Azoospermia is the extreme form of male infertility due to the absence of sperm in the semen. In order to help couples become parents, it is necessary to do a testicular biopsy to retrieve live spermatozoa that can later be used for in vitro fertilization with intra cytoplasmic micro-injection or ICSI. However, this is an invasive surgical operation with a potential deleterous long-term effect due to a testosterone deficit. Even though the chances of finding live spermatozoa is high, close to 95% for obstructive azoospermia and 40% if the defect comes from the testicules and is non-obstructive. However, today no clinical and/or biological criteria exist that allow the evaluation of the chances to find spermatozoa in the latter situation.

A study published in Human Reproduction evaluated the relevancy of Whole Exome Sequencing (WES) analysis in patients for which a first testicular biopsy had been performed, revealing a homogenous blockage in sperm maturation during prophase I of meiosis. Scientists from the Reproductive, Environmental, Epigenetic and Developmental Biology Unit (BREED (UVSQ/UPSaclay, Poissy)) showed that after validation by immunohistochemistry, that this approach was more relevant than Target Sequencing (TS), with a genetic cause identified that explains the testicular phentoype in more than 50% of the patients and 100% inbred patients. In addition, these preliminary results showed that this analysis provides arguments to avoid performing a 2nd testicular biopsy in these patients, or even a 1st biopsy in inbred patients, and this despite interpretation problems and so-called incidental findings generated by this analysis.

Contacts :

• Béatrice Mandon-Pépin (BREED) : beatrice.mandon-pepin@inrae.fr

• François Vialard (BREED) : francois.vialard@inrae.fr