RAB39B and Parkinson disease: Moreover, relative quantification by qRT-PCR showed that the relative copy number of RAB39B expression in our 195 PD individuals was between 0.8–1.2 in female PD patients and 0.45–0.6 in male PD patients, which meant that there were no dosage mutations (such as large and complex rearrangements mutations) in RAB39B gene among our familial PD patients.