase is predominantly expressed in pancreatic beta cells and catalyzes the phosphorylation of glucose to glucose-6-phosphate. The unique kinetics of glucokinase enable it to change the rate of glucose phosphorylation according to the glucose concentration, thereby regulating insulin secretion. Individuals with GCK-MODY have mildly elevated fasting blood glucose levels (5.5-8.0 mmol/L) and regulate glucose perturbations to a higher set-point, resulting in a relatively flat glucose profile on a 75 g oral glucose tolerance test. The hyperglycemia is usually subclinical and may only be detected on incidental glucose testing. It is important to correctly identify GCK-MODY as the clinical course and management differs substantially from other types of diabetes. Diabetes-related complications are relatively uncommon, so glucose-lowering treatment is not usually required. The exception is pregnancy, where fetal growth and therefore glucose-lowering treatment are predominantly determined by whether or not the fetus inherits the
mutation. The fetal genotype is not usually known but can be inferred from serial fetal ultrasound measurements. If there is evidence of accelerating fetal abdominal circumference on serial ultrasounds, the fetus is assumed to not have the
mutation and treatment of maternal hyperglycemia is indicated to reduce the risk of macrosomia, Caesarean section and neonatal hypoglycemia. If there is no evidence of accelerating fetal growth, the fetus is assumed to have inherited the
mutation and will have a similarly elevated glucose set-point as their mother, so maternal hyperglycemia is not treated. With recent advances in genetic technology, such as next-generation sequencing and noninvasive fetal genotyping, the detection and management of GCK-MODY in pregnancy should continue to improve.