Scientists identify a new kind of genetic problem in muscular...( hat goes awry in this disorder thereby...)

While most people with FSHD have D4Z4 deletions, about 5 to 10 percent do not. These people may have mutations that affect the protein complex, Dr. Tupler says. Researchers have also identified people without FSHD who are missing the entire D4Z4 region and several nearby genes. This suggests that an abnormal D4Z4 region somehow creates havoc in muscle cells and/or that the nearby genes are necessary for development of the disease.

The findings also suggest that repetitive DNA sequences play a previously unsuspected role in human disease by influencing gene activity, Dr. Tupler says. About 40 percent of the human genome is comprised of these repetitive sequences, and they might play a role in several other human disorders. For example, certain variations in repetitive DNA sequences near the insulin gene in Type 1 diabetes have been linked to insulin levels and birth size. Other DNA repeats have been associated with bladder cancer. Studies of sequences like these could lead to a much better understanding of how gene activity is regulated, Dr. Tupler suggests.

Scientists can now focus on identifying which genes on chromosome 4 contribute to FSHD and how to regulate the gene activity, says Dr. Tupler. "Hopefully, other researchers will help with that," she adds.

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Contact: Natalie Frazin or Paul Girolami
301-496-5751
NIH/National Institute of Neurological Disorders and Stroke
8-Aug-2002