The expression of β-repressor protein 1 (ARRB1) and β-repressor protein 2 (ARRB2) in microglia is reciprocally regulated, and Fang found that ARRB1 ablation ameliorated the pathological features of PD, whereas ARRB2 knockout aggravated the pathological features of PD (Fang et al., 2021). This evidence concerns the gene ARRB2 and Parkinson disease.