• Test Code:
  • Department:
  • Test Synonyms:
    3-MCC deficiencyMCCC1MCCC2
  • CPT Code(s):

3-methylcrotonyl-CoA carboxylase (3-MCC) deficiency is a metabolic disorder involved in the disruption of leucine catabolism. Leucine is used as an energy source when glucose levels are low; defects in either 3-MCC genes (MCCC1 and MCCC2) may not efficiency degrade leucine. This results in potentially dangerous levels of intermediate metabolites of leucine catabolism pathway, specifically 3-hydroxylisovaleric acid or 3-methylcrotonylglycine. The clinical phenotype of this disorder may include feeding difficulties, weakness and poor muscle tone. This condition is inherited in an autosomal recessive manner. This next-generation sequencing test assess the coding region for the two genes associated with 3-MCC deficiency.

Reasons for Referral:

  • Confirmation of a biochemical diagnosis
  • Carrier testing


Next generation sequencing will analyze the exons or coding regions of 2 genes associated with 3-methylcrontyl-CoA carboxylase deficiency using Illumina NextSeq 500 technology and preparing samples using hybridization probes to enrich exonic regions. Promoter, intronic, etc. regions are not assessed on our assay, but may contain variants that impact gene function.

3-methylcrotonyl-CoA carboxylase Deficiency Panel (2 genes):  MCCC1, MCCC2

Specimen Requirements:

Blood:  EDTA or ACD (Solution A or B):

  • Adult: 5 mL
  • Child: 5 mL
  • Infant: 2-3 mL

Saliva: 2 ORAgene Saliva Kit(s) (OGR-500)
Skin Fibroblast: Punch Biopsy, or 2 T-25 confluent flasks
DNA: 1-2µg at a minimum of 50-100ng/µL (DNA must be extracted in a CLIA-certified laboratory or a laboratory meeting equivalent requirements as determined by the CAP and/or CMS)

A REQUISITION FORM MUST ACCOMPANY ALL SAMPLES.  Please include detailed clinical information, including ethnicity, clinical history, and family history.

Test Performed (Days):


Turn Around Time:

8 weeks

Shipment Sensitivity Requirements:

  • Package and ship specimen to remain cold, but not frozen. 
  • Ship via overnight express, using the FedEx priority overnight label provided. 
  • Contact Client Services for shipping kits and instructions at (855) 535-1522.


Additional Info:

The Knight Cancer Institute at Oregon Health & Science University is a pioneer in the field of precision cancer medicine. The institute's director, Brian Druker, M.D., helped prove it was possible to shut down just the cells that enable cancer to grow. This breakthrough has made once-fatal forms of the disease manageable and transformed how cancer is treated. The OHSU Knight Cancer Institute is the only National Cancer Institute-designated Cancer Center between Sacramento and Seattle – an honor earned only by the nation's top cancer centers. It is headquarters for one of the National Cancer Institute's largest research collaboratives, SWOG, in addition to offering the latest treatments and technologies as well as hundreds of research studies and clinical trials.

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