HSPA5 and cerebellar ataxia: For example, upregulation of UPR was observed in the woozy mutant mouse that exhibit cerebellar ataxia and PC loss due to mutation in the GRP78 nucleotide exchange factor gene Sil1, which was associated with the Marinesco-Sjögren syndrome in human [6], demonstrating that perturbation of ER chaperone function in PCs cause ER stress and subsequent PC degeneration [128, 129].