Researchers identify defect that causes rare muscular d...( Subtle defects in the processing of a s...)

The scientists reported in two papers published in the July 25, 2002, issue of the journal Nature that defects in enzymes responsible for the processing of the structural protein dystroglycan are the underlying cause of several rare forms of muscular dystrophy that affect muscles and cause additional developmental brain abnormalities including mental retardation.

The new findings will immediately help doctors in providing accurate diagnosis and appropriate genetic counseling to patients and their families. In the longer term, knowing the underlying cause of the muscular dystrophies will help researchers tailor their interventions, according to Howard Hughes Medical Institute investigator Kevin Campbell. The disorder also disrupts an important component of learning and memory, so Campbell is hopeful that his teams studies will improve understanding of possible links between muscle physiology and neurobiology.

In the two articles, Campbell and his colleagues describe experiments that demonstrate that dystroglycan is defective in muscle-eye-brain disease and Fukuyama congenital muscular dystrophy. Separate genes had already been identified as defective in these syndromes, but researchers did not understand the underlying mechanism despite having information on the genes involved.

Campbell and his colleagues approached the problem by studying the large complex of proteins involved in several known muscular dystrophies. These proteins, called the dystrophin-glycoprotein complex, protect individual muscle cells from damage as they stretch and contract. They also help hold the cells in
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Contact: Jim Keeley
keeleyj@hhmi.org
301-215-8858
Howard Hughes Medical Institute
24-Jul-2002