University of North Dakota Faculty/Staff Newsletter

Biochemist garners funding to continue study of congenital heart disease

The National Institutes of Health awarded Linglin Xie, Ph.D., a research assistant professor in the Department of Basic Sciences at the School of Medicine and Health Sciences, a $394,128 grant over the next three years for her molecular and genetic studyxie-linglin-hs of the proper development of the heart in the womb. The NIH's grant continues Xie's work on the poorly understood mechanisms underlying a common type of heart condition at birth, a congenital heart disease.

Xie's research is aimed at understanding why some kids are born with a "hole in the heart," clinically known as septal defects. Her group is specifically studying what causes atrial septal defect, in which there is an abnormal opening in the dividing wall between the upper filling chambers of the heart (the atria). As a group, atrial septal defects, ASDs, are detected in 1 child per 1,500 live births, and account for 30 to 40 percent of all congenital heart diseases.

"We specifically study a gene, Tbx5, whose mutation causes a disorder called Holt-Oram syndrome in humans," said Xie. "These patients are characterized by arm and hand malformation and heart defects, especially ASDs."

The hole in the dividing wall allows oxygen-rich blood from the upper left chamber of the heart to mix with oxygen-poor blood from the upper-right chamber, resulting in a much-reduced level of oxygen in the blood supplied to the body. Atrial septal defect may cause an enlarged right heart, heart failure, heart arrhythmia, stroke, pulmonary hypertension, or other conditions.

"My previous work at the University of Chicago found how the Tbx5 gene is a must in the formation of the atrial septum; however, many other factors are also needed in order for a normal septum to occur," she said. "We are now identifying what these other factors are and how they work together in forming a normal atrial septum."

A part of the U.S. Department of Health and Human Services, the NIH is the nation's medical research agency. The NIH is the largest source of funding for medical research in the world. The mission of the NIH is to seek fundamental knowledge about the nature and behavior of living systems and the application of that knowledge to enhance health, lengthen life, and reduce illness and disability.

For more information about Holt-Oram syndrome, see the NIH's National Center for Advancing Translational Sciences webpage at

-- Denis MacLeod, assistant director, Office of Alumni and Community Relations, UND School of Medicine and Health Sciences, 701. 777.2733,