Instead, in PPMS cases, the PAC1 immunosignals correlated well with the transcript levels and were significantly reduced compared with non-MS cases (**** p < 0.0001); however, this was not seen in SPMS cases, as PAC1-IR was similar to non-MS controls (p = 0.121). The gene discussed is ADCYAP1R1; the disease is primary progressive multiple sclerosis.