CHAPEL HILL, N.C. UNC researchers have discovered how the genetic defect underlying one of the most common congenital heart diseases keeps the critical organ from developing properly. According to the new research, mutations in a gene called SHP-2 distort the shape of cardiac muscle cells so they are unable to form a fully functioning heart.
The study also shows that treatment with a drug that regulates cell shape rescues the cardiac defect, pointing to therapeutic avenues that could one day benefit Noonan syndrome patients. The results, which were produced in a frog model of the disease, appeared online January 25, 2012, in the journal Development.
Genetic studies have shown that SHP-2 plays a critical role in human physiology and disease. Interestingly, different mutations in different portions of SHP-2 result in three different diseases Noonan syndrome, a severe congenital heart disease; juvenile myelo-monocytic leukemia, a lethal form of cancer; and Leopard syndrome, a rare condition with skin, facial and cardiac abnormalities. This observation has intrigued a number of researchers, including senior study author Frank Conlon, PhD.
"I've wondered how it is that one mutation gives heart disease and doesn't affect your white blood cells, and another will wipe out your white blood cells and leave your heart alone," said Conlon, an associate professor of genetics and a member of the UNC McAllister Heart Institute. He and others have explored this mystery by creating transgenic animals -- fruit flies, mice, or in Conlon's case, frogs -- that possess a mutated form of SHP-2.
When Conlon and his team genetically engineered frogs to contain the very same defects seen in humans with Noonan syndrome, they found that the frogs did in fact develop cardiac defects. But when they created them with a mutation seen in humans with leukemia, there were no heart defects. The researchers then performed 3D modeling on the animal
|Contact: Les Lang|
University of North Carolina School of Medicine