Symbol AZF1 Entrez 560 Locus Chr. Y q11 | Alt. symbols AZF HUGO 908 | |
Azoospermia factor (AZF) refers to one of several proteins or their genes, which are coded from the AZF region on the human male Y chromosome. Deletions in this region are associated with inability to produce sperm. Subregions within the AZF region are AZFa (sometimes AZF1), AZFb and AZFc (together referred to as AZF2). AZF is the term used by the HUGO Gene Nomenclature Committee.
Contents
AZF1
AZF1 (Azoospermia Factor 1) gene is likely located in the euchromatic part of the long arm in Yq11.23. AZF1 is 792kb long and just distal to the centromere of the Y chromosome. AZF1 genes are involved in spermatogenesis in the testes.
AZF2
Originally, an AZFb and AZFc genes were identified and thought to be separate regions. They were later found to be overlapping and are now referred to as AZF2.
AZFc
AZFc is one of the most genetically dynamic regions in the human genome, possibly serving as counter against the genetic degeneracy associated with the lack of a partner chromosome during meiosis. However, such strategy comes has the adverse effects that some rearrangements represent a risk factor or a de facto causative agent of spermatogenic disruption.
A specific partial deletion of AZFc called gr/gr deletion is significantly associated with male infertility among Caucasians in Europe and the Western Pacific region.
AZF mutations
Mutations or deletions in the AZF genes are associated with inability or lessened ability to create sperm. It may cause azoospermia (not having any measurable level of sperm in semen). Deletions in the USP9Y gene, which is located within AZF1, are usually but not always associated with inability to form sperm.