Microsatellite Marker C04107 as a Diagnostic Marker for Copper Toxicosis in the Danish Population of Bedlington Terriers

Abstract

The linkage phase of marker C04107 was evaluated before implementation of the marker in a diagnostic test. Blood samples from 68 dogs were collected and genotyped by PCR. Two alleles were detected with sizes of 160 bp and 164 bp and allele frequencies of 0.45 and 0.55 respectively. Genotyping revealed that 35 dogs were heterozygous (51.5%), 22 dogs were homozygous for the normal allele (32.3%) and 11 dogs were homozygous for the disease allele (16.2%). Liver biopsies were taken from 14 selected dogs and the copper content was evaluated histologically. Biopsies from 8 dogs homozygous for the disease allele showed many copper granules along with single cell necrosis, haemosiderosis and cellular infiltration. In liver biopsies from 6 dogs genotyped to be heterozygous or homozygous for the normal allele, copper granules were absent or moderate in number and no lesions were present. The survey demonstrates that the linkage phase of marker C04107 in the Danish population of Bedlington terriers is similar to the linkage phase detected in other countries. Thus, the marker can be used in a diagnostic test for copper toxicosis in Denmark.

Sammendrag

Koblingsfasen af markør C04107 blev evalueret forud for implementering af markøren i en diagnostisk test i Danmark. Blodprøver fra 68 hunde blev indsamlet og genotypet ved hjælp af PCR. Ved genotypningen fremkom to alleler med størrelser på henholdsvis 160bp og 164bp samt allelfrekvenser på henholdsvis 0.45 og 0.55. Genotypningen viste, at 35 hunde var heterozygote (51.5%), 22 hunde var homozygote for den raske allel (32.3%), og 11 hunde var homozygote for den defekte allel (16.2%). Leverbiopsier blev udtaget fra 14 udvalgte hunde, og kobberindholdet vurderet histologisk. I biopsier fra 8 hunde, der var homozygote for den defekte allel, sås mange kobberholdige granula, nekrose af enkelte celler, hæmosiderose og infiltration med inflammationsceller. I leverbiopsier fra 6 hunde, der var heterozygote eller homozygote for den raske allel, sås et varierende antal af kobbergranula fra ingen til et moderat antal og ingen læsioner. Undersøgelsen demonstrerer, at koblingsfasen mellem markør C04107 og sygdomsgenet er den samme i den danske Bedlington terrier population som i de øvrige undersøgte populationer i USA og Europa. Markøren er derfor anvendelig i en diagnostisk test for kobertoxicose i Danmark.