SRY Deletion, FISH

What is the SRY Deletion FISH test?

The SRY Deletion FISH (Fluorescence In Situ Hybridization) test is used to detect the presence or absence of the SRY gene, located on the Y chromosome. This gene is essential for male sex differentiation. The test is particularly relevant in cases of ambiguous genitalia, disorders of sex development (DSDs), and suspected Y chromosome microdeletions.


Why is this test done?

This test is crucial in evaluating disorders of sexual development. It helps determine genetic sex when there is discordance between physical appearance and chromosomal findings. It is also used in infertility evaluations, particularly in males with azoospermia or severe oligospermia.


How is the test performed?

A blood or tissue sample is collected and treated with fluorescent probes that specifically bind to the SRY gene region on the Y chromosome. Under a fluorescent microscope, the presence or absence of the fluorescent signal indicates whether the SRY gene is present.


What do the results mean?

A positive result (presence of the SRY gene) confirms the existence of the gene and typically supports a male genotype. A negative result (absence of the SRY gene) may explain certain intersex conditions and helps in diagnosing DSDs. The results are interpreted alongside clinical findings and other genetic tests.


Are there any precautions or preparations required?

No special preparation is required for the patient. The test requires a proper sample and must be processed in a specialized cytogenetics laboratory.