Motor neuron disease and toxic substances: Poss...( ANN ARBOR Mich. Motor neuron diseas...)

ANN ARBOR, Mich. Motor neuron disease is a rare, devastating illness in which nerve cells that carry brain signals to muscles gradually deteriorate. One form of it, Lou Gehrigs disease or ALS (amyotrophic lateral sclerosis), is familiar to the public in the lives of scientist Stephen Hawking and Morrie Schwartz, about whom Mitch Alboms Tuesdays with Morrie was written.

For most MND patients, the cause is unknown. Figuring out why these people develop the disease, which causes muscles to weaken, atrophy and cease to function, is an important step in developing therapies to treat or prevent motor neuron disease.

Now a team of University of Michigan scientists has gotten a step closer:

• They have discovered mutations in one key gene (neuropathy target esterase, or NTE) that cause a previously unknown type of inherited motor neuron disease.

• The discovery paves the way for better diagnosis and research on treatments.

• Most intriguing, the scientists found the mutations caused changes in a protein already known to be involved when people develop neurologic disorders as a result of exposure to toxic organophosphateschemicals commonly used in solvents and insecticides and also as nerve gas agents. This discovery points to a new lead in the search to understand MND.

We speculate there may be gene-environment interactions that cause some forms of motor neuron disease, says John K. Fink, M.D., professor of neurology at the U-M Medical School and senior author of the new study, which appears in the March issue of the American Journal of Human Genetics. He also is a researcher at the VA Ann Arbor Healthcare System.

Our findings support the possibility that toxic organophosphates contribute to motor neuron disease in genetically vulnerable people, says Fink. He believes the results suggest that altered activity of the gene found in patients in the study may also contribute to other motor ne
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