3-Methylcrotonylglycinuria (3MCC) – MCCC1/MCCC2 Sequencing

Disorder 3- Methylcrotonylglycinuria (3MCC)
Gene Name MCCC1/MCCC2
Clinical info 3-Methylcrotonylglycinuria (3MCC) is an autosomal recessive inborn error of leucine metabolism caused by the deficiency of 3-methylcrotonyl-CoA carboxylase. Patients are often identified via newborn screening. Mildly affected or asymptomatic mothers with 3MCC deficiency have also been identified via positive newborn screening in their children. The presentation of this disorder is highly variable with severe cases experiencing significant neurological abnormalities, psychomotor retardation, seizures, cardio-respiratory failure and coma. Ketoacidosis, hypoglycemia and hyperammonemia are often seen. Mild cases may be asymptomatic or display fatigue, muscle weakness and/or mild developmental delay. 3MCC can be caused by a mutation in either the gene coding the alpha subunit (MCCC1) or beta subunit (MCCC2) of the enzyme.
Indications Molecular testing is useful to confirm the diagnosis and to identify the disease causing mutations within a family to allow for carrier testing and prenatal diagnosis.
Associated Tests Organic acids and acylcarnitine profile are available through the Biochemical Diagnostic Lab.
Detection Sequencing of the MCCC1 and MCCC2 genes will detect mutations in 99% of individuals with 3MCC.
Specimen Requirements 5 to 10 ml of peripheral blood collected in an EDTA (lavender top) Vacutainer tube is preferred. The minimal blood needed for reliable DNA isolation is 3 ml
Transport The specimen should be kept at room temperature and delivered via overnight shipping.  FedEx is preferred. If shipment is delayed by one or two days, the specimen should be refrigerated and shipped at room temperature.  Do not freeze the specimen.  Samples collected on Friday can be safely designated for Monday delivery.
Turnaround time 14 days
Prenatal testing Prenatal diagnosis is available if the familial mutations are known. Additional fees for cell culture and maternal cell contamination may apply. Maternal cell contamination studies are required for all prenatal molecular tests. Contact the laboratory prior to sending a prenatal specimen.
CPT Codes Unknown mutation
MCCC1 - 81406
MCCC2 - 81406
Known mutation
MCCC1 - 81404
MCCC2 - 81403
Deletion/Duplication Analysis
81229
Cost $1000 per gene for sequencing

$350 for known familial mutation

$1200 for deletion/duplicaton analysis of both genes or
$700 for deletion/duplication analysis of one gene

Prenatal Known Mutation Testing: $1000
Contact For further information contact Kellie King, MS, Lab Counselor at 1-800-473-9411.

Molecular Diagnostic Lab

The Molecular Diagnostic Lab offers DNA analysis for many genetic disorders via gene sequencing, targeted mutation analysis, MLPA deletion/duplication testing, trinucleotide repeat analysis and next generation sequencing panels.

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