Copper Killer.

Copper toxicosis: A common autosomal recessive disorder found in Bedlington Terriers, which causes the retention of copper in the liver leading to chronic active hepatitis and ultimately death. The symptoms include weight loss, vomiting, anorexia, ascites, jaundice and abdominal pain.

Copper is a very important mineral found in trace amounts within the mammalian body. It is incorporated into enzymes which catalyse important reactions. It is mainly stored in the liver but can be found in muscle, spleen and brain tissue. The ingested copper is absorbed in the blood via the mucosa of the small intestine. In dogs it is then transported to the liver via gamma globulins in the blood. Then in normal dogs it is excreted as bile salts in the faeces. However sufferers have a genetic defect in the hepatic lysosomal mechanism for this normal excretion, thus causing a build of copper in the liver.

Studies have isolated the gene COMMD1 responsible for the disorder. The mutated form occurs from a deletion in exon 2 near to microsatellite C04107. However, some Bedlingtons suffering from copper toxicosis have been found not to have the homozygous form of the detrimental gene. This evidence shows a second unknown gene may also be responsible.

Copper toxicosis affects other breeds such as Westies, Dobermans and Dalmatians, but is not strangely associated with the COMMD1 gene. The human equivalent is called Wilson’s disease proving how animal studies can help human medicine.

References:
1) O.P. Forman, M.E.E. Boursnel, B.J. Dunmore, N. Stednall, B. van de Sluis, N. Fretwell, C. Jones, C. Wijmenga, J. Rothuizen, B.A. van Oost, N.G. Holmes, M.M. Binns and P. Jones. Characterization of the COMMD1 (MURR1) mutation causing copper toxicosis in Bedlington terriers. Animal Genetics (36) Issue 6 p497, (Dec 2005)

2) S. Haywood. Copper toxicosis in Bedlington Terriers. The Veterinary Record (159) p687 (2006).

3)B. van de Sluis, J. Rothuizen, P. L. Pearson, B. A. van Oost and C. Wijmenga. Identification of a new copper metabolism gene by positional cloning in a purebred dog population. Human Molecular Genetics (11) No. 2 pp165-173 (2002)

Links:
1) http://www.blackwell-synergy.com/doi/abs/10.1111/j.1365-2052.2005.01360.x
2) http://veterinaryrecord.bvapublications.com/cgi/content/full/159/20/687-a?view=long&pmid=17099181
3) http://hmg.oxfordjournals.org/cgi/content/full/11/2/165
4) http://www.auntjeni.com/copper.htm

Posted By: James Osman
Student No: 41236530