Biochemical clues to muscular dystrophy.

Biochemical clues to muscular dystrophy

Israeli researchers have found two different forms of a protein whose appears to trigger Duchenne muscular dystrophy (DMD), a serious muscle-wasting disease that afflicts 1 in 3,500 male children. Their finding may help scientists explain why 30 percent of males with DMD suffer mental impairment.

The protein, called dystrophin, was identified in late 1987 by a Boston research team (SN: 1/2/88, p.4) led by Louis Kunkel of Harvard Medical School. It provided evidence that a lack of dystrophin starts a cascade of events leading to the characteristic muscle weakness of the disease. DMD is an inherited disease carried by women and passed down to sons. Affected males experience progressive muscle wasting and usually die in their 20s.

Uri Nudel and his colleagues at the Weizmann Institute of Science in Rehovot looked at normal rat tissue and found one kind of dystrophin in brain cells and another type of muscle cells. Their results, presented in a Jan. 5 letter to NATURE, suggest people with DMD who show mental retardation may have trouble producing the brain type of dystrophin, comments Donald S. Wood of the Muscular Dystrophy Association in New York City. While all boys with DMD lack muscle dystrophin, scientists theorize that a deficit of this protein in the brain may lead to retardation. Researchers have yet to learn dystrophin's exact role in the brain, Woods adds.

Ultimately, the new work may help researchers develop a treatment for the disorder. Any attempt to replace dystrophin would have to target both forms of the protein, Wood say.