In patients with cerebral small vessel disease and patients with Parkinson's disease, abnormality in serum inflammatory and lipoprotein markers, including trefoil factor 3, cholinesterase activity, homocysteine, lipoprotein cholesterol, lipoprotein-associated phospholipase A2, and superoxide dismutase, have been reported to be predictive of cognitive impairment or disease severity (Zou et al., 2018; Ahmadi Rastegar et al., 2019; Zhu et al., 2019; Wang et al., 2020; Yang et al., 2020). The gene discussed is BCHE; the disease is Parkinson disease.