TDK conference 2019

The ABCB1/P glycoprotein is the product of the ABCB1 gene ranged among the ABC superfamily. This protein mostly expressed on the apical surface of the epithelial cells, such as in the capillaries of the brain, the biliary cells, the small and large intestine, and the tubular cells of the kidneys. It functions like a transmembrane efflux pump that inhibits the accumulation of xenobiotics and toxins in the cells and tissues. This transport protein tends to gain growing importance both in veterinary and human medicine. Several frequently used drugs in veterinary medicine (ivermectin, loperamide, acepromazine, dexamethazone) are the substrates of the forementioned transport protein. A 4 base pair deletion mutation took place in the canine ABCB1 gene results in non-functional P-glycoprotein. Dogs with mutant allele may show unexpected clinical signs after being treated with certain pharmaceuticals. Serious outcome could happen if drugs accumulate in the central nervous system: ataxia, depression of the central nervous system, coma, or even death.

This type of drug sensitivity has already been described in several herding dog breeds, all of which can be traced back to a common British ancestor. The Shetland sheepdog falls within these affected breeds. In many European countries there were several surveys about the frequency of ABCB1 gene mutation among Shetland sheepdogs, yet we barely know the prevalence in Hungary.

Our primary aim was to unveil the prevalence of ABCB1 mutant allele in Shetland sheepdogs living in Hungary. Secondary we compared our results with studies from other European countries.

We have got in touch with three Shetland sheepdog breeders. Further aim of the research was to detect the inheritance of the mutant allele, therefore we surveyed the family relationships between the examined dogs.

We collected blood samples from 37 Shetland sheepdogs to isolate genomic DNS. The ABCB1 mutation was detected by allele-specific PCR. From the examined dogs 21 were heterozygous and 10 homozygous for the mutant ABCB1 allele.

The frequency of mutant allele in the examined Shetland sheepdogs has been 55,4%, which is much higher than in other European countries, where the prevalence was only 30%.