Clinical Manifestations, Gene Analysis of Patients with 3-Methylcrotonyl-CoA Carboxylase Deficiency

ABSTRACT

OBJECTIVE: 3-Methylcrotonyl CoA carboxylase deficiency (3MCCD) is classified as organic acid disease due to leucine catabolism. It is among the most common inborn errors of metabolism identified on newborn screening test using tandem mass spectrometry. There is a broad spectrum of clinical presentations. 3-Methylcrotonyl CoA carboxylase converts 3-methylcrotonyl-CoA to 3-methylglutaconyl-CoA using biotin as a coenzyme in mitochondria. Restricting protein diets and supplementing carnitine, glycine, and biotin are known treatments. We reported this study to find out clinical symptoms, type of gene mutation, and effect of treatment. METHODS: This study was based on retrospective data of patients with 3MCCD in Soonchunhyang University Seoul Hospital and Soonchunhyang University Bucheon Hospital between April 2009 to August 2016. RESULTS: All 10 infants were born term infants and had no symptoms. During the neonatal period, abnormalities were detected in the new born screening test using tandem mass spectrometry, 3-hydroxyisovalerylcarnitine was increased. 3-Methylcrotonylglycine (3MCG) and 3-hydroxyisovalreric acid (3HIVA) were examined in urine organic acid assay. The results showed that 3MCG was increased in all 10 children. Except for three of the 10 children, 3HIVA was increased. Genetic tests were performed on all 10 children. MCCC1 gene mutations were detected in four patients and MCCC2 mutations were detected in six patients. After diagnosis, all children were recommended leucine-restricted diets, and seven of the 10 patients started to feed on leucine free formula for the treatment of 3MCCD. CONCLUSION: According to our data, all patients has no symptoms and are shown normal development. There were no clinical symptoms or changes in prognosis according to gene mutation type.