Pyruvate carboxylase deficiency type C as a differential diagnosis of diabetic ketoacidosis

Objectives: Type C pyruvate carboxylase (PC) deficiency is extremely rare, and has been described in only a few patients in literature to date. Herein, we present the case of a four-year-old patient admitted with diabetic ketoacidosis and diagnosed with type C PC deficiency based on clinical and biochemical findings.

Case presentation: A Turkish girl was referred to the intensive care unit at the age of three-years with a three-day history of vomiting and abdominal pain. Upon physical examination, the patient was found to be experiencing lethargy, dehydration, and Kussmaul breathing. Hyperglycemia, metabolic acidosis, and ketonemia were detected. Clinical and laboratory findings pointed to a prediagnosis of diabetic ketoacidosis. Intravenous fluid, bicarbonate, and insulin treatments were initiated. Elevated alanine and proline levels were recorded in plasma amino acid analysis, while urinary organic acid level analysis revealed increased lactate, pyruvate, 3-OH-butyrate, and acetoacetate levels. Whole exome sequencing revealed homozygous c.584C>T (p.Ala195Val) mutation in the PC gene.

Conclusions: To date, there have been no reports in literature of type C phenotype patients manifesting with DKA. Our case is the first case with the type C phenotype to be admitted with clinical and laboratory findings of DKA.