Hyaluronidase degrades hyaluronic acid, which is an important structural proteoglycan found in basement membranes and also extracellular matrices. There are six members of the hyaluronidase family. Hyaluronidase PH20 is a GPI-anchored enzyme located on the human sperm surface and inner acrosomal membrane and plays a role in sperm penetration through the the hyaluronic acid-rich cumulus cell layer surrounding the oocyte. Abnormal expression of this gene has been implicated in degradation of b