Test Code | D5021 |
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Test Summary |
This test analyzes the CYP21A2 gene for deletions and duplications by MLPA. |
Turn Around Time | 2 weeks |
Acceptable Sample Types | DNA, Isolated , Dried Blood Spots , Saliva , Whole Blood (EDTA) |
Acceptable Billing Types | Institutional Billing , Self (patient) Payment |
NY Approved | No |
CPT Codes** | 81479(x1) |
Multiplex Ligation-Dependent Probe Amplification (MLPA) enables the detection of deletion and duplications of single and multiple exons within a given gene (PMID: 20938835). It is a semi-quantitative technique to determine relative copy number using a multiplex PCR-based reaction. Only hybridized and ligated adjacent probe oligonucleotides are amplified by PCR, and thus are specific for the sequence of interest. This test involves copy number analysis of CYP21A2 gene. Reciprocal exchanges between CYP21A2 and its pseudogene will be missed in this test. This assay should be used in conjunction with sequence analysis.
Congenital adrenal hyperplasia (CAH) is an autosomal recessive disorder which results from a deficiency in one of the enzymes involved in cortisol biosynthesis. CAH affects about 1 in 5,000 births, with a carrier frequency of 1 in 35. In about 95% of cases, CAH is caused by deficiency of the steroid 21-hydroxylating enzyme encoded by the CYP21A2 gene. The inactive pseudogene CYP21A1P is located at a very close distance from CYP21A2. Both genes have 10 exons and are about 3.4 kb long. The great majority of the CYP21A2 mutant alleles arise through recombination between CYP21A2 and CYP21A1P. Approximately 20% of mutant alleles have DNA deletions of 30 kb that have been generated by unequal meiotic crossing-over, whereas 75% are due to gene conversion events, where an inactivating mutation is present in the CYP21A2 gene that is usually only present in the CYP21A1P pseudogene.
This is a MLPA based assay for the detection of large deletions/duplications and some frequent point mutations in the CYP21A2 gene. The MRC-Holland reagent kits and the Applied Biosystem 3730xl DNA Analyzer instrument are used to generate fragment analysis data.
Collection | Required DNA Quantity by Test Type*:
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Sample Condition | * Required DNA Quality: High molecular weight DNA (>12kb). A260/A280 reading should be ≥ 1.8. A260/230 a ratio range of 1.8 to 2.2. Contact the laboratory for specific amounts if total ng cannot be met. |
Shipping | Ship overnight at ambient temperature. |
Special Sample Instructions |
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Collection Container(s) | EDTA (purple top) |
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Collection | Infants (< 2-years): 2 to 3 mL; Children (>2-years): 3 to 5 mL; Older children and adults: Minimum 5mL. The blood tube should be inverted several times immediately after blood collection to prevent coagulation. |
Sample Condition | Store at ambient temperature. Do not refrigerate or freeze. |
Shipping | Ship overnight at ambient temperature ensuring receipt within 5-days of collection. |
Special Sample Instructions | Clotted or hemolyzed samples are not accepted. |
Collection Container(s) | Oragene™ Saliva Collection Kit or ORAcollect-Dx kit |
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Collection | Collect saliva on an Oragene™ Saliva Collection Kit ORAcollect-Dx kit according to the manufacturer's instructions. |
Sample Condition | Store at ambient temperature. Do not refrigerate or freeze. |
Shipping | Ship overnight at ambient temperature. |
Special Sample Instructions | Please contact Revvity Omics to request the saliva collection kit for patients who cannot provide a blood sample as whole blood is the preferred sample. Testing using Saliva swabs is currently not available for customers in India. Contact the Revvity Omics laboratory for more information. |
Collection Container(s) | Dried blood spot card |
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Collection | Follow kit instructions. Briefly, allow blood to saturate the card until indicated areas are filled and blood has soaked through the card. Air dry the card at ambient temperature for at least 3 hours.
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Sample Condition | Follow the instructions provided with the collection set. Store the dried blood at ambient temperature for up to two days. If the specimen cannot be sent as soon as it is dry, the filter paper should be placed in a sealable plastic bag and stored in a refrigerator (≤ 8°C) or preferably in a freezer. |
Shipping | Follow kit instructions. Double bag and ship overnight at ambient temperature. |