Since a candidate variation in PED.25 was located in the SORL1 gene (p.Arg1303Cys) we characterized the expression pattern of SORL1 in the two affected family members and compared it to sporadic AD cases and controls using immunohistochemistry with four different SORL1 antibodies (Additional file 2: Table S1). Here, SORL1 is linked to Alzheimer disease.