We found significantly lower endogenous plasma PACAP-38 levels in MM patients (n = 66, mean: 208.4 +/− 103.8 pg/mL) compared to healthy controls (C) (n = 10, mean: 311.7 +/− 82.19 pg/mL) (p = 0.0012) (Figure 1). Here, ADCYAP1 is linked to Miyoshi myopathy.