PSUN249 Starvation Ketoacidosis as the Presenting Finding of Glycogen Storage Disorder Type III

: A 30-year woman with a history of heart transplantation and a history of post-transplant diabetes mellitus presents with severe euglycemic ketoacidosis. Initial concern was for diabetes related ketoacidosis given history of diabetes however blood glucose was within goal range in the absence of pregnancy and use of sodium glucose transporter type 2 inhibitor use. Initial laboratory evaluation showed a serum glucose of 177 mg/dL, a serum beta hydroxybutyrate of greater than 12.66 mmol/L, serum lactate of 0.6 mmol/L, with a calculated anion gap of greater than 30 mmol/L. C-peptide levels were repeatedly normal and appropriate for blood glucose level ranging between 2.8 ng/mL and 7.5 ng/mL ruling out insulin deficiency as causative. It was discovered that the patient had intentionally fasted for greater than 18 hours and thus had not used the premixed insulin regimen prescribed. Metabolic disturbance corrected with a dextrose and insulin infusion. Evaluation for inborn error of metabolism showed: acylcarnitine panel returned normal making an inborn error of fatty acid metabolism unlikely. The mitochondrial DNA mutation panel was negative for point mutations or deletions. Further testing for urinary organic acids did not reveal elevation of 3-hydroxybutyric acid suggesting SCOT enzyme levels were sufficient in our patient. Review of pathology records for heart transplantation completed for idiopathic cardiomyopathy 20 years prior to this presentation showed high levels of glycogen deposition prompting evaluation for glycogen storage disorders. Results revealed a heterozygous abnormality at exon 9 of the AGL gene; AGL gene c.1139A>G (p.Glu380Gly). This is not a reported pathologic mutation, and given the heterozygosity of the mutation in this autosomal recessive condition, it is felt that either environmental factors or the presence of other unrecognized genetic mutations allowed for the phenotypic expression of GSDIII with euglycemic starvation ketoacidosis. The patient was treated with dietary counseling regarding ketone suppression with basal insulin during periods of fasting and preference to avoid periods of prolonged fasting with frequent carbohydrate-containing meals. CONCLUSION: This case represents a novel, potentially pathologic defect in the AGL gene. This finding should prompt further investigations into genetic variabilities that may lead to this phenotypic expression. Presentation: Sunday, June 12, 2022 12:30 p.m. - 2:30 p.m.