CRISP1 and Azoospermia: CRISP1 is an epididymal protein that binds to the postacrosomal region of the sperm head and plays a role in the regulation of sperm motility, acrosome reaction and sperm–egg fusion; its validity as a biomarker of azoospermia has been further confirmed by Western blot analysis [118] showing that CRISP1 is absent or present at very low levels in samples from patients with OA.