For example, a Pennsylvania cohort identified four serum proteins—bone sialoprotein (BSP), osteomodulin (OMD), aminoacylase-1 (ACY1), and growth hormone receptor (GHR)—as PD biomarkers, yet these were not specific to PD when compared to ALS or mild cognitive impairment [41]. The gene discussed is ACY1; the disease is Cognitive impairment.