HMGCR and X-linked adrenoleukodystrophy: As expected, conditions of low cholesterol (LDM) induced a robust increase in HMGCR expression compared with complete medium (Control, p < 0.0001; X-ALD, p = 0.0023), whereas cholesterol loading (LDM + high-cholesterol) reduced the expression of HMGCR in both X-ALD (p = 0.0001) and control fibroblasts (p = 0.0050) (Supplementary Table S5).