PSMB9 and Alzheimer disease: Immunoproteasome and its subunits have been linked to a variety of human diseases including central nervous system (CNS) diseases such as Alzheimer's (AD)11 and Huntington's diseases (HD).2, 12 In 2006, Mishto et al.11 first reported the presence and role of immunoproteasome and its LMP2 subunit polymorphism at codon 60 in AD.