3-Methylcrotonyl Coa Carboxylase Deficiency Type I


3-Methylcrotonyl-Coenzyme A Carboxylase Deficiency Type I(3-MCC Deficiency; MCCD Type I; Methylcrotonylglycinuria Type I; 3-Methylcrotonylglycinuria I) is caused by a defect in the MCCC1 and MCCC2 genes. 3-methylcrotonyl-coenzyme A carboxylase plays an essential role in breaking down proteins from the diet. Specifically, the enzyme is responsible for the fourth step in processing leucine. If a mutation in the MCCC1 or MCCC2 gene reduces or eliminates the activity of 3-methylcrotonyl-CoA carboxylase, the body is unable to process leucine properly. As a result, toxic byproducts of leucine processing build up to harmful levels, damaging the brain and nervous system. Symptoms include recurring episodes of vomiting and diarrhea, lethargy, hypotonia, seizures, and coma.

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References

  1. Baumgartner, MR: Molecular mechanism of dominant expression in 3-methylcrotonyl-CoA carboxylase deficiency. J Inherit Metab Dis. 2005;28(3):301-9. Pubmed
  2. Baumgartner MR, Dantas MF, Suormala T, Almashanu S, Giunta C, Friebel D, Gebhardt B, Fowler B, Hoffmann GF, Baumgartner ER, Valle D. Isolated 3-methylcrotonyl-CoA carboxylase deficiency: evidence for an allele-specific dominant negative effect and responsiveness to biotin therapy. Am J Hum Genet. 2004 Nov;75(5):790-800. Pubmed