What is ALD?
Adrenoleukodystrophy (ALD) is caused by a genetic fault that means those affected are unable to process Very Long Chain Fatty Acids (VLCFAs). It is thought that these VLCFAs accumulate and destroy the myelin sheath that covers the nerves in the body and brain. The myelin acts like the coating around an electric cable, and allows messages to be transmitted along nerve cells.
The gene at fault in ALD is called ABCD1. The faulty gene can cause several related but different conditions, such as Asymptomatic ALD (for males affected by the gene who do not yet have symptoms). The other condition caused by the faulty ABCD1 gene is called AMN, which affects nerves in the spinal cord and body.
In cerebral ALD the damage to myelin happens in the brain. When the myelin is damaged the nerves in the brain cannot work properly, and the person’s physical and mental abilities begin to deteriorate. Functions such as reasoning, speech and mobility are lost. Eventually, they become completely dependent.
In most males with ALD the adrenal glands are also affected. The adrenal glands make steroid hormones. Poor functioning of these glands is known as adrenal insufficiency. Symptoms include weakness, tiredness, vomiting and muscle pains. It is not possible to predict how the ALD gene will affect any one person: its effects can vary. Once diagnosis has been confirmed, the affected person needs to be closely monitored.
Issue Date: March 2015
Review Date: March 2017