Penetrance differences were observed in the quantity of each acyl-CoA species, although mono- and di-unsaturated VLCFA-CoA species were significantly accumulated in all three ABCD1-KO HeLa cells (Fig. 3B, Table 4), as was likely observed in the X-ALD fibroblasts (Fig. 2A, Table 2). The gene discussed is ABCD1; the disease is X-linked adrenoleukodystrophy.