Leukodystrophy refers to progressive degeneration of the white matter of the brain due to imperfect growth or development of the myelin sheath, the fatty covering that acts as an insulator around nerve fiber. Myelin, which lends its color to the white matter of the brain, is a complex substance made up of at least ten different chemicals. The leukodystrophies are a group of disorders that are caused by genetic defects in how myelin produces or metabolizes these chemicals. Each of the leukodystrophies is the result of a defect in the gene that controls one of the chemicals. Specific leukodystrophies include metachromatic leukodystrophy, Krabbé disease, adrenoleukodystrophy, Pelizaeus-Merzbacher disease, Canavan disease, Childhood Ataxia with Central Nervous System Hypomyelination or CACH (also known as Vanishing White Matter Disease), Alexander disease, Refsum disease, and cerebrotendinous xanthomatosis.
In most cases, the diagnosis of a specific leukodystrophy is often not very easy. Typically the diagnosis will involve the input of a number of specialists, including neurologists, geneticists and metabolic physicians. Depending on the type of leukodystrophy, diagnostic methods may include a physical examination, blood tests, urine tests, MRI scans, nerve conduction tests, neuro-cognitive tests, nerve biopsy and genetic tests.
Treatment for most leukodystrophies is symptomatic and supportive and may include medications, physical, occupational, and speech therapies apart from nutritional, educational, and recreational programs. Bone marrow transplantation may also be part of the treatment of some types of leukodystrophies.
To ensure a timely and accurate diagnosis, the doctors will typically ask for the following procedures:
- Physical examination
- Blood tests
- Urine tests
- MRI scans: MRIs use radio waves and magnets. The energy from the radio waves creates patterns formed by different types of tissue and diseases. This produces detailed cross-sectional pictures that look like slices of the body.
- Nerve conduction tests:a test that measures the speed and degree of electrical activity in a nerve to determine if it is functioning normally.
- Neuro-cognitive tests: Helps determine the brain’s functions in certain parts
- Nerve biopsies: The doctors might order a biopsy to determine more accurate results
- Genetic test