SUN-552 - Ketosis-Prone Diabetes Phenotype in A Young Woman: A Diagnostic Challenge Beyond Classic Demographics

Background:
Ketosis-prone diabetes (KPD), also known as Flatbush diabetes, is characterized by presentation with diabetic ketoacidosis (DKA) in patients who lack autoimmune markers of type 1 diabetes and demonstrate preserved β-cell function. While KPD presents predominantly in middle-aged, overweight African American males, we present a case of KPD in a young African American female.


Case Presentation:
A 19-year-old African American female (BMI 25.46) with a reported history of insulin-dependent T2DM (diagnosed at age 12) but non-adherent to therapy, presented to the ED after being found unresponsive. She was found to be in DKA (glucose 683 mg/dL, HbA1c > 14%, anion gap >23, pH < 7, HCO3 14.6, Beta Hydroxybutarate 9.1) and to have Klebsiella pneumoniae meningitis. Autoimmune diabetes markers, including GAD65, IA-2, and ZnT8 antibodies, were negative; a C-peptide level obtained during a DKA admission one month earlier was normal (1.4 ng/mL). She was managed with antibiotics and insulin infusion followed by basal–bolus insulin therapy and was discharged home on a basal insulin regimen.


Discussion:
Ketosis-prone diabetes is defined as diabetes presenting with diabetic ketoacidosis or unprovoked ketosis in the absence of islet autoimmunity and with preserved or recoverable β-cell function evident by normal C-peptide level. Pathogenesis is unclear; since β-cell dysfunction is transient, prospective cohort data suggests that a substantial proportion of individuals with an A⁻β⁺ ketosis-prone phenotype can discontinue insulin and remain insulin-independent at 12 months following an initial DKA presentation, with one study reporting ~68% insulin independence in this subgroup at one year. Although a formal diagnosis of ketosis-prone diabetes was not assigned during hospitalization, the patient’s clinical and biochemical features (DKA, negative autoantibodies, markedly elevated HbA1C, preserved C-peptide) are most consistent with an A⁻β⁺ ketosis-prone diabetes phenotype. In the cohort described by Balasubramanyam et al., the mean age at diagnosis was 34.0 ± 14.6 years, mean BMI was 27.2 kg/m with 67–75% of cases occurring in men. Our patient’s presentation at age 19 corresponds to a z score of –1.03, placing it around the 15th percentile. Therefore, diagnosis in early adulthood and female sex places our patient outside of the typical demographic profile described for KPD and represents a distinct presentation of this phenotype.


Conclusion:
Ketosis-prone diabetes should be considered in patients presenting with DKA when autoimmune markers are negative and β-cell function is preserved, regardless of their age and gender. Timely KPD diagnosis can accurately guide treatment and may prevent unnecessary insulin therapy duration.

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