White matter and gray matter make up the different tissues in the brain, according to the ]]>University of Maryland Medical Center]]>. The ]]>National Institutes of Health (NIH)]]> notes that white matter contain nerve fibers, or axons; these are covered by ]]>myelin]]>, a protein and fatty substance that gives white matter its color. Myelin insulates the axon, allowing for a quicker transmission of electrical signals down a neuron. One rare disorder, leukoencephalopathy, has genetic mutations that results in a destruction of myelin, or “vanishing white matter.”
The ]]>US National Library of Medicine]]> states that the most common form of leukoencephalopathy with vanishing white matter has a childhood onset, meaning no symptoms present during infancy. Noticeable symptoms of leukoencephalopathy with vanishing white matter are motor symptoms, such as ataxia (problems coordinating movements) and spasticity (abnormal muscle stiffness); mental problems can also be present, though the US National Library of Medicine states this is not as severe as the motor symptoms). The ]]>United Leukodystrophy Foundation]]> adds that lethargy, fever, seizures and eye problems are also possible; in severe cases, coma and death can occur.
In milder forms, symptoms can begin during adolescents or adulthood, with behavioral symptoms appearing first. Women who have a mild for of leukoencephalopathy with vanishing white matter can have a variation known as ovarioleukodystrophy, where there is ovarian dysfunction, such as ovarian dysgenesis (abnormal development of the ovaries).