CHGB and multiple system atrophy: In a study in PD, MSA, CBD, PSP, and healthy controls, a panel of four proteins (ubiquitin, β2-microglobulin, and 2 secretogranin 1 [chromogranin B] fragments) was identified which could differentiate PD and healthy controls on one side from APD on the other side with an AUC of 0.8 (Constantinescu et al., 2010a).