301-519-2100 • FAX 301-519-2892 • 207 PERRY PARKWAY GAITHERSBURG, MD 20877
SEARCH
3-Methylcrotonyl-CoA Carboxylase (3-MCC) Deficiency
MCCC1 and MCCC2 genes
3-Methylcrotonyl-CoA Carboxylase (3-MCC) deficiency is an autosomal recessive disorder caused by defects in the mitochondrial MCC enzyme which has alpha and beta subunits encoded by the MCCC1 (or MCCA) and MCCC2 (or MCCB) gene respectively. Deficiency of MCCC1 or MCCC2 leads to the same clinical and biochemical phenotype. The phenotype of 3-MCC deficiency is highly variable ranging from severe neurological abnormalities and death in infancy to asymptomatic adults deficiency. This disorder is the most frequent organic aciduria detected in tandem mass spectrometry based newborn screening programs. Often, a child with a positive newborn screen will have follow-up testing consistent with 3-MCC deficiency but never present with symptoms of the disorder. A positive newborn screen in an infant may also lead to the detection of an asymptomatic mother and siblings. A severe presentation of 3-MCC deficiency may include psychomotor retardation, seizures, symptoms of cardiorespiratory failure, and coma while a mild presentation might include fatigue and weakness during catabolic episodes or mild developmental delay. Presentations with cardiomyopathy, brain atrophy and fatty infiltration of liver or muscle may also occur. In patients with biochemically and/or enzymatically confirmed 3-MCC deficiency, 28/28 individuals were found to have two mutations in either the MCCC1 or MCCC2 gene. The method employed by GeneDx is expected to identify >99% of mutations that are detectable by sequencing.
Bi-directional sequence of the coding region and splice junctions of the MCCC1 and/or MCCC2 genes are analyzed. As approximately 64% of 3-MCC patients have mutations in the MCCC2 gene, this gene may be ordered first. Reflex testing (MCCC2>MCCC1) can be performed on request, if two MCCC2 mutations are not identified. Carrier testing and prenatal diagnosis is available once the mutation in the family has been defined.
Information Sheet, including prices and CPT codes
Consent Document
Genetic Test Sample Submission Form (Test Requisition Form) including Payment Options
3-Methylcrotonyl-CoA Carboxylase 1 Deficiency, MCCD Type 1, MCC1 Deficiency, 3-Methylcrotonylglycinuria, Methylcrotonylglycinuria Type I, 3-Methylcrotonyl-CoA Carboxylase 2 Deficiency, MCC2 Deficiency, 3-Methylcrotonylglycinuria II, Methylcrotonylglycinuria Type II, 3-Methylcrotonyl-CoA Carboxylase, alpha; MCCA, biotin, subunit, 3-Methylcrotonyl-CoA Carboxylase, beta, MCCB, non-biotin containing subunit, newborn screening, 3-hydroxyisovalerate, 3-methylcrotonylglycine, 3-hydroxyisovalerylcarnitine, newborn screening, beta-methylcrotonyl-CoA carboxylase deficiency, 3-methyl crotonyl CoA carboxylase deficiency
© 2000 - 2009 GeneDx, Inc. All rights reserved.
