In addition, given a previous study showing that SOX9 expression declines rapidly after WT1 deletion in mice (Chen et al., 2013), we infer that WT1-silencing in primate Sertoli cells may also result in a cell fate shift, which in turn causes age-associated loss of functional Sertoli cells and consequent testicular degeneration. The gene discussed is WT1; the disease is Testicular atrophy.