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Test Code VLCAD SEQ VLCAD Sequencing

Clinical System Name

Very Long Chain Acyl-CoA Dehydrogenase Deficiency Sequencing Request

Description

Very Long Chain Acyl-CoA Dehydrogenase Deficiency (VLCAD) is a treatable disorder of fatty acid metabolism caused by an inability to use very-long-chain fats for energy. It is caused by mutations in the ACADVL gene.

 

 Testing is appropriate for:

  • Infants with abnormal newborn screening results
  • Infants with hypoglycemia, liver disease and cardiomyopathy
  • Children with hypoglycemia, enlarged liver, muscle weakness & cramping with reddish-brown urine

Sample Requirements

Specimen: Whole blood, cord blood

Container(s): Lavender/EDTA, Yellow/ACD A or B

Preferred Vol: 3 mL

Minimum Vol: 1 mL

 

Note: Heparin samples (Green tops) are unacceptable.

 

Specimen: Extracted DNA

Minimum: 10µg

Note: DNA concentration minimum 50 µg/mL; 260/280 ratio 1.70-2.00

  

Specimen: Cultured cells

Acceptable:  Fibroblasts

Container(s): T-25 flasks

Preferred Vol: 2 flasks

 

Processing Instructions

Reject due to: Heparin

Spin: No

Aliquot: No

Temp: Refrigerate

Storage location: Molecular Genetics box in CPA refrigerator #2

 

Off-site collection: Refrigerate blood samples until ready to ship.  Transport all sample types at room temperature via overnight shipping.

Stability

Specimen Type Temperature Time
Cultured cells Room temp 3 days
Whole blood, extracted DNA Room temp 3-5 days
Whole blood, extracted DNA Refrigerated 7 days
Extracted DNA Frozen ok

 

Note: Whole blood samples > 7days may be submitted to be assessed by our lab for acceptability for testing.

Availability

STAT Performed TAT
Contact lab Monday - Friday 2-3 weeks

Follow-up testing requested based on Washington State Lab Newborn Screening Program referrals will be expedited.

Performing Laboratory

Seattle Children's Laboratory

Department

Department:  Molecular Genetics Laboratory

Phone: 206-987-3872

 

Lab Client Services: 206-987-2617

 

Lab Genetic Counselor: LabGC@seattlechildrens.org

Reference Range

Interpretive report will be provided

Methodology

Method: Bi-directional sequencing of the entire coding region (20 exons) of the ACADVL gene.

 

Limitations: Mutations in the promoter region, large deletions, large duplications, or rare recombinant mutations may not be detected by this method.

CPT Codes

81406 (updated 2/2/16 by jconta)

Requisition

Molecular Genetics

Clinical Utility

VLCAD is a treatable disorder of fatty acid metabolism caused by an inability to use very-long-chain fats for energy. Fatty acid metabolism occurs during prolonged fasting and/or periods of increased energy demands (fever, stress) when energy production relies increasingly on fat metabolism. Severe VLCAD can cause hypoketotic hypoglycemia, hepatomegaly, cardiomyopathy and arrhythmias, lethargy, and failure to thrive. The age of onset can be from early infancy to adulthood. Infants can present with hypoglycemia, liver disease, and cardiomyopathy. Children who present outside of the newborn period present with hypoglycemia, enlarged liver, and muscle weakness. Most patients who show symptoms in teen years or adulthood have periods of muscle weakness and cramping with reddish-brown urine. Full gene sequencing will identify greater than 98% of mutations in affected individuals. Carrier testing for biological family members is available once mutations are known.

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