Exocrine Pancreatic Insufficiency May Have Complex Inheritance Pattern

Researchers studying exocrine pancreatic insufficiency (EPI), a disease in which food is not properly digested and absorbed, believe that the condition may have a complex mode of inheritance. Prevalent in German Shepherd Dogs, Rough-Coated Collies and Chow Chows, EPI affects more than 100 breeds.

Leigh Anne Clark, Ph.D., assistant professor of genetics and biochemistry at Clemson University, is studying the genetic variations between 100 healthy German Shepherd Dogs and 100 EPI-affected German Shepherd Dogs. "EPI may result from mutations in multiple genes or from both genetic and environmental factors," she says. "If we can identify the gene or major gene causative for EPI, we will be able to develop a genetic test. Breeders could then determine which dogs are at risk for developing EPI."

EPI is a disorder in which the pancreas fails to produce an adequate amount of digestive enzymes. Without those enzymes, food is not properly digested and absorbed. No matter how much food is ingested, a dog with EPI can literally starve to death.

Signs of EPI include weight loss, ravenous appetite, diarrhea, eating feces, vomiting, gas, changes in temperament, and loose, foul-smelling stool. The disease can strike at any age, but signs many not appear until as much as 90 percent of the pancreas is destroyed.

The most common cause of EPI in dogs is pancreatic acinar atrophy (PAA) in which the acinar cells in pancreatic tissue decrease in number and function. Acinar cells produce enzymes that help digest carbohydrates, fats and proteins. These enzymes help break down food into smaller parts so nutrients can be absorbed through the intestinal wall. Though little is known about the cause of PAA, researchers believe the condition is genetically inherited.

EPI can also develop due to chronic pancreatitis, or inflammation of the pancreas. The pancreas synthesizes all the major digestive enzymes, but repeated bouts of pancreatitis can destroy acinar cells that synthesize these enzymes. In rare cases, EPI results from pancreatic cancer or pancreatic hypoplasia, a congenital condition in which the exocrine pancreas does not fully develop.

Though EPI cannot be cured, it can be managed with a good prognosis. Pancreatic enzyme supplements can be given to replace the naturally occurring digestive enzymes depleted by EPI. Most EPI dogs also require diet modification, including reducing fiber or grain.

Until a genetic test is developed, breeders are advised to not breed dogs with EPI or to repeat matings that produced affected dogs. To learn more about EPI, you may visit www.epi4dogs.com, a Web site begun by the owner of a Spanish Water Dog affected by the condition. The site offers comprehensive information about the disease and includes before- and after-treatment photo­graphs, the latest research findings and a list of affected breeds.