Genetic survey: Inherited blood disorder in Pomeranian dogs

This animal science honours projects will investigate the prevalence of CYB5R3 mutation associated with methaemoglobinemia in Pomeranian dogs.

Congenital methaemoglobinaemia (CM) is a rare disease in animals. In humans it is most commonly associated with deficiency of nicotinamide adenine dinucleotide-cytochrome b5 reductase (CYB5R3) deficiency, and depending on the exact genetic defect may be a relatively mild disease or may be very severe. 

We diagnosed a mild form of congenital methemoglobinemia in an adult Pomeranian dog. Genetic investigation showed that the dog was homozygous for a specific CYB5R3 mutation, indicating that it must have inherited identical defective gene alleles from both parents. 

The same genetic defect has been reported in a family of Pomeranian dogs in Japan, indicating that this could be an international problem in the breed. 

Our project aims to discover whether or not the defective gene is widespread in the Australian population of Pomeranian dogs. We will be recruiting Pomeranian dog breeders and owners to provide cheek swab samples for DNA analysis by PCR, sequencing and restriction enzyme analysis. 

At the end of this project, the data will enable estimation of how many individuals and which bloodlines of Australian Pomeranian dogs carry the CYB5R3 mutation. 

A DNA test will be available to determine mutation carrier status of dogs, and potentially enable elimination of the mutation through selective breeding. The phenotype of our index case was relatively mild, nonetheless it is a risk factor for serious complications under anaesthesia and its elimination will benefit the welfare of the dogs.

Anne Peaston

Supervisor

Dr Anne Peaston

Research area: Companion animal health

Recommended honours enrolment: Honours in Animal Science

Tagged in Honours projects - Animal science, Honours projects - Anne Peaston, Honours in Animal Science subtheme - Companion animal health