Addison’s Disease and Symmetrical Lupoid Onychodystrophy in Bearded Collies Provide Common Ground for Identifying Susceptibility Loci Underlying Canine Autoimmune Disorders

Posted on by Janet Boyd

Hypoadrenocorticism or Addison’s disease (AD) is a life-threatening condition that afflicts multiple dog breeds and results from autoimmune destruction of the adrenal glands. Similarly, another canine autoimmune condition that causes pain and suffering is Symmetrical Lupoid Onychodystrophy (SLO).

Both AD and SLO are postulated to be complexly inherited and preliminary data suggest a common set of susceptibility genes working in concert with additional genes that determine expression of either disease. For the study of AD and SLO the investigators will focus on the Bearded Collie breed due to its relatively high prevalence of both conditions and a genomic structure favorable for identifying variations in the DNA.

The investigators will scan the entire canine genome using genetic markers coupled with whole genome sequencing to identify chromosomal regions that harbor genetic changes contributing to disease manifestation. The disease risk conferred by each of these genetic variants, or quantitative trait loci (QTL), will then be calculated to develop a tool for selecting sires and dams early in life, thereby allowing breeders to choose mating pairs that will produce offspring with a low likelihood of developing AD and SLO.

Co-sponsored with the AKC Canine Health Foundation, Grant Number: 02488

RESEARCHERS

Anita Oberbauer, PhD; University of California, Davis
Amount: $15,000

Genetic Analysis of Hypoandrenocorticism in Nova Scotia Duck Tolling Retrievers

Posted on by PWDF Admin

Addison’s disease, also known as hypoadrenocorticism, is a deficiency of hormones that are produced by the adrenal glands and help regulate a dog’s metabolism, blood pressure, electrolyte balance and stress response. Though the disease is relatively uncommon in dogs, certain breeds—including Nova Scotia Duck Tolling Retrievers, Bearded Collies, Great Danes, Leonbergers, Portuguese Water Dogs, Standard Poodles and West Highland White Terriers—have a much higher risk than the general dog population.

Results

Researchers identified a region of the genome that is associated with the development of Addison’s disease in Nova Scotia duck tolling retrievers. Additionally, it appears that dogs that are homozygous (both chromosomes carrying the same genes) with respect to this region are at greater risk of developing Addison’s disease, even at a young age (under 2 years). Although additional genes are likely involved, this information is the first step toward understanding the genetics of this disease and developing a genetic test that will help eliminate Addison’s disease through informed breeding practices. This fellowship training grant also provided hands-on training for a veterinarian who is pursuing a research career.

Co-sponsored with the Morris Animal Foundation, Grant Number: D08CA-402

RESEARCHERS

Angela M. Hughes, DVM
University of California at Davis

Comparison of 2 ACTH Stimulation Tests in Determining Adrenal Function in Critically Ill Dogs

Posted on by PWDF Admin

Use of low-dose ACTH stimulation testing may be important in diagnosing mild degrees of adrenocortical insufficiency and a new syndrome, critical illness-related corticosteroid insufficiency (formerly known as relative adrenal insufficiency), which has been recognized in critically ill human and veterinary patients. Both 0.5 and 5 μg/kg doses of cosyntropin cause maximal adrenal stimulation with regard to serum cortisol concentrations in healthy dogs. The purpose of this study was to determine if low-dose ACTH stimulation testing was as accurate as standard-dose ACTH stimulation testing in determining adrenal function in critically ill dogs.

Results

Cosyntropin administered at a dose of 0.5 μg/kg IV appears to be at least as accurate as the administration of 5 μg/kg cosyntropin in determining adrenal function in critically ill dogs. In fact, the low-dose ACTH stimulation test may be more sensitive in detecting mild degrees of adrenal insufficiency in ill dogs.

Co-sponsored with the Morris Animal Foundation, Grant Number: D06CA-050

RESEARCHERS

Dr. Linda G. Martin, DVM, MS, DACVECC
Washington State University