A challenging diagnosis of B-ketothiolase deficiency mimicking type 1 diabetes mellitus

Abstract

Beta-ketothiolase (BKT) deficiency is a disorder of ketone body metabolism and isoleucine catabolism. Patients with BKT deficiency have intermittent ketoacidosis attacks. In this report, we describe an unusual case that mimicked type 1 diabetes presentation. The patient is a 1-year-old boy who presented with clinical and biochemical evidence of diabetes ketoacidosis (DKA). After the resolution of DKA, he was commenced on subcutaneous insulin regimen. Insulin requirements decline over few weeks to 0.3 U/kg/day, and due to normalization of blood glucose coupled with frequent hypoglycemic episodes, insulin was stopped for few months. Later, he developed two additional DKA episodes with intermittent period of no insulin requirement. At 2 years of age, he presented with ketoacidosis and hypoglycemia. The unusual presentation of ketoacidosis accompanied with hypoglycemia prompted genetic testing. Genetic testing revealed a novel homozygous mutation in the ACAT1 gene. The patient was advised to avoid prolonged fasting and started on a low-protein diet. Since then, he had developed mild episodes of ketosis with illness required intravenous hydration. In conclusion, the pediatrician should maintain a high index of clinical suspicion when dealing with children presenting with unusual diabetic ketoacidosis. Delayed diagnosis of BKT, failure of management of acute crisis, and the unnecessary use of insulin can lead to high morbidity and mortality.