8616 A Novel Mutation of Maturity Onset Diabetes of the Young

Abstract

Abstract Disclosure: K.H. Weerasinghe: None. N. Branis: None. Background: Maturity onset diabetes of the young (MODY) is an autosomal dominant condition characterized by various subsets (Nkonge et al., 2020). A mutation in the glucokinase gene (GCK), otherwise known as MODY type 2, is often characterized by mild hyperglycemia managed with lifestyle modifications (Nkonge et al., 2020). Novel mutations in this gene may differ in their clinical course and need close clinical monitoring. Clinical Case: A 19 year old male presented for evaluation of his diabetes mellitus. In 2020, the patient was hyperglycemic on routine blood work, with asymptomatic features. His condition was managed with lifestyle modifications. The HbA1c was 6.8 and 7; while fructosamine was 338 mmol/L (normal 205-285 mmol/L). Subsequent workup revealed GAD 65 to be less than 5 U/ml(normal range being 0-5 U/ml) with negative islet antibodies. C-peptide was similarly measured and found to be 1.5 ng/ml, within the limits of 1.1-4.4 ng/ml, demonstrating a good pancreatic reserve. A MODY genetic profile was then conducted which revealed a novel mutation in the GCK gene, variant c.1064T>C (p.L355P). As this is a novel mutation, the probability of MODY was calculated, and found to be 75% using the Exeter maturity-onset diabetes of the young (MODY) probability calculator (EMPC).The patient’s clinical course thus far has been managed conservatively as his hyperglycemia has been mild. However, recently the patient’s post prandial sugars were found to be persistently elevated. Pharmacotherapy such as sulfonylureas was discussed however, as per the patient’s wishes, stricter dietary modifications will be applied prior to the initiation of medication. Conclusion: Patients with novel mutations should be closely monitored as the general expected clinical course may vary. These changes are demonstrated in this case report as the patient started developing elevation in postprandial sugar levels uncharacteristically. Close monitoring of the patient’s future clinical status will be essential in learning more about the differences in prognosis and long term management.