WEDNESDAY, July 24, 2002 (HealthDayNews) -- University of Iowa researchers have found a molecular mechanism that appears to be responsible for brain defects in people with some forms of muscular dystrophy.
This subset of muscular dystrophies includes Fukuyama Congenital Muscular Dystrophy, Walker-Warburg Syndrome (WWS) and Muscle-Eye-Brain (MEB) disease. These muscular dystrophies not only weaken and destroy muscles, they also cause brain abnormalities that result in severe mental retardation.
Many genetic mutations that cause muscular dystrophy affect protein components of what is called the dystrophin-glycoprotein complex. It's a large complex of proteins that provides a vital bridge linking structures inside and outside of cells, and seems crucial for muscle physical integrity.
In two studies in tomorrow's issue of Nature, the researchers found a key player in this subset of muscular dystrophies is a protein called dystroglycan, which is found in the dystrophin-glycoprotein complex. There's no actual defect in the dystroglycan protein.
The problem is a genetic defect in enzymes responsible for adding sugar residues to the dystroglycan protein. That means that certain sugars aren't added to the protein.
One study used antibody probes that analyze dystroglycan. It found people with Fukuyama and MEB disease do have dystroglycan protein in their muscles. However, it doesn't have all the normal sugar attachments.
The study also found this sugar attachment shortfall means dystroglycan can't interact with its normal biological partners at the surface of cells in muscles and the brain.
The other study involved mice bred to lack dystroglycan in their brains. These mice had severe brain defects that resembled those found in people with Fukuyama, WWS and MEB.
More information
The National Institute of Neurological Disorders and Stroke has more on the treatment and prognosis for muscular dystrophy
