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Y-Chromosome Study

Results usually available in 7-10 working days.

Y-chromosome infertility is inherited in a Y-linked manner. Since males with deletion of the AZF (azoospermia factor) regions of the long arm of the Y chromosome are infertile, the deletions are usually de novo and therefore not present in the father of the proband. Rarely, within a family, the same deletion of the Y chromosome can cause infertility in some males but not others; hence, some fertile males with deletion of the AZF regions have fathered sons who are infertile. Pregnancies have been achieved from males with infertility caused by deletion of the AZF regions using intracytoplasmic sperm injection (ICSI). Male fetuses have the same deletion as their father, with a high risk of male infertility. Female fetuses from a father with a Y chromosome deletion have no increased risk of congenital abnormalities or infertility. In pregnancies conceived through assisted reproductive technology (ART) and known to be at risk of resulting in a male with Y chromosome deletion, specific prenatal testing or preimplantation testing could be performed to determine the sex of the fetus and/or the presence of the Y chromosome deletion.

SRY, the gene that encodes the sex-determining region Y protein, is the only gene known to be associated with XX male syndrome; at least one more as yet unknown gene at another locus is implicated. Approximately 80% of individuals with the XX male syndrome are SRY-positive. Microdeletions of the long arm of the Y chromosome (Yq) in the AZF regions associated with male infertility usually result in the deletion of multiple genes. A rare single gene abnormality in USP9Y can also be associated with male infertility.

The lab tests for the presence of both the AZF and SRY genes by PCR amplification.