Finally, we determined the expression levels of miR-335 in serum samples of 40 iPD patients, 41 LRRK2-PD patients and 40 healthy controls, and confirmed that miR-335 was significantly reduced in the sera of iPD and LRRK2-PD patients in comparison with control subjects (Figure 1C). The gene discussed is LRRK2; the disease is Parkinson disease.