Using the Cre–LoxP system to generate two SC-specific mutants (raptor and Rheb knockout mice), the authors observed that adult raptor KO mice displayed azoospermia and disrupted cytoskeletal organization and cell polarity while adult Rheb KO mice had intact seminiferous tubules, sperm present in the epididymis and normal fertility [117]. The gene discussed is RPTOR; the disease is Azoospermia.