HLA-DRB5 and Alzheimer disease: Since its discovery in 2013, one study has explored the role of HLA-DRB5, as well as 11 other newly discovered genetic risk factors (PTK2B, SORL1, SLC24A4, DSG2, INPP5D, MEF2C, NME8, ZCWPW1, CELF1, FERMT2, and CASS4), in AD pathogenesis.