TDK conference 2017

Routine use of various veterinary medicines in some breeds of dogs may result in higher risk. Based on international and national literature data, it can be observed that the use of certain groups of active substances at therapeutic doses may cause severe symptoms in these individuals. The drug susceptibility of the affected breeds can be traced back to the 4-bp mutation of the multi drug resistance (MDR1) gene.

The aim of our work was to investigate the occurrence of the MDR1 gene mutation in the German shepherd dogs in Hungary, because according to the scientific literature the allele frequency of this abnormality in this dog breed is 6%. MDR1 gene encodes a funkcional protein, which plays important role in protecting biological barriers. It is expressed in high concentration in brain capillary endothelial cells, preventing the passage and accumulation of various toxic substances. If a deletion mutation of the MDR1 gene (ABCB1) occurs, a non-funkcional protein is produced, which is unable to protect the nerve tissue, and to prevent the accumulation of harmful substances such as macrocyclic lactones, antineoplastic agents or opioids. The hereditary mutation can be observed in collies, bobtails, Australian, English-and German shepherd dogs.

During the course of our study we collected blood samples from 54 German shepherd dogs (both-show line and work-line), 2 German shepherd mixed breed dogs and 6 Australian shepherd dogs; the owners gave signed, informed consent for study enrollment. The samples were taken from several different parts of Hungary for getting comprehensive and representative results. Genomic DNA was purified via spin column based method from all samples. ABCB1 mutation was determined by modified allele specific detection method via real-time PCR analysis. Two of the investigated Australian shepherd dogs were homozygous for the mutant ABCB1 allele, three dogs were carrying the mutation, and one animal was not affected by the disorder. German shepherd dogs and their mixed breeds were equally free of MDR1 mutation.

With respect to our results, we can state that the hereditary mutation does not affect the bloodlines of German shepherd imported to Hungary. In possession of this important information (both the owners and veterinarians), the veterinary drug therapy of the non-affected dogs would be considerably risk-free.