Consistent with the hypothesis that increased brain endothelium–leucocyte interactions caused by ABCD1-related endothelial upregulation of adhesion molecules leads to alterations in blood flow across capillaries, we found higher CTH in NAWM of asymptomatic ALD hemizygote patients compared to controls (Fig. 2). The gene discussed is ABCD1; the disease is adrenoleukodystrophy.