In addition it has also been shown to play a key role in the unfolded protein response (UPR) and has in fact been implicated in the retention of misfolded COMP in the chondrocytes of pseudoachondroplasia (PSACH) and MED patients resulting from mutations in the type III repeats of COMP [Hecht et al., 2001]. The gene discussed is COMP; the disease is pseudoachondroplasia.