Leukodystrophy is a rare inherited gene mutation disorder within the myelin sheath creation process. It is passed down from parent to child. The inherited genes may be recessive or dominant depending on the type of leukyodystrophy the patient has been diagnosed with. Leukodystrophy is mostly an inherited disorder, which as stated earlier is passed on from parent to child. Though, most cases present in children under the age of five, other forms of the disorder may appear later in life. The forms of the disorder occurring later in life are still caused by a mutation of a specific gene, but the mutation is not inherited. Leukodystrophy is a progressive disorder and the patient’s prognosis tends to get worse throughout their life. Those with the inherited form of the disorder will have a terminal diagnosis.
For us to be able to understand Leukodystrophy, you will need to know some facts about the human nervous system. The human nervous system has two main segments: the central nervous system and the peripheral nervous system. With the communication of these two systems our entire body is able to function properly.
The human central nervous system contains the brain, the spinal cord, and billions of specifically designed cells called neurons. Neurons have the important job of transmitting signals throughout the body to tell it what to do. The peripheral nervous system houses the rest of the neurons in your body that have the responsibility of detecting sensory stimuli. In turn a signal is sent to the central nervous system of their existence. At this time they communicate with the motor neurons that connect the central nervous system to the muscles and follow the instructions of those signals for muscle movement.
The protective covering around the nerves is known as myelin; also known as white matter because of its white appearance. Myelin is composed of several different fatty molecules and proteins. Myelin’s job is to insulate the nerves as well as to protect them, similar to the covering on electrical wiring. It also has another function and which is to allow rapid and proper communication of signals between neurons. With myelin, your neurons can transmit signals as fast as sixty meters per second. If this protective coating is damaged it can greatly reduce the speed of the signals or cause your nervous system to malfunction.
Leukodystrophy is the result of a malfunctioning or growth issue of the myelin sheath. Many genes and proteins are required to form the myelin. When the normal creation process or growth is disrupted due to a mutated gene the result is leukodystrophy.
Leukodystrophy has a few common relations to another disease which also attacks the myelin sheath, multiple sclerosis. Leukodystrophy and multiple sclerosis are both generated by the loss of myelin from the axons. However, the causes are very different because, leukodystrophy is caused by a mutation in one of the genes responsible for the growth of the myelin; multiple sclerosis is caused by the patient’s immune system attacking the myelin sheath.
Leukodystrophy has over forty different variations that include metachromatic leukodystrophy, Krabbé disease, adrenoleukodystrophy, Pelizaeus-Merzbacher disease, Canavan disease, Childhood Ataxia with Central Nervous System Hypomyelination Alexander disease, Refsum disease, and cerebrotendinous xanthomatosis.
One of the most noticeable symptoms of leukodystrophy disease is a very gradual noticeable decline in the development process of an infant or child whom has previously appeared well. As leukodystrophy’s disease process progresses, distinct losses appear in the patient’s muscle functions, actions, bearing, and speech. The patient’s ability to eat, vision, hearing, and their behavior are also affected. Parents will often note a slowdown in mental and physical development milestones of the patient. Signs and symptoms vary greatly among the types of leukodystrophies, and may be difficult for physicians to recognize leukodystrophy in its early stages.
Treatment of the leukodystrophies is dependent upon the patient’s symptoms. Though the types of leukodystrophy vary most of the treatments available are supportive; such as medications, physical, occupational, and speech therapies. There has also been success utilizing bone marrow transplantation for several of the types of leukodystrophies. This treatment is still under investigation to see if it slows down the degeneration of the myelin sheath, or if it halts the progression of the disease. Time will tell what the long term benefits will be for the patient.
References:
United Leukodystrophy Foundation
The National Institute of Neurological Disorders and Stroke
