Examination of specific AD risk loci revealed that 5x‐CC006 and 5x‐CC013 harbored the same founder strain contributions for the following genes: Rbck1 (PWK/PhJ), Jazf1 (NZO/HILtj), Tpcn1 (NZO/HILtj), Idua (NZO/HILtj), Inpp5d (129S1/SvlmJ), Wdr81 (NOD/ShiLtJ), Abi3 (NOD/ShiLtJ), Ace (NOD/ShiLtJ), Wnt3 (NOD/ShiLtJ), Mapt (NOD/ShiLtJ), Grn (NOD/ShiLtJ), Ctsh (C57BL/6J), Clu (129S1/SvlmJ), Ctsb (129S1/SvlmJ), Zcwpw1 (129S1/SvlmJ), and Pilra (129S1/SvlmJ). The gene discussed is CTSB; the disease is Alzheimer disease.