Scientists unravel complicated genetic disease in one ...( Scientists consider themselves lucky wh...)

Now, for what is believed to be the first time, scientists have unraveled the complicated genetics of an inherited intestinal disease, opening the door to revealing complete genetic pictures of other complex diseases. Their results provide stirring reminders that it's important to consider all parts of a gene, not just those carry instructions for a protein, when looking for contributors to disease.

In the current advance online edition of Nature Genetics, the scientists report that three regions -- parts of chromosomes 3, 10 and 19 -- are crucial for causing Hirschsprung disease and together explain its complicated inheritance pattern. Looking for changes within those regions, the scientists discovered that, more often than not, the protein-encoding parts were unchanged.

"Just because coding sequences aren't changed doesn't mean a gene isn't involved," says Aravinda Chakravarti, Ph.D., director of the McKusick-Nathans Institute of Genetic Medicine at Johns Hopkins and whose laboratory (while at Case Western Reserve University in Cleveland) led the U.S. effort. "Many diseases likely have genetics similar to Hirschsprung disease, and we've shown that such complex genetic contributors can be discovered with a carefully designed study."

Hirschsprung disease, in which nerves are missing that normally control the bowel, occurs in about one in 5,000 births. Because the way the disease pops up in family trees is complex, researchers collected and analyzed samples from parents and children in 49 families, each with at least two affected siblings.

The scientists found that three crucial regions explain the inheritance of the "short-segment" form of H
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Contact: Joanna Downer
jdowner1@jhmi.edu
410-614-5105
Johns Hopkins Medical Institutions
14-Apr-2002