Debilitating Pancreatic Disorder Linked to Cystic Fibrosis Gene
DURHAM, N.C. -- Researchers report finding a strong and surprising association between the gene that causes cystic fibrosis and a debilitating form of pancreatitis, inflammation of the pancreas.
Duke University Medical Center gastroenterologist Dr. Jonathan Cohn, who led the research team, said the main point of the study "is that many patients carrying a diagnosis of unexplained chronic pancreatitis have a disease where genetics plays a major and previously unsuspected role. This finding introduces a new concept about how chronic pancreatitis develops and it will change how physicians treat patients with this condition."
The researchers from Duke, the Durham VAMC and the University of North Carolina at Chapel Hill published the results of their study Thursday in the New England Journal of Medicine. The research was supported by grants from the National Institutes of Health, the Department of Veterans Affairs and the Cystic Fibrosis Foundation.
The most striking feature of chronic pancreatitis is severe, often incapacitating, abdominal pain. About two-thirds of the estimated 100,000 cases of chronic pancreatitis in the United States are caused by heavy alcohol use. However, chronic pancreatitis also strikes patients who are not drinkers, and in almost all these cases, the cause is unknown, or idiopathic.
The new study shows that in many patients with idiopathic chronic pancreatitis, there is a genetic explanation for their condition, the researchers said.
The gene involved in these cases of idiopathic pancreatitis is the same as the gene that causes cystic fibrosis. The classic features of cystic fibrosis include severe lung disease, abnormal sweat production and pancreatic insufficiency. The research team conducted extensive genetic analysis of 27 patients referred to Duke with idiopathic chronic pancreatitis. Of this group, 10, or 37 percent, showed abnormalities in the cystic fibrosis gene.
"These abnormalities were different from the genetic defects causing classic cystic fibrosis and this explains why the pancreatitis patients in this study didn't have the lung disease that is usually prominent in cystic fibrosis," said Dr. Lawrence Silverman, a University of North Carolina clinical molecular geneticist, who conducted the genetic analysis.
Silverman added that "these findings highlight how research on the gene causing one disease, cystic fibrosis, is helping explain a condition that originally seemed to have no connection to this disease."
The cystic fibrosis gene makes a protein that controls the movement of ions in and out of many types of cells. In the pancreas, this protein is concentrated in the epithelial cells lining the ducts. These ducts normally deliver digestive juices from the pancreas into the small intestine. It is thought, Cohn said, that the faulty cystic fibrosis gene causes these ducts to plug up, and that the pain felt by patients is due to the pancreas digesting itself.
While the genetic findings in this study provide clues about the early events leading to unexplained pancreatitis, these findings should also help doctors understand and treat patients with this condition, the researchers said.
One such patient is Frances Crouse, a 39-year-old mother of three from Elkin, N.C., who was first diagnosed with idiopathic chronic pancreatitis six years ago. After more than 20 hospitalizations and multiple operations for pancreatitis, she remains disabled by this condition.
"The pain is unbelievable -- there is no way to describe it," Crouse said. "When I first saw a doctor for the pain, it was very hard to convince him that I didn't drink alcohol. They went behind my back and talked to my family and friends and they ran all these tests because they thought I was lying. I understand their point of view, but it took years for them to figure it out."
According to Cohn, it is not unusual for situations like this to occur, especially when patients in extreme pain go to an emergency room and are examined by physicians unfamiliar with their condition.
"When patients with severe abdominal pain are examined, the specific findings in pancreatitis can lead physicians to underestimate the severity of their inflammation and pain," Cohn said. "To make matters worse, the blood tests used to diagnose acute pancreatitis are often insensitive in patients with chronic pancreatitis. Even though patients may be in great pain, these factors can prevent them from getting the treatment they need in a timely manner."