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Genetics Home Reference: your guide to understanding genetic conditions     A service of the U.S. National Library of Medicine®


Reviewed January 2009

What is the official name of the USP9Y gene?

The official name of this gene is “ubiquitin specific peptidase 9, Y-linked.”

USP9Y is the gene's official symbol. The USP9Y gene is also known by other names, listed below.

What is the normal function of the USP9Y gene?

The USP9Y gene provides instructions for making a protein called ubiquitin-specific protease 9. This gene is found on the Y chromosome. People normally have 46 chromosomes in each cell. Two of the 46 chromosomes are sex chromosomes, called X and Y. Females have two X chromosomes (46,XX), and males have one X chromosome and one Y chromosome (46,XY).

Because it is located on the Y chromosome, the USP9Y gene is present only in males. It occurs in a region of the Y chromosome called azoospermia factor A (AZFA). Azoospermia is the absence of sperm cells. The USP9Y gene is believed to be involved in sperm cell development, but its specific function is not well understood.

Does the USP9Y gene share characteristics with other genes?

The USP9Y gene belongs to a family of genes called USP (ubiquitin-specific peptidases).

A gene family is a group of genes that share important characteristics. Classifying individual genes into families helps researchers describe how genes are related to each other. For more information, see What are gene families? ( in the Handbook.

How are changes in the USP9Y gene related to health conditions?

Y chromosome infertility - caused by mutations in the USP9Y gene

A small number of individuals with Y chromosome infertility have mutations in the USP9Y gene or deletions of all or part of the gene. These changes in the USP9Y gene prevent the production of ubiquitin-specific protease 9 or result in the production of an abnormally short, nonfunctional protein. The absence of functional ubiquitin-specific protease 9 impairs the production of sperm cells, resulting in an inability to father children.

Where is the USP9Y gene located?

Cytogenetic Location: Yq11.2

Molecular Location on the Y chromosome: base pairs 12,701,231 to 12,860,844

(Homo sapiens Annotation Release 107, GRCh38.p2) (NCBI (

The USP9Y gene is located on the long (q) arm of the Y chromosome at position 11.2.

The USP9Y gene is located on the long (q) arm of the Y chromosome at position 11.2.

More precisely, the USP9Y gene is located from base pair 12,701,231 to base pair 12,860,844 on the Y chromosome.

See How do geneticists indicate the location of a gene? ( in the Handbook.

Where can I find additional information about USP9Y?

You and your healthcare professional may find the following resources about USP9Y helpful.

You may also be interested in these resources, which are designed for genetics professionals and researchers.

What other names do people use for the USP9Y gene or gene products?

  • AZF
  • AZF1
  • AZFA
  • azoospermia factor 1
  • deubiquitinating enzyme FAF-Y
  • fat facets protein related, Y-linked
  • FLJ33043
  • SP3
  • ubiquitin specific peptidase 9, Y-linked (fat facets-like, Drosophila)
  • ubiquitin-specific processing protease FAF-Y
  • ubiquitin specific protease 9, Y chromosome (fat facets-like Drosophila)
  • ubiquitin specific protease 9, Y-linked
  • ubiquitin thiolesterase FAF-Y

See How are genetic conditions and genes named? ( in the Handbook.

What glossary definitions help with understanding USP9Y?

azoospermia ; cell ; chromosome ; enzyme ; gene ; infertility ; protease ; protein ; sex chromosomes ; sperm ; ubiquitin

You may find definitions for these and many other terms in the Genetics Home Reference Glossary.


  • Ferlin A, Arredi B, Speltra E, Cazzadore C, Selice R, Garolla A, Lenzi A, Foresta C. 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):762-70. Epub 2007 Jan 9. (
  • Hall NM, Brown GM, Furlong RA, Sargent CA, Mitchell M, Rocha D, Affara NA. Usp9y (ubiquitin-specific protease 9 gene on the Y) is associated with a functional promoter and encodes an intact open reading frame homologous to Usp9x that is under selective constraint. Mamm Genome. 2003 Jul;14(7):437-47. (
  • Krausz C, Degl'Innocenti S, Nuti F, Morelli A, Felici F, Sansone M, Varriale G, Forti G. Natural transmission of USP9Y gene mutations: a new perspective on the role of AZFa genes in male fertility. Hum Mol Genet. 2006 Sep 15;15(18):2673-81. Epub 2006 Aug 7. (
  • Lee KH, Song GJ, Kang IS, Kim SW, Paick JS, Chung CH, Rhee K. Ubiquitin-specific protease activity of USP9Y, a male infertility gene on the Y chromosome. Reprod Fertil Dev. 2003;15(1-2):129-33. (
  • NCBI Gene (
  • Oates RD. The genetic basis of male reproductive failure. Urol Clin North Am. 2008 May;35(2):257-70, ix. doi: 10.1016/j.ucl.2008.01.015. Review. (
  • Sun C, Skaletsky H, Birren B, Devon K, Tang Z, Silber S, Oates R, Page DC. An azoospermic man with a de novo point mutation in the Y-chromosomal gene USP9Y. Nat Genet. 1999 Dec;23(4):429-32. (
  • Tyler-Smith C. An evolutionary perspective on Y-chromosomal variation and male infertility. Int J Androl. 2008 Aug;31(4):376-82. doi: 10.1111/j.1365-2605.2008.00889.x. Review. (
  • Vogt PH, Falcao CL, Hanstein R, Zimmer J. The AZF proteins. Int J Androl. 2008 Aug;31(4):383-94. doi: 10.1111/j.1365-2605.2008.00890.x. Review. (
  • Wimmer R, Kirsch S, Weber A, Rappold GA, Schempp W. The Azoospermia region AZFa: an evolutionar y view. Cytogenet Genome Res. 2002;99(1-4):146-50. (


The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? ( in the Handbook.

Reviewed: January 2009
Published: February 1, 2016