ACBD5 and X-linked adrenoleukodystrophy: However, given the subtle phenotypic differences between ACBD5-deficient patients compared to those with VLCFA import defects (e.g., X-ALD), it is plausible that loss of ACBD5’s direct peroxisome-ER tethering role could be impacting on the pathophysiology, e.g., through changes to peroxisome dynamics/distribution or cooperative peroxisome-ER lipid metabolism.