AZFa and candidate genes:
The size of the AZFa region is estimated to be 1Mb. The frequency of deletions in AZFa is lower than that of both AZFb and AZFc.
The important candidate genes include USP9Y (ubiquitin- specific protease 9, Y chromosome) and DBY (dead box on the Y).
USP9Y is a single copy
DBY is ubiquitously expressed in humans. In addition it exhibits transcripts unique to the
The other candidate genes include UTY (ubiquitous TPR motif on the Y) and TB4Y (thymosin B4-isoform).