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HelpTest ID CYPZ 21-Hydroxylase Gene (CYP21A2), Full Gene Analysis
Useful For
May be used to identify CYP21A2 mutations in individuals with a suspected diagnosis of 21-hydroxylase deficient CAH when a common mutation panel is negative or only identifies 1 mutation.
In prenatal cases of ambiguous genitalia detected by ultrasound, particularly when the fetus is confirmed XX female by chromosome analysis.
This test ID should also be used for known/familial variant analysis for CYP21A2. Due to the complexity of the CYP21A2 locus, site specific testing for known/familial variants is not offered for this gene.
Genetics Test Information
This test includes Sanger gene sequencing and multiplex ligation-dependent probe amplification to evaluate the CYP21A2 gene for carrier screening and diagnosis of 21-hydroxylase deficient congenital adrenal hyperplasia (CAH).
Highlights
This test aids in carrier screening and diagnosis of 21-hydroxylase deficient congenital adrenal hyperplasia (CAH).
Full gene sequencing and multiplex ligation-dependent probe amplification are used to detect the common pathogenic CYP21A2 variants, CYP21A2 full gene deletions, and rare CYP21A2 variants.
Reflex Tests
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| MATCC | Maternal Cell Contamination, B | Yes | No |
| CULFB | Fibroblast Culture for Genetic Test | Yes | No |
| CULAF | Amniotic Fluid Culture/Genetic Test | Yes | No |
Testing Algorithm
For prenatal specimens only: If amniotic fluid (nonconfluent cultured cells) is received, amniotic fluid culture will be added and charged separately. If chorionic villus specimen (nonconfluent cultured cells) is received, fibroblast culture will be added and charged separately. For any prenatal specimen that is received, maternal cell contamination studies will be added.
Special Instructions
Method Name
Polymerase Chain Reaction (PCR) Amplification Followed by DNA Sequence Analysis and Gene Dosage Analysis by Multiplex Ligation-Dependent Probe Amplification (MLPA)
Reporting Name
CYP21A2 Gene, Full Gene AnalysisSpecimen Type
VariesAdvisory Information
This test is a molecular analysis of the CYP21A2 gene and does not include biochemical analysis of steroids. For biochemical analysis for congenital adrenal hyperplasia (CAH) which includes cortisol, androstenedione and 17-Hydroxyprogesterone, see CAH21 / Congenital Adrenal Hyperplasia (CAH) Profile for 21-Hydroxylase Deficiency.
Additional Testing Requirements
All prenatal specimens must be accompanied by a maternal blood specimen; order MATCC / Maternal Cell Contamination, Molecular Analysis on the maternal specimen.
Shipping Instructions
Specimen preferred to arrive within 96 hours of collection.
Prenatal specimens can be sent Monday through Thursday and must be received by 5 p.m. CST on Friday in order to be processed appropriately.
Specimen Required
Specimen Type: Whole Blood
Container/Tube:
Preferred: Lavender top (EDTA)
Specimen Volume: 3 mL
Collection Instructions:
1. Invert several times to mix blood.
2. Send specimen in original tube.
Prenatal Specimens
Specimen Type: Amniotic fluid
Container/Tube: Amniotic fluid container
Specimen Volume: 20 mL
Specimen Stability Information: Refrigerated (preferred)/Ambient
Specimen Type: Chorionic villi
Container/Tube: 15-mL tube containing 15 mL of transport media
Specimen Volume: 20 mg
Specimen Stability Information: Refrigerated
Acceptable
Specimen Type: Confluent cultured cells
Container/Tube: T-25 flask
Specimen Volume: 2 flasks
Collection Instructions: Submit confluent cultured cells from another laboratory.
Specimen Stability Information: Ambient (preferred)/Refrigerated
Specimen Minimum Volume
Amniotic Fluid: 10 mL
Blood: 1 mL
Chorionic Villi: 5 mg
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Varies | Ambient (preferred) | |
| Frozen | ||
| Refrigerated | ||
Reference Values
An interpretive report will be provided.
Day(s) and Time(s) Performed
Performed weekly; Varies
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.CPT Code Information
81405-CYP21A2 (cytochrome P450, family 21, subfamily A, polypeptide2) (eg, steroid 21-hydroxylase isoform, congenital adrenal hyperplasia), full gene sequence
81402-CYP21A2 (cytochrome P450, family 21, subfamily A, polypeptide2) (eg, congenital adrenal hyperplasia, 21-hydroxylase deficiency), common variants (eg, IVS2-13G, P30L, I172N, exon 6 mutation cluster [I235N, V236E, M238K], V281L, L307FfsX6, Q318X, R356W, P453S, G110VfsX21, 30-kb deletion variant)
Fibroblast Culture for Genetic Test
88233-Tissue culture, skin or solid tissue biopsy (if appropriate)
88240-Cryopreservation (if appropriate)
Amniotic Fluid Culture/Genetic Test
88235-Tissue culture for amniotic fluid (if appropriate)
88240-Cryopreservation (if appropriate)
Maternal Cell Contamination, B
81265-Comparative analysis using Short Tandem Repeat (STR) markers; patient and comparative specimen (eg, pre-transplant recipient and donor germline testing, post-transplant non-hematopoietic recipient germline [eg, buccal swab or other germline tissue sample] and donor testing, twin zygosity testing or maternal cell contamination of fetal cells (if appropriate)
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| CYPZ | CYP21A2 Gene, Full Gene Analysis | In Process |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 37488 | Result Summary | 50397-9 |
| 37489 | Result | In Process |
| 37490 | Interpretation | In Process |
| 37491 | Additional Information | 48767-8 |
| 37492 | Specimen | 31208-2 |
| 37493 | Source | 31208-2 |
| 37494 | Released By | 18771-6 |
Forms
1. CYP21A2 Gene Testing for Congenital Adrenal Hyperplasia Patient Information (T663) is required and available in Special Instructions
2. New York Clients: Informed consent is required. Please document on the request form or electronic order that a copy is on file. An Informed Consent for Genetic Testing (T576) is available in Special Instructions.
3. If not ordering electronically, complete, print, and send an Inborn Errors of Metabolism Test Request (T798) with the specimen.