This diploma thesis summarizes knowledge of significant genetically contitioned deseases occurring in border collies. There is described a total of 14 diseases, some with the location of causal mutation not yet known. Primary focus of this thesis is g.4411956_4411960delGTTT mutation of gene VPS13B causing Trapped Neuthrophil Syndrome (TNS), MDR1 gene's mutation AF045016.1: c.227_230delATAG associated with multidrug resistance (MDR1) and CUBN gene's mutation c.8392delC which causes intestinal malabsorption of cobalamin by another name ImerslundGräsbeck syndrome (IGS). A genotype analysis of 89 border collies with a proof of origin was performed. The DNA was extracted from buccal mucosal swabs, the isolation of DNA was performed by Chelex-100 from the native material. The analysis was proceeded by optimized PCR-RFLP method using restrictive MboI (MDR1) and Msl I (IGS) enzymes. There were detected 4 g.4411956_4411960delGTTT mutation vectors causing TNS. As for the MDR1 and IGS there wasn't detected any affected case.