PPP2R2B and Parkinson disease: PPP2R22B encodes the Serine/threonine-protein phosphatase 2A 55 kDa regulatory subunit B beta isoform, which is also a protein phosphatase involved in the negative control of cell growth and division, and has been reported to be downregulated in PD (Mayer et al., 1991; Cheng et al., 2009; Kim et al., 2017).