5/18/09 Investigation of Gallbladder Disease and Hypercholesterolemia in Shetland Sheepdogs

March 2008, Updated December, 2008* and May 2009
Background: Gallbladder disease has been recognized with increasing frequency in dogs within the past decade1-3. Whether or not this is the result of a true increase in disease prevalence or simply the result of increased detection is not definitive. However, some suggest that incorporation of abdominal ultrasonography in dogs as a routine diagnostic tool has resulted in increased detection of gallbladder disease2. Several recent articles describing gallbladder mucoceles (severe distention of the gallbladder caused by a thick mass of sludge and mucus) in dogs suggest a breed predilection for the problem in Shetland Sheepdogs as well as Cocker Spaniels and Miniature Schnauzers. Both Shetland Sheepdogs and Miniature Schnauzers are breeds predisposed to hyperlipidemia (too much lipid or fat in the blood),4,5 a factor that is known to contribute to gallbladder disease in people6,7. A recent study confirms a link between hyperlipidemia and hypercholesterolemia (high blood cholesterol levels) and gallbladder mucocele formation in Shetland Sheepdogs2. Collectively, this suggests the possibility of a genetic defect in a protein responsible for lipid homeostasis (regulation of blood lipid levels). The Veterinary Clinical Pharmacology Laboratory at Washington State University is currently investigating a gene that plays an important role in lipid homeostasis. A defect in this gene could be the cause of gallbladder disease in Shetland Sheepdogs.
Participation: The Veterinary Clinical Pharmacology Laboratory is seeking DNA (cheek swab samples) from Shetland Sheepdogs that have any of the following:
Hypercholesterolemia (fasting serum or plasma cholesterol > 400 mg/dL)
Hypertriglyceridemia (fasting serum or plasma triglycerides > 600 mg/dL)
Hyperbilirubinemia while not anemic (serum or plasma bilirubin > 2.0 mg/dL)
Surgical or ultrasonographic report of gallbladder disease (documentation must be made by DVM).
As of December, 2008, the study is limited to dogs that have had surgically confirmed gallbladder
mucoceles.

May, 2009 DNA from normal older Shelties needed!!!!

Participation for new phase of study:
Dr. Katrina Mealey, primary investigator of the study, has identified a few abnormalities in genes that may be responsible for causing gallbladder disease/hyperlipidemia in Shetland Sheepdogs. To confirm that these abnormalities are truly associated with the disease, and not just a breed-related gene polymorphism, she needs to assess DNA from Shetland Sheepdogs unaffected by gallbladder disease or hyperlipidemia. Because gallbladder mucoceles tend to occur in older dogs (median age 9 years), DNA from unaffected Shelties 9 years of age or older is needed.
Participation - The Veterinary Clinical Pharmacology Laboratory is seeking DNA (cheek swab samples) from Shetland Sheepdogs meeting the following criteria:
• 9 years of age or older
• Healthy, i.e. good appetite and good activity level
• Recent blood tests that are normal (CBC and chemistry panel)
Participation is voluntary (i.e., you will not receive payment for the sample nor will you be charged for having your dog’s DNA tested).
DNA swabs can be obtained by emailing Dr. Katrina Mealey at the address listed below.
Instructions for correctly obtaining a sample can be found at the following website:
http://www.vetmed.wsu.edu/depts-VCPL/instructions.aspx
Questions about an individual animal’s inclusion in this project can be addressed to:
Katrina Mealey DVM PhD; Diplomate, ACVIM; Diplomate, ACVCP
Associate Professor and Director, Veterinary Clinical Pharmacology Laboratory
College of Veterinary Medicine
Washington State University
Pullman WA, 99164-6610
EMAIL: kmealey@vetmed.wsu.edu

*UPDATE! As of December, 2008, Dr. Mealey has received samples and medical information from 21 Shelties, 10 of which had confirmed mucoceles. Her group will now concentrate on Shelties with mucoceles. They have finished processing samples for 90% of the gene and will continue to work on the final 10%. They are also comparing the genes of affected and unaffected dogs. Dr. Mealey said, “I was surprised (in a positive way) on the response!…… Thanks for your assistance--for an uncommon disease we were able to collect a good number of samples with complete medical information in a short time period (especially considering this was breed specific!)”. Thanks to everyone who has participated. Continued participation is essential to the success of this study!
Mary Mahaffey DVM [mbmahaffey@bellsouth.net]