Adrenoleukodystrophy (ALD) is a rare inherited genetic disorder that affects the adrenal glands, white blood cells, and the myelin sheath, which is a protective coating that surrounds nerve cells in the brain. ALD is a progressive disorder that affects the nervous system and can lead to additional physical and mental disabilities, including loss of vision, hearing, and intellectual functioning. ALD is caused by a mutation in the ABCD1 gene, which is responsible for the production of a protein known as ALDP. This protein helps to break down long-chain fatty acids, which are used to make the myelin sheath. Without the ALDP protein, these fatty acids build up in the body and cause damage to the myelin sheath. This damage can lead to the symptoms of ALD.