USP9Y and male infertility: In addition, independent of deciphering the genetic key component of complete AZFa deletions, DDX3Y is immediately a disease gene for male infertility with a clear gene-disease relationship, and patients with unexplained NOA should be screened not only for AZFa deletions but also for single nucleotide variants in DDX3Y. Consequently, DDX3Y should be included in any gene-panel for clinical diagnostic of azoospermia and should preferably be analyzed via WES because of the quickly increasing number of validated azoospermia genes37.