These observations raise the possibility that UBQLN2 is a common catalyst for multiple aggregation-prone proteins, providing a mechanistic link to the frequent co-occurrence of α-syn and tau pathologies in PD (Cisbani et al, 2017; Smith et al, 2019) and to evidence that tau accelerates α-syn aggregation (Pan et al, 2022). This evidence concerns the gene MAPT and Parkinson disease.