NRGN and Schnyder corneal dystrophy: Using initial study visit samples (earliest available sample from either the participant’s screening or baseline visit), there was a significant difference in median NRGN levels between the SCD (n = 101) and pediatric healthy control groups (n = 25), (0.28 vs. 0.12 ng/mL, 25–75%IQR: 0.11–0.83 vs. 0.09–0.15 ng/mL, p < 0.0004) (Figure 3).