Metachromatic leukodystrophy, also known as MLD, is a degeneration or change in the white matter of the central nervous system and brain. It is part of a family of genetic disorders called leukodystrophies that impair the way the myelin sheath grows or develops. With metachromatic leukodystrophy, there is an arylsulfatase A deficiency. Arylsulfatase A breaks down sulfatide; however, when it is not broken down, sulfatides build up to toxic levels and poison the nervous system, brain, kidney, and liver – making them deteriorate.
People can become affected with metachromatic leukodystrophy during three stages of their lives: adult, juvenile, and late infantile. If metachromatic leukodystrophy when the person is an adult, it will general appear after she is sixteen years old. The first symptoms for the adult onset form of MLD are personality changes, behavior changes, a decreased capacity to think or carry out daily functions, numbness of the hands and feet, and problems with the gait. It often is misdiagnosed as a psychiatric condition or a form of dementia. It has the slowest progression – where the decline can go on for decades – of any of the forms of MLD.
In the juvenile form of metachromatic leukodystrophy, the patient is affected between the ages of three and ten. They will typically begin perform poorly at school, show signs of dementia, and suffer from mental deterioration. Like the adult onset form of MLD, patients also have problems with their gait, behavior changes, and a decrease in intellectual capacity. In addition, they may suffer from seizures or muscle spasms. Although it progresses slower than the late infantile form, death can occur between ten and 20 years after the symptoms first appear.
The most progressive form of metachromatic leukodystrophy, late infantile MLD, is also the most common. Children are usually affected after they turn one year old; however, in many cases symptoms may not appear until they are four years old. Symptoms include the deterioration of muscles, overly rigid muscles, developmental delays, decrease in vision until the patient becomes blind, convulsions, paralysis, problems swallowing, and dementia. Unfortunately, children can fall into a coma and most do not live five to ten years beyond the time when the symptoms start.
Currently, there is not any treatment for metachromatic leukodystrophy. In some cases, the patient can receive a bone marrow transplant to slow the progression of the disease; however, it must be caught early to be a useful plan of action. Other steps can be taken to give the patient a better quality of life and treat the symptoms. These steps include medication to reduce symptoms and alleviate pain, surgery to relieve pain in the affect areas of the body, physical therapy, occupational therapy, speech therapy, recreational therapy, assistive devices, eye checkups, and gallstone treatment. Research is being conducted to learn more about the disease and how to treat it.