A recent comprehensive lipidomic study of serum and cerebrospinal fluid from large, multicentre cohorts of PD patients (and matched controls) with and without the LRRK2 G2019S mutation has revealed that LRRK2-PD patients have unique lipid profiles differing from those of idiopathic PD patients and healthy controls. The gene discussed is LRRK2; the disease is Parkinson disease.