Differential expression analysis verified that TMEM175 was significantly downregulated in the midbrains of PD patients (p = 1.19E‐02), and further exploration revealed that TMEM175 was also dramatically downregulated in the substantia nigra of PD patients (p = 1.16E‐02) and incidental Lewy body disease patients (p = 7.52E‐03). This evidence concerns the gene TMEM175 and Lewy body dementia.