Mitochondrial and ER proteins (e.g., PERK, IRE1, eiF2α, BiP, CHOP, GRP78, XBP1, ATF6, and ATF4) are known to be altered in diverse neurodegenerative diseases, and may be similarly aberrant in cardiac tissue, leading to protein aggregation and cardiomyopathy. The gene discussed is HSPA5; the disease is cardiomyopathy.