Intriguingly, however, a comparatively understudied isoform (CLU Isoform 2), which is reported to be selectively overexpressed in individuals carrying the AD-protective minor rs11136000T allele,[44] encodes an ApoJ proteoform containing three additional Cys residues in the extreme N-terminus [36] (referred to here as ApoJ2) (Fig 3B). Here, CLU is linked to Alzheimer disease.