Several large‐scale genome‐wide association studies8, 9 have identified single‐nucleotide polymorphisms associated with PD risk in regulatory regions of 2‐amino‐3‐carboxymuconic‐6‐semialdehyde decarboxylase (ACMSD), an enzyme in the kynurenine pathway that directly regulates the production of QUIN. The gene discussed is ACMSD; the disease is Parkinson disease.