Adrenoleukodystrophy, or ALD, strikes one in 17,000 people. (In America, that’s one baby every 36 hours.) ALD is an x-linked metabolic disorder, therefore effecting boys and men most severely, and characterized by progressive neurologic deterioration due to demyelination of cerebral white matter. Brain function declines as the protective myelin sheath is gradually stripped from the brain’s nerves. Without that sheath, the neurons cannot conduct action potentials. In other words, the neurons cannot stop telling the muscles and other elements of the central nervous system what to do.
This sequence of events appears to be related to an abnormal accumulation of saturated very-long-chain fatty acids (VLCFA) in the serum and tissues of the central nervous system, which sets off an abnormal immune response that leads to demyelination. It is unclear exactly how this chain of events works, but scientists do know that it has its roots in genetics.
ALD is caused by a genetic abnormality, commonly referred to as a “genetic mutation”, affecting the X chromosome, otherwise known as an “x-linked” condition. Everyone has two sex chromosomes: women have two X chromosomes and men have an X and a Y chromosome. If a woman inherits the abnormal X chromosome, she still has a normal, second X chromosome to help balance out the affects of the mutation. Boys and men do not have a second X chromosome, so if they inherit this genetic abnormality, they will most likely get the disease.
ALD takes several forms, which can vary widely in their severity and progression. They include:
Childhood Cerebral Demyelinating ALD. This is the most common form of ALD, representing about 45% of all ALD cases. It is characterized by an inflammatory process that destroys the myelin, causing relentless progressive deterioration to a vegetative state or death, usually within five years.
There is no cure for ALD. But there are successful treatments