While people and dogs are generally resistant to Mycobacterium avium infections, there are certain individuals that lack proper host defense against these intracellular organisms. The precise molecular basis is still unknown, but there is much interest because of the major morbidity and mortality in susceptible patients. We have recognized that many young adult Miniature Schnauzers (and few Basset Hounds) succumb to systemic avian tuberculosis (referred to mycobacterium avium complex or MAC), characterized by lymphadenopathy, fever, diarrhea and respiratory signs. Based upon our pedigree analysis, this appears to be a simple autosomal recessive trait. Our preliminary pedigree and limited molecular genetic data suggest a strong signal for one specific small chromosomal region. We will substantiate this data with further samples and investigations and also include whole genome sequencing to identify the precise cause.

Identification of the molecular basis of this genetic predisposition will allow for a better understanding of the disease and the development of a DNA screening test to identify animals at risk of disease as well as carriers, thereby reducing the production of dogs predisposed to this fatal disease in future generations. As avian tuberculosis is a zoonotic disease, our findings should provide insight into genetic determinants of host microbe interaction and resistance in dogs and people, thereby could have an impact on comparative medicine.

Funding for the research is provided through the efforts and generosity of the American Miniature Schnauzer Club. The AKC Canine Health Foundation supports the funding of this effort and will oversee administration of funds and scientific progress reports.

Watch Dr. Giger Discuss his work in this CHF-sponsored VetVine Video.