The term Leukodystrophy refers to a group of genetic disorders that are characterised by the imperfect growth, development or maintenance of the white matter which is known as myelin. Myelin is the insulation material that is made from proteins and lipids ( fats etc) that is produced in the neuron to coat and protect the transmission arm of the neuron – the axon.This process is called Myelination. Myelin is produced for the central nervous system in cells called an Oligodendrocytes and for the peripheral nervous system the same function is performed by the Schwann cells. The receiving arm of the neuron is called a dendrite and is not myelinated.
Myelin is a spongy substance which is white in appearance and those axons which are myelinated are referred to as ” the white matter” of the brain.
The major purpose of the myelin is to increase the speed of transmission of an impulse ( message) to the next neuron and also to prevent the electrical current from escaping. An impulse or message from one cell to another is an electro – chemical process.
When this process is disrupted or destroyed by a dysfunctional metabolic process, with a genetic cause and has a progressive clinical course it can be classified as a Leukodystrophy.
Leukodystrophies, as stated, are characterised by the imperfect growth, development or maintenance of the white matter which is known as myelin. Terms often used with the various different Leukodystrophies include the following:
Demyelination: The destruction, removal or loss of the myelin sheath on a nerve or nerves.
Hypomyelination: The defective formation of myelin in the spinal cord, brain or peripheral nervous system.
Dysmyelination: The improper laying down or breakdown of a myelin sheath of a nerve fibre caused by abnormal myelin metabolism.
The term Leukoencephalopathy refers to any of a group of diseases or disorder that affects the white matter of the brain.