Test Catalog

Test ID: SRYF    
Sex-Determining Region Y, Yp11.3 Deletion, FISH

Useful For Suggests clinical disorders or settings where the test may be helpful

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

Genetics Test Information Provides information that may help with selection of the correct genetic test or proper submission of the test request

This test is appropriate to aid in detecting the presence or absence of the SRY gene in XX males and XY females. Testing must be ordered in conjunction with conventional chromosome studies (CHRCB / Chromosome Analysis, Congenital Disorders, Blood).

Testing Algorithm Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

This test includes a charge for application of the first probe set (2 FISH probes) and professional interpretation of results. Additional charges will be incurred for application of all reflex probes performed. 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.

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

This test is appropriate for individuals with a 46,XX karyotype and phenotypically normal male external genitalia, a 46,XY karyotype and phenotypically normal female external genitalia, clinical features suggestive of 46,XX testicular disorder of sex development with normal male 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) genital development, although numerous other genes are involved in completing the process of normal male development. Some gene mutations block the action of SRY in development. Thus, a 46,XY individual with an SRY deletion or mutation will develop as a female, and a 46,XX individual with translocation of SRY to 1 X chromosome will develop as a male. Structural abnormalities of the Y chromosome result in a spectrum of abnormalities from primary infertility (male or female) to various forms of ambiguous genitalia. SRY-negative 46,XX males often have ambiguous genitalia, whereas those who are positive for SRY usually have a normal male phenotype with azoospermia. SRY-negative 46,XY females may have another mutation, such as 1 involving the SOX9 gene.


We recommend conventional chromosome studies (CHRCB / Chromosome Analysis, Congenital Disorders, Blood) to detect Y chromosome abnormalities and to rule out other chromosome abnormalities or translocations, and FISH studies to detect cryptic translocations involving the SRY region that are not demonstrated by conventional chromosome studies.

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

An interpretive report will be provided.

Interpretation Provides information to assist in interpretation of the test results

Any 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.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

Because this FISH test is not approved by the U.S. Food and Drug Administration, it is important to confirm SRY deletions/duplications by other established methods, such as clinical history or physical evaluation.

Chromosomal microarray (CMAC / 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

Supportive Data

Using a probe for the SRY critical region, FISH analysis was performed on a series of 46 patient specimens, peripheral blood or amniotic fluid, and results were compared to cytogenetic analyses and the patient's phenotype.


Of 20 phenotypic females:

-12 with a 45,X karyotype or an X duplication exhibited no SRY signal

-8 with a 46,XY karyotype or an abnormal Y were SRY positive


Of 20 phenotypic males:

-7 of 8 with a 46,XX karyotype were SRY negative

-13 with a 46, XY with a normal or rearranged Y chromosome were SRY positive


Of 25 controls:

-13 males exhibited SRY on the Y chromosome

-12 females exhibited no SRY signal

Clinical Reference Recommendations for in-depth reading of a clinical nature

1. Ostrer H: 46,XY Disorder of Sex Development and 46,XY Complete Gonadal Dysgenesis. 2008 May 21 (Updated 2009 Sep 15). In: Pagon RA, Adam MP, Ardinger HH, et al., editors. GeneReviews (Internet). Seattle (WA): University of Washington, Seattle; 1993-2014. Available at http://www.ncbi.nlm.nih.gov/books/NBK1547/Accessed 05/27/2013

2. Vilain EJ: 46,XX Testicular Disorder of Sex Development. 2003 Oct 30 (Updated 2009 May 26). In: Pagon RA, Adam MP, Ardinger HH, et al, editors. GeneReviews (Internet). Seattle (WA): University of Washington, Seattle; 1993-2014. Accessed 05/27/2013. Available at http://www.ncbi.nlm.nih.gov/books/NBK1416/

Special Instructions Library of PDFs including pertinent information and forms related to the test