Adrenoleukodystrophy

What is Adrenoleukodystrophy?

Adrenoleukodystrophy (ALD) is one of a group of genetic disorders called the leukodystrophies that cause damage to the myelin sheath, an insulating membrane that surrounds nerve cells in the brain. People with ALD accumulate high levels of saturated, very long chain fatty acids (VLCFA) in the brain and adrenal cortex because they do not produce the enzyme that breaks down these fatty acids in the normal manner. The loss of myelin and the progressive dysfunction of the adrenal gland are the primary characteristics of ALD. ALD has two subtypes. The most common is the X-linked form (X-ALD), which involves an abnormal gene located on the X-chromosome. Women have two X-chromosomes and are the carriers of the disease, but since men only have one X-chromosome and lack the protective effect of the extra X-chromosome, they are more severely affected. Onset of X-ALD can occur in childhood or in adulthood. The childhood form is the most severe, with onset between ages 4 and 10. The most common symptoms are usually behavioural changes such as abnormal withdrawal or aggression, poor memory, and poor school performance. Other symptoms include visual loss, learning disabilities, seizures, poorly articulated speech, difficulty swallowing, deafness, disturbances of gait and coordination, fatigue, intermittent vomiting, increased skin pigmentation, and progressive dementia. In the milder adult-onset form, which typically begins between ages 21 and 35, symptoms may include progressive stiffness, weakness or paralysis of the lower limbs, and ataxia. Although adult-onset ALD progresses more slowly than the classic childhood form, it can also result in deterioration of brain function. The abnormal genes that cause neonatal ALD are not located on the X-chromosome, which means that both male and female babies can be affected. Symptoms include mental retardation, facial abnormalities, seizures, retinal degeneration, weak muscle tone, enlarged liver, and adrenal dysfunction. This form usually progresses rapidly. A mild form of ALD is occasionally seen in women who are carriers of the disorder. Symptoms include progressive stiffness, weakness or paralysis of the lower limbs, ataxia, excessive muscle tone, mild peripheral neuropathy, and urinary problems.

Is there any treatment?

What is the prognosis?