SDF-1 alpha and TNF-RII, in particular, have been identified as potential serum biomarkers for LRRK2 mutation carriers, though not to the extent of differentiating LRRK2+/PD from LRRK2-/PD or LRRK2+/UC from LRRK2-/UC. Here, LRRK2 is linked to Parkinson disease.