Adrenoleukodystrophy (ALD) is an inherited metabolic disorder. The affected gene in ALD is on the X chromosome, and it prevents the body from being able break down (metabolize) fatty acids. Boys have one X and one Y chromosome, and if the X chromosome carries the faulty gene, they will typically have severe disease. About one-tired of the boys with ALD will have cerebral ALD, the most severe form. Girls inherit an X chromosome from each parent. Girls with ALD usually have one faulty and one normal gene and often have milder disease and may not be diagnosed until adulthood.
The faulty gene involved in ALD prevents the body from being able to break down certain fatty acids. These fatty acids build up in the brain and spinal cord and keep nerve cells from sending signals throughout the body. As a result, those affected with ALD have problems with memory, learning, speaking, other mental functions and movement. Fatty acids may also build up in the adrenal glands and result in these glands not making enough hormones.
The primary non-transplant approach to ALD have been Lorenzo’s oil with special low fat diet, immune suppression and antioxidants agents. Those who start with this approach at an early age and are compliant have a decreased likelihood for developing childhood cerebral demyelination. However, those who develop cerebral manifestations by MRI and/ or clinical features, allogeneic transplant remains the only potentially effective long-term treatment. Children who receive a transplant early enough have the potential to have normal or near-normal mental and physical growth.
However, transplants for children who have already developed severe damage have disappointing results. The transplant cannot undo the damage that has already been done.