With the FOCUS method, CD38 (P = 5.83E-12, TWAS-Z = −7.06), DGKQ (P = 1.86E-22, TWAS-Z = 0.46) and GPNMB (P = 1.40E-12, TWAS-Z = 5.61) in the brain were validated to be causal genes for PD regardless of the linkage disequilibrium (LD) and pleiotropy. The gene discussed is GPNMB; the disease is Parkinson disease.