It would be important to also apply it to longitudinal data to confirm increased levels of PPIB and IGKV6‐21 in PD patients and VGF as a potential indicator for disease manifestation in LRRK2 G2019S carriers but also identify new biomarkers for PD risk and disease progression in idiopathic and genetic forms of PD. Here, LRRK2 is linked to Parkinson disease.