Hello Seyed,

Extensive work has been done on the causes of Azoospermia, Oligozoospermia and Teratozoospermia from the last two decades...Its really difficult to suggest you particular paper as reference...Go to NCBI, Gene Bank you can find the entire details regrading the genes involved in Azoo,Oligo,Terato etc...

Pretesticular azoospermia may be caused by congential hypopituitarism, Kallmann syndrome, Prader-Willi syndrome and other genetic conditions that lead to GnRH or gonadotropin deficiency. Testicular azoospermia is seen in Klinefelter syndrome(XXY) and the XX male syndrome. In addition, 13% of men with azoospermia have a defective spermatogenesis that is linked to defects of the Y chromosome.[12] Such defects tend to be de novo micro-deletions and affect usually the long arm of the chromosome. A section of the long arm of the Y chromosome has been termed Azoospermia Factor (AZF) at Yq11 and subdivided into AZFa, AZFb, AZFc and possibly more subsections. Defects in this area can lead to oligospermia or azoospermia, however, a tight genotype-phenotype correlation has not been achieved.[12] Spermatogenesis is defective with gene defects for the androgen receptor.

Regards,

Sanketh Dhumal

Key references to look up are by Reijo et al., Kent-First, et al., and a host of others.  These are good starts.  I would also refer you to Promega to their YDDS-2 which generally provides good coverage of the key regions of the Y-chromosome AZF regions with controls.  There are new markers that can be added as well to make the system even more accurate.  

Not much has has been done in the genetic components or origin of azospermia in Nigeria. We are currently working on the DNA fragmentation Index of infertile men. From here we may move up to the genetic origin. On the other hand, a collaboration with Specialist will be an added value to this problem among Africans.