Mutation in a gene that codes for a protein involved in transporting materials within nerve cells causes muscle weakness and wasting, according to a report in the April issue of Nature Genetics. The findings could help hone in on the causes of related diseases.
If motor neurons - nerves cells along which the brain sends instructions to muscles - become damaged, muscles start to weaken and eventually stop working. By studying a family with individuals suffering from an inherited type of motor neuron disease that affects the vocal cords and muscles of the face, hands and feet, Imke Puls and colleagues at the National Institutes of Health, have identified the genetic cause of the disease. The scientists found a mutation in a gene that codes for a component of dynactin, part of the molecular "engine" that shunts materials, including nutrients required for proper functioning and survival of nerve cells, along "tracks" within the nerve cells. The mutation reduces the ability of dynactin to bind to these tracks - called microtubules - thereby disrupting transport within nerve cells and eventually causing the cells to degenerate.
Mutations in other proteins involved in transport within nerve cells may underlie other types of motor neuron disease.
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(C) Nature Genetics press release.
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