Beta-ketothiolase deficiency is a rare autosomal recessive disorder of isoleucine and ketone body metabolism. The disease is characterized by attacks. Ketoacidosis, vomiting and dehydration, lethargy and coma may be seen during attacks. A 15-month-old male was admitted to our hospital with severe acidosis and dehydration. The patient was comatose. Ketoacidosis was suspected because of the odor of acetone on his breath. Blood glucose level was 220 mg/dl and urine ketone was 4+. Branched chain amino acid levels were elevated in his blood sample. Organic acid analysis of urine revealed 2-methylacetoacetyl-CoA thiolase deficiency. Beta-ketothiolase deficiency should be considered in the differential diagnosis of ketoacidosis, although it is a rare metabolic disorder.

Keywords: ketoasidoz, metabolik hastalık, ketoacidosis, metabolic disease