Thus, mutations to the ABCD1 gene, of which over 900 have been catalogued in the ALD mutation database (https://adrenoleukodystrophy.info/) (accessed on 15 November 2021) [4], result in a deficiency in the ABCD1 protein and impaired degradation of VLCFA [5]. Here, ABCD1 is linked to adrenoleukodystrophy.