MSA: SOME ANSWERS
Lawrence I. Golbe, MD
Professor of Neurology, Rutgers Robert Wood Johnson Medical School Director of Clinical Affairs and Scientific Advisory Board Chairman, CurePSP
What is multiple system atrophy( MSA)?
Multiple system atrophy is a disease of the brain and spinal cord. It is often classified as one of the“ parkinsonian” conditions because it often resembles Parkinson’ s disease, at least for the first few years. The resemblance is in the general slowness, stiffness, and balance loss. But MSA usually has at least two other important categories of symptoms to some degree. One is impairment of the cerebellum, producing a coarse tremor, drunken-appearing walk, and slurred speech. The other is impairment of the autonomic nervous system, which maintains such things as blood pressure, sleep, bowel action, and bladder emptying. The result can be fainting, insomnia, constipation, and urinary urgency or incontinence. Many other less common symptoms can occur, too.
How common is MSA?
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MSA is rare, with about 13,000 sufferers in the United States, most of whom have not yet received a correct diagnosis. This compares with about 20,000 with progressive supranuclear palsy( PSP), which is a similar condition; about 700,000 with Parkinson’ s disease; and 5.8 million with Alzheimer’ s disease. New cases of MSA arise in about six people per million per year. This means that in the U. S., about five people are newly diagnosed with MSA each day.
Are there different types of MSA?
There are three types that grade into one another. MSA emphasizing slowness and stiffness was once called striatonigral degeneration. MSA emphasizing autonomic problems was called Shy-Drager syndrome. Cases emphasizing cerebellar problems were called sporadic olivopontocerebellar atrophy. These terms were discarded in 1989, when all three were found to be variants of the one disease, which then received its current name. What all three variations have in common is a type of protein that forms clumps in the same types of cells. The differences among the three types of MSA are dictated by which parts of the brain or spinal cord are most involved.
What is the cause of MSA?
The ultimate cause( called the etiology of the disease) is not known. MSA almost never occurs twice in a family, and there are no confirmed clusters related to occupation, industry, diet, ethnicity, or geography. A variant in a gene called alpha-synuclein( SNCA) occurs more often in people with MSA than in the rest of the population, but this accounts for only a small fraction of the overall cause of the disease. Various chemical toxins have also been implicated, but these results have not been confirmed in multiple studies.
What’ s going wrong in the brain and spinal cord cells?
The direct cause of the loss of brain and spinal cord cells( the pathogenesis of the disease) in people with MSA is not fully understood. However, it has to do with the clumps of alpha-synuclein protein mentioned above. Alpha-synuclein is a normal protein that is necessary for brain cells to signal to one another. The current favored theory is that too much alpha-synuclein is made. Once it reaches a certain concentration in the cell, it starts to stick together. The resulting blobs, when they are still too small to be seen with a microscope, are toxic.