KCNJ15 and Parkinson disease: This genetic evidence strongly suggests that the KCNJ15‐encoded protein, the inwardly rectifying potassium channel Kir4.2, may play a significant role in PD pathobiology, similar to other well‐known genetic mutations such as LRRK2p.G2019S, which contributes to disease with intermediate penetrance (Hernandez et al., 2016; Trinh et al., 2014).