26410 Sex-Determining Region Y, Yp11.3 Deletion, FISH (SRYF)

​​Sex Determining Region of Y

This test includes a charge for the probe application, analysis, and professional interpretation of results for one probe set (2 individual fluorescence in situ hybridization probes). Analysis charges will be incurred based on the number of cells analyzed per probe set. If no cells are available for analysis, no analysis charges will be incurred. Additional charges will be incurred for application of all reflex probes performed.

Appropriate ancillary probes may be performed at consultant discretion to render comprehensive assessment. Any additional probes will have the results included within the final report and will be performed at an additional charge.

Detecting the deletion or addition of the SRY gene in conjunction with conventional chromosome studies (CHRCB / Chromosome Analysis, Congenital Disorders, Blood)

This test is appropriate to aid in detecting the presence or absence of the SRY gene in patients with either a 46,XX karyotype and phenotypically normal male external genitalia or a 46,XY karyotype and phenotypically normal female external genitalia. Testing must be ordered in conjunction with conventional chromosome studies (CHRCB / Chromosome Analysis, Congenital Disorders, Blood; or CHRAF / Chromosome Analysis, Amniotic Fluid).​

Submit only 1 of the following specimens:

This test must be ordered in conjunction with conventional chromosome studies (CHRCB / Chromosome Analysis, Congenital Disorders, Blood).

Provide a reason for referral with each specimen. The laboratory will not reject testing if this information is not provided, but appropriate testing and interpretation may be compromised or delayed

Amniotic fluid:

Collection Instructions:

1. Optimal timing for specimen collection is during 14 to 18 weeks of gestation, but specimens collected at other weeks of gestation are also accepted. Provide gestational age at the time of amniocentesis.

2. Discard the first 2 mL of amniotic fluid.

3. If ordering with CMAP / Chromosomal Microarray, Prenatal, Amniotic Fluid/Chorionic Villus Sampling, submit a minimum of 12 mL

4. If ordering with CHRAF / Chromosome Analysis, Amniotic Fluid, submit a minimum of 12 mL.

5. If ordering with both CMAP and CHRAF, submit a minimum of 26 mL.

Additional Information:

1. Unavoidably, about 1% to 2% of mailed-in specimens are not viable.

2. Bloody specimens are undesirable.

3. If the specimen does not grow in culture, you will be notified within 7 days of receipt.

4. Specimen cannot be frozen.

Autopsy:

Collection Instructions:

1. Wash biopsy site with an antiseptic soap.

2. Thoroughly rinse area with sterile water.

3. Do not use alcohol or iodine preparations.

4. Biopsy specimens are best taken by punch biopsy to include full thickness of dermis.

Whole Blood:

Collection Instructions:

1. Invert several times to mix blood.

2. Send whole blood specimen in original tube. Do not aliquot.

3. Other anticoagulants are not recommended and are harmful to the viability of the cells.

4. Cord blood is acceptable

Additional Information:

3. If the specimen does not grow in culture, you will be notified within 7 days of receipt.

4. Specimen cannot be frozen.

Chorionic villus:

Collection Instructions:

1. Collect specimen by the transabdominal or transcervical method.

2. Transfer chorionic villi to a Petri dish containing transport medium (T095).

3. Using a stereomicroscope and sterile forceps, assess the quality and quantity of the villi and remove any blood clots and maternal decidua.

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​Products of conception or stillbirth:

Collection Instructions: If a fetus cannot be specifically identified, collect villus material or tissue that appears to be of fetal origin.

Additional Information: Do not send entire fetus.

Skin biopsy:

Collection Instructions:

1. Wash biopsy site with an antiseptic soap.

2. Thoroughly rinse area with sterile water.

3. Do not use alcohol or iodine preparations.

4. A local anesthetic may be used.

5. Biopsy specimens are best taken by punch biopsy to include full thickness of dermis.

​Because this FISH test is not approved by the U.S. Food and Drug Administration, it is best used as an adjunct with other established methods to a confirm SRY deletions/duplications, such as existing clinical history or physical evaluation.

This test is not designed to detect low-level mosaicism.

Chromosomal microarray (CMACB / Chromosomal Microarray, Congenital, Blood or CMAP / Chromosomal Microarray, Prenatal, Amniotic Fluid/Chorionic Villus Sampling) may be the more appropriate test to detect unbalanced translocations, deletions or duplications.   

Interfering factors

-Cell lysis caused by forcing the blood quickly through the needle

-Use of an improper anticoagulant or improperly mixing the blood with the anticoagulant

-Excessive transport time

-Inadequate amount of specimen may not permit adequate analysis

-Improper packaging may result in broken, leaky, and contaminated specimen during transport

-Exposure of the specimen to temperature extremes (freezing or >30 degrees C) may kill cells and interfere with attempts to culture cells

-In prenatal specimens, a bloody specimen may interfere with attempts to culture cells and contamination by maternal cells may cause interpretive problems

This test is appropriate for individuals with a 46,XX karyotype and male sex external genitalia, a 46,XY karyotype and female sex external genitalia, clinical features suggestive of 46,XX testicular disorder of sex development with normal male sex external genitalia, and clinical features suggestive of 46,XY complete gonadal dysgenesis.

The SRY (sex-determining region on the Y chromosome) gene is required for normal embryonic wolffian (male sex) genital development, although numerous other genes are involved in completing the process of normal phenotypic male development. Some gene variants block the action of SRY in development. Thus, a 46,XY individual with an SRY deletion or variant will have a normal female phenotype, and a 46,XX individual with translocation of SRY to one X chromosome will have a normal male phenotype. Structural abnormalities of the Y chromosome result in a spectrum of abnormalities from primary infertility (regardless of sex) to various forms of ambiguous genitalia. SRY-negative 46,XX individuals often have ambiguous genitalia, whereas those who are positive for SRY usually have a normal male phenotype with azoospermia. SRY-negative 46,XY phenotypic females may have another genetic variant, such as a SOX9 gene variant.

A combination of conventional chromosome studies (CHRCB / Chromosome Analysis, Congenital Disorders, Blood; or CHRAF / Chromosome Analysis, Amniotic Fluid) to detect Y chromosome abnormalities and rule out other chromosome abnormalities or translocations, and fluorescence in situ hybridization studies to detect cryptic translocations involving the SRY region that are not demonstrated by conventional chromosome studies are recommended.

​An interpretive report will be provided.​

​Any phenotypic male individual with an SRY signal on a structurally normal Y chromosome is considered negative for a deletion in the region tested by this probe. Any patient with a FISH signal pattern indicating loss of the critical region will be reported as having a deletion of the regions tested by this probe. Any patient with a FISH signal on an X chromosome will be reported as having a cryptic X;Y translocation involving the critical region.