Van der Goot and coworkers [13] identified the L‐tryptophan (Trp)‐catabolizing enzyme tryptophan 2,3‐dioxygenase (TDO) (EC 1.13.11.11) as a potential drug target for PD in a genome‐wide RNA interference screen for regulators of aging‐related α‐synuclein toxicity in Caenorhabditis elegans. Here, TDO2 is linked to Parkinson disease.