PTCD2 and Alzheimer disease: Another study showed that sera from PD patients contained disease-specific auto-antibodies, because characteristic alterations of 10 auto-antibodies could distinguish PD from normal aging, Alzheimer’s disease (AD), multiple sclerosis, and breast cancer with accuracies over 85%, and these 10 auto-antitbodies included PTCD2, HSH2D, Myotilin, Elongation factor 1-alpha 1, ICAM4, FRMD8, CTLA-4/Fc, PABPC3, Fibronectin 1, and TRIM21 (Han et al., 2012).