We found that in the cerebellum, a region vulnerable to degeneration in PSP, nearly every gene in the 17q21.31 locus was differentially expressed, including MAPT, KANSL1, NSF, PLEKHM1, ARL17B, LRRC37A, and ARHGAP27. The only genes at the locus that were not differentially expressed were ARL17A and CRHR1. In the temporal cortex, which is typically unaffected by PSP, there was differential expression of KANSL1, PLEHKM1, LRRC37A, and ARGHAP27. MAPT was not differentially expressed in this region but showed a trending increase in expression (p = 0.06, FDR adjusted). The gene discussed is ARHGAP27; the disease is supranuclear palsy, progressive, 1.