RBCK1 (HOIL-1) deficiency can manifest either as an autosomal recessive lethal immunodeficiency with autoinflammation and polyglucosan accumulation in muscle, heart, and liver or as polyglucosan body myopathy type 1 (PGM) with severe dilated cardiomyopathy and polyglucosan bodies found in skeletal muscle and heart [64]. The gene discussed is RBCK1; the disease is polyglucosan body myopathy 1 with or without immunodeficiency.