Adrenoleukodystrophy (ALD) is an inherited disease in which there is a build-up of fatty substances known as 'very long chain fatty acids' (VLCFAs) in tissues around the body, mainly in the brain and spinal cord and in the adrenal glands, the small glands located above the kidneys.

The condition, which affects mostly males, is caused by abnormalities in a gene called ABCD1 which is responsible for the production of the protein needed to break down VLCFAs and prevent them from accumulating in tissues.

In the brain and spinal cord, the build-up of VLCFAs damages the protective sheath (myelin) around the nerves, causing a wide range of neurological problems that usually worsen over time. In the adrenal glands, the build-up prevents the glands from functioning properly and reduces their ability to produce hormones such as cortisol. Symptoms of the condition include behavioural problems, problems with vision, hearing and coordination, seizures (fits) and dementia.

ALD is a life-threatening and long-term debilitating condition due to the progressive damage to the brain and nerves.