Comparison of Ketogenesis and Ketolysis Defects: A Retrospective Single-Center Study of 30 Patients

Objective: Despite overlapping features, these 2 groups of disorders may exhibit distinct clinical and biochemical profiles. This study aimed to evaluate and compare the clinical presentation, laboratory findings, neuroimaging characteristics, genotypic spectrum, and clinical outcomes of patients with ketogenesis and ketolysis defects. Materials and Methods: Thirty patients diagnosed between 1986 and 2023 were retrospectively reviewed. Diagnosis was confirmed by clinical findings, biochemical, and genetic/enzymatic testing. Data included demographic details, clinical manifestations, neurodevelopmental status, laboratory results, imaging findings, genetic information, and treatments. Results: Of the 30 patients, 13 (43.3%) were diagnosed with 3-hydroxy-3-methylglutaryl-CoA lyase deficiency (HMGCLD), 14 (46.7%) with 2-methylacetoacetyl-coenzyme A thiolase deficiency (MATD), and 3 (10%) with succinyl-CoA:3-ketoacid CoA transferase deficiency (SCOTD). Patients with ketolysis defects presented at a later median age (210 vs. 30 days, P < .009) and exhibited more profound metabolic acidosis (pH 7.06 ± 0.18 vs. 7.26 ± 0.12, P = .028). Common presenting symptoms included vomiting in 25 (83.3%), hypoglycemia in 9 (33.3%), and seizures in 5 (16.6%). Leigh-like neuroimaging findings were observed in 3 HMGCLD patients. Biallelic pathogenic variants in HMGCL, ACAT1, or OXCT1 were identified in 14 patients. Dialysis was required in 1 MATD and 1 SCOTD case. Excluding those lost to follow-up, the mortality rates among the remaining 18 patients were 1/8, 12.5% in 2/9 HMGCLD, and 22.2% in MATD. One of the patients with SCOTD was alive at the time of the last follow-up. Conclusion: Patients with ketolysis defects are more likely to present later and with severe metabolic acidosis, occasionally requiring renal replacement therapy. Delayed diagnosis may hinder timely intervention, potentially contributing to increased mortality.