Researchers at the University of Georgia have discovered a specific gene may play a major role in the development of a life-threatening birth defect called congenital diaphragmatic hernia, or CDH, which affects approximately one out of every 3,000 live births.
The hallmark of CDH is a rupture of the diaphragm that allows organs found in the lower abdomen, such as the liver, spleen and intestines, to push their way into the chest cavity. The invading organs crowd the limited space and can lead to abnormal lung development or poor lung function, which, depending on the severity of the condition, can cause disability or death.
In a paper published recently in the Journal of Clinical Investigation, UGA researchers, along with colleagues from the Rensselaer Polytechnic Institute and the University of California at San Diego, demonstrated for the first time that a gene known as Ndst1 plays a significant role in the proper development of the diaphragm, and abnormal expression of the gene could lead to CDH.
“Scientists really don’t know what causes CDH, so finding new clues like this is very important,” said Lianchun Wang, associate professor of biochemistry and molecular biology in the UGA Franklin College of Arts and Sciences. “Our laboratory tests with mice give us some good clues as to what causes this defect and what we might be able to do about it in the future.”
Like almost every other part of the body, the normal diaphragm is streaked with a complex network of veins, blood vessels and capillaries that carry critical nutrients to and from the tissue and ensure proper growth and function.
The researchers discovered that mice deficient in Ndst1 have a very poorly developed vascular system within the diaphragm, which contributes to the tissue’s weakness and tendency to tear under stress.
“With such a poorly developed vasculature, the cells that make up the diaphragm die at a much faster rate than normal because they do not get enough oxygen and other nutrients from the bloodstream,” said Wang, who is also a member of UGA’s Complex Carbohydrate Research Center. “This also means that new cells cannot regrow fast enough to make up for losses and the whole diaphragm becomes thin and fragile.”
Other organs in the Ndst1 deficient mice appeared completely normal, meaning that this gene is particularly associated with the development of the diaphragm.
Identifying the genes and genetic pathways involved in the development of CDH could lead to new diagnostic techniques and treatments, but Wang cautions that more work must be done before they are able to evaluate Ndst1′s role in humans.
Nevertheless, Wang and his colleagues are confident that these mouse experiments are a major step toward an understanding of a birth defect that has puzzled scientists for decades.
“This is only the beginning of our research on this subject,” he said. “We are moving ahead now with new experiments and tests that will tell us more about this important gene and how it contributes to human development.”