More specifically, it has previously been shown that MCDS and EDM5 share a common disease signature consistent with a classical UPR and defined by an upregulation of ATF6, alternative splicing of Xbp1 and an increase in Canx, Creld2, Derl3, Dnajc3, Hyou1, Manf, Pdia3, Pdia4, Pdia6 and Xbp1 gene expression [32]. The gene discussed is PDIA4; the disease is Schmid metaphyseal chondrodysplasia.