Succinyl-CoA:3-ketoacid CoA Transferase (SCOT) Deficiency: Case Series of Eight Patients with Novel OXCT1 Mutations from a Consanguineous Population in India

Background: Succinyl-CoA:3-ketoacid CoA transferase (SCOT) deficiency is a rare autosomal recessive inborn error of metabolism caused by biallelic mutations in the OXCT1 gene. It results in defective ketone body utilization and presents with recurrent or life-threatening episodes of high anion gap metabolic ketoacidosis. Methods: Analysis of eight patients from seven unrelated families diagnosed with SCOT deficiency based on clinical, biochemical, and molecular findings was performed. Molecular genetic analysis of the OXCT1 gene was carried out in the patients and their parents (trio) using whole-exome sequencing. Results: All eight patients had documented high anion gap ketoacidosis as the primary manifestation. Molecular studies revealed five novel pathogenic variants in OXCT1, with the c.329G>A mutation being the most recurrent among them. One family reported a previously deceased sibling who had succumbed to a similar metabolic crisis. Intensive metabolic management during crises and early recognition improve survival and help prevent long-term complications. Conclusion: This report represents the first series of molecularly confirmed SCOT deficiency cases from South India. The identification of multiple novel mutations expands the mutational spectrum of OXCT1 and underlines the importance of early molecular diagnosis and prompt metabolic intervention in improving patient outcomes.