From 2005 to 2007 Curis and Procter & Gamble collaborated on developing a topical hedgehog agonist for hair loss; the agent did not meet safety standards, and the program was terminated.   In 2008 researchers at the University of Bonn announced they have found the genetic basis of two distinct forms of inherited hair loss. They found the gene P2RY5 causes a rare, inherited form of hair loss called hypotrichosis simplex. It is the first receptor in humans known to play a role in hair growth.    Researchers found that disruption of the gene SOX21 in mice caused cyclical hair loss. Research has suggested SOX21 as a master regulator of hair shaft cuticle differentiation, with its disruption causing cyclical alopecia in mice models.  Deletion of SOX21 dramatically affects hair lipids.