Familial Robertsonian Translocation Involving Two Autosomes in Swiss Entlebucher Mountain Dogs

In domestic animals, chromosomal aberrations are well-documented causes of disorders that result in impaired fertility, malformations, and economic losses. The chromosomes of an alleged sub-fertile bitch of the Entlebucher mountain dog breed should be checked for such aberrations. Metaphase chromosomes were prepared from short-term lymphocyte cultures and microscopically analyzed for numeric or gross structural abnormalities using chromosome banding and chromosome painting probes. The analyses showed that the bitch was a carrier for a Robertsonian translocation involving chromosome 1 and a very small autosome, that could not be identified. The same aberration was detected in three related dogs including a rare case of homozygosity. Human carriers of Robertsonian translocations usually appear normal but seem to have a risk for offspring with genetic imbalances. Much less is known about the consequences of Robertsonian translocations in dogs. Nevertheless, it is of the utmost importance to identify dogs with chromosomal abnormalities and exclude them from breeding in order to prevent the transmission to the next generations. Therefore, the chromosomes of dogs with reproduction problems should always be checked for abnormalities in order to strengthen breeding programs and improve animal welfare.