CSF MPO activity was found not to be significantly different in male and female patients at early-stage PD (men, 0.0291 ± 0.001 mU/mL, n = 12; women, 0.0284 ± 0.001 pg/mL, n = 10) relative to patients with moderate-advanced PD (men, 0.0301 ± 0.0003 mU/mL, n = 6; women, 0.0289 ± 0.001 mU/mL pg/mL, n = 6). The gene discussed is MPO; the disease is Parkinson disease.