Some investigators have reported on levels of what is most probably SCC-Cu in Alzheimer's disease,49,50 using an assay for “free” or “non-ceruloplasmin” Cu developed by Squitti and colleagues.49 (Some assays for “free” or “non-ceruloplasmin” Cu use a different approach that is not measuring SCC-Cu.51,53) Thus, SCC levels may be related to physiological conditions other than Cu overload, or reflect other perturbations of the homeostasis of this metal. Here, CP is linked to early-onset autosomal dominant Alzheimer disease.