CD9 and prion disease: Many genes in Table 1 were linked to prion diseases in previous studies, such as cathepsin D [12], cathepsin B [13], Inositol 1,4,5-triphosphate receptor [13], apolipoprotein D [13], vimentin [12], [13], heat shock protein 70 [14], transferrin [15], reticulum 1 [16], reticulum 3 [17], a gene similar to solute carrier family 25 [13], CD9 [13], [18], vacuolar protein sorting 11 homolog [11] and DnaJ [11].