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HelpTest Code YMCRO Y Chromosome Microdeletions, Molecular Detection, Varies
Useful For
Evaluating men with azoospermia, severe oligozoospermia, or otherwise unexplained male factor infertility
Genetics Test Information
Tests for the presence of microdeletions in the AZFa, AZFb, and AZFc regions of the Y chromosome.
Method Name
Polymerase Chain Reaction (PCR)
Reporting Name
Y MicrodeletionSpecimen Type
VariesShipping Instructions
Specimen preferred to arrive within 96 hours of collection.
Specimen Required
Patient Preparation: A previous bone marrow transplant from an allogenic donor will interfere with testing. Call 800-533-1710 for instructions for testing patients who have received a bone marrow transplant.
Specimen Type: Whole blood
Container/Tube:
Preferred: Lavender top (EDTA) or yellow top (ACD)
Acceptable: Any anticoagulant
Specimen Volume: 3 mL
Collection Instructions:
1. Invert several times to mix blood.
2. Send whole blood specimen in original tube. Do not aliquot.
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Varies | Ambient (preferred) | ||
| Frozen | |||
| Refrigerated | |||
Reject Due To
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.Clinical Information
Yq microdeletions involving some or all of the azoospermic factor (AZF) region are the most frequently identified cause of spermatogenic failure in chromosomally normal men with nonobstructive azoospermia (3%-15%) or severe oligospermia (6%-10%). Among unselected infertile men, the overall frequency of Yq microdeletions is approximately 3%. The relative frequency of Yq microdeletions makes the evaluation for them an important aspect of the diagnostic work up in infertile men, especially those with azoospermia or severe oligospermia.
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Most cases of Yq microdeletions occur de novo, and due to the consequential infertile phenotype, they are typically not transmitted. However, in cases where assisted reproductive technology (example: testicular sperm extraction followed by intracytoplasmic sperm injection) is used to achieve viable pregnancy, all male offspring born to a microdeletion carrier will carry the deletion and may be infertile.
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Men testing positive for 1 or more microdeletions who are enrolled in an in vitro fertilization treatment program may wish to consider alternative options to intracytoplasmic sperm injection (eg, donor sperm) and consultation with an experienced reproductive endocrinologist and medical geneticist is recommended.
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Most Y microdeletions are the result of homologous recombination between repeated sequence blocks. Testing for deletions involves investigating for the presence or absence of markers located within nonpolymorphic regions of the AZF region.
Interpretation
An interpretive report will be provided.
Cautions
This assay will not detect all of the causes of infertility or azoospermia. Therefore, the absence of a detectable microdeletion does not rule out the presence of other genetic or nongenetic factors that may be the cause of clinical findings.
Test results should be interpreted in the context of clinical findings, family history, and other laboratory data. Errors in the interpretation of results may occur if information given is inaccurate or incomplete.
Rare variants (ie, polymorphisms) exist that could lead to false-negative or false-positive results. If results obtained do not match the clinical findings, additional testing should be considered.
In rare cases, DNA alterations of undetermined significance may be identified.
A genetic consultation is recommended for all patients undergoing this testing. Additional consultation with a reproductive endocrinologist/urologist to discuss reproductive options is recommended when a deletion is detected.
Supportive Data
Validation studies done at Mayo Clinic on a series of known fertile and infertile specimens provided the following results. Of 111 DNA specimens from known fertile men, 110 gave unequivocal negative results demonstrating clinical specificity of 99%. A series of 19 specimens from females (negative controls) were all negative, as expected. In a small series of specimens from 4 men being treated for male factor infertility, no deletions were found (which may be expected given a reported prevalence of 7% for microdeletions in unselected male infertility patients). Seven specimens were mailed in from outside laboratories (3 of which were sent as part of an external quality assessment scheme organized by the European Academy of Andrology) with known deletions in either AZFa, AZFb, or AZFc. Using this assay, all were diagnosed correctly to give an analytical sensitivity of 100%.
Clinical Reference
1. Stahl PJ, Masson P, Mielnik A, et al: A decade of experience emphasizes that testing for Y microdeletions is essential in American men with azoospermia and severe oligozoospermia. Fertil Steril. 2010 Oct;94(5):1753-1756
2. Shalender Bhasin: Approach to the infertile man. J Clin Endocrinol Metab. 2007Jun; 92(6):1995-2004
3. Ferlin A, Arredi B, Speltra E, et al: Molecular and clinical characterization of Y chromosome microdeletions in infertile men: A 10-year experience in Italy. J Clin Endocrinol Metab. 2007 Mar;92(3):762-770
Method Description
Multiplex polymerase chain reaction and agarose gel electrophoresis are used to test DNA for the presence of microdeletions in the AZFa, AZFb, and AZFc regions of the Y chromosome.(Simoni M, Bakker E, Krausz C: EAA/EMQN best practice guidelines for molecular diagnosis of y-chromosomal microdeletions. State of the art 2004 Int J Androl 2004;Aug 27[4]:240-249)
Day(s) Performed
Wednesday
Report Available
7 to 10 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
CPT Code Information
81403-DAZ/SRY (deleted in azoospermia and sex determining region Y) (eg, male infertility), common deletions (eg, AZFa, AZFb, AZFc, AZFd)
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| YMCRO | Y Microdeletion | 35456-3 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 53364 | Result Summary | 50397-9 |
| 53365 | Result | 82939-0 |
| 53366 | Interpretation | 69047-9 |
| 53367 | Specimen | 31208-2 |
| 53368 | Source | 31208-2 |
| 53369 | Released By | 18771-6 |
Special Instructions
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.Forms
1. New York Clients-Informed consent is required. Document on the request form or electronic order that a copy is on file
-Informed Consent for Genetic Testing (T576)
-Informed Consent for Genetic Testing-Spanish (T826)
2. Molecular Genetics: Congenital Inherited Diseases Patient Information (T521)
Specimen Minimum Volume
1 mL