Inherited copper toxicosis in the Bedlington terrier: a report of two clinical cases

The clinical signs, laboratory findings and pathological changes are described in two cases of inherited copper toxicosis in the Bedlington terrier. The first case presented with acute signs of depression, vomiting, anorexia, weight loss and jaundice while the second case followed a more chronic course with less severe clinical signs which included weight loss and ascites. Both dogs had elevated circulating levels of alanine aminotransferase (ALT), however other haematological and biochemical parameters, while reflecting liver involvement, varied between the two cases. Chemical analysis of the liver revealed elevated copper levels in both cases (951·7 and 1093·4 μg/g wet weight respectively; normal less than 150 μg/g). These levels, however, are less than some affected but asymptomatic Bedlington terriers. Pathologically the first case had micronodular cirrhosis, while the second had focal hepatitis with fibrosis. Both dogs showed vacuolation of the white matter in the cerebrum, cerebellum, midbrain and medulla. Attention is drawn to the similarities and differences between copper toxicosis in the Bedlington terrier and Wilson's disease in man.     

Copper toxicosis in Bedlington Terriers in the United Kingdom

This paper summarizes the clinical and laboratory data on two adult Bedlington Terriers with liver disease associated with copper toxicosis. The younger dog, at 3 years, had elevated serum levels of alanine aminotransferase and alkaline phosphatase with active parenchymal cell degeneration and hepatitis. The second dog developed chronic hepatic failure at 5 years with advanced cirrhosis. Both dogs had stainable copper granules in the liver and chemical analysis of their livers revealed elevated copper contents (1,027 and 10,728 μg/g dry weight; normal less than 300 μg/g). These are the first published cases of this inherited abnormality of copper metabolism in this breed in this country.     

Copper Toxicosis in Bedlington Terriers

Copper toxicosis of Bedlington Terriers (Chronic progressive hepatitis) is a genetically transmitted disease. The typical feature of this disease is accumulation of copper in the liver tissue. The changes vary from mild hepatitis to chronic progressive hepatitis and cirrhosis.The material of this study consists of 2 cases of copper toxicosis examined at the Department of Pathology in Helsinki in the years 1980–82. Moreover a re-examination of tissue samples was made of all Bedlington Terriers examined during the years 1969–1982 at the same department. Six of the 14 examined dogs showed a positive reaction for copper in their liver tissues. The possible relationship of the examined dogs is not yet known.     

Copper-associated liver disease in Dalmatians: a review of 10 dogs (1998-2001)

This retrospective study summarizes 10 Dalmatians suspected of having hepatic copper toxicosis. Hepatic copper toxicosis can result from either a primary metabolic defect in hepatic copper metabolism or from altered hepatic biliary excretion of copper. An inherited copper-associated hepatopathy has been documented in Bedlington Terriers, and there is evidence for familial copper-associated liver disease in West Highland White (WHW) Terriers and Skye Terriers. Nine of the 10 Dalmatians in this study presented for gastrointestinal clinical signs, including anorexia and vomiting. All animals had increased alanine aminotransferase (ALT) enzyme activity, and 9 of 10 had increased alkaline phosphatase (ALP) enzyme activity. The relative increase in ALT activity was much greater than the relative increase in ALP activity, suggesting a predominantly hepatocellular rather than cholestatic liver disease. The mean hepatic copper concentration for 9 Dalmatians was 3,197 microg/g dry weight liver (dwl) (normal, <450 microg/g). In 5 of these 9 dogs, hepatic copper concentrations exceeded 2,000 microg/g dwl. Necroinflammatory alterations associated with copper-laden parenchymal cells were the notable histopathologic finding. The inflammatory infiltrate was either primarily lymphocytic or neutrophilic. Morphologic features of cholestasis generally were not prominent except in those dogs with severe pathology. These findings lend support to the hypothesis that a primary metabolic defect in hepatic copper metabolism occurs in the Dalmatian breed. The mechanism and genetic basis of this condition require further study.     

A perspective on copper and liver disease in the dog.

Copper is a ubiquitous trace metal necessary for normal function of a variety of cellular proteins. Intracellular copper metabolism is complex, and only a few of the proteins/genes involved are known. Copper deficiency does not appear to be a clinical problem in dogs. Excess copper accumulation in the liver as a cause of hepatitis and cirrhosis was first demonstrated among Bedlington terriers. Subsequently, copper accumulation in the liver has been shown to occur in several other breeds of dogs. Excess hepatic copper has been found in dogs with normal liver histology, dogs with hepatitis, and dogs with end stage cirrhosis. Evidence is accumulating that copper is a cause of liver disease in breeds of dogs other than Bedlington terriers. Moreover, as more data are accumulated, the copper storage disease appears to have characteristics that are very similar among all of the affected breeds.     

Use of zinc acetate to treat copper toxicosis in dogs.

Zinc acetate was used for the treatment and prophylaxis of hepatic copper toxicosis in 3 Bedlington Terriers and 3 West Highland White Terriers. Two dogs of each breed were treated for 2 years, and 1 of each breed for 1 year. A dosage of 200 mg of elemental zinc per day was required to achieve therapeutic objectives related to copper, which included a doubling of plasma zinc concentration to 200 micrograms/dl and a suppression of oral 64 copper absorption. The dosage was later reduced to 50 to 100 mg/day to avoid an excessive increase in plasma zinc concentration. The preliminary clinical results were good. Three dogs had mild to moderate active liver disease and high liver copper concentrations at the time of initiation of zinc administration. Biopsy of the liver 2 years later revealed a reduction in hepatitis and copper concentrations. One other dog without active hepatitis also had a reduction in hepatic copper concentrations over a 2-year period. All 6 dogs have done well clinically. On the basis of these findings, we believe zinc acetate to be an effective and nontoxic treatment for copper toxicosis in dogs.     

Copper toxicosis in the Bedlington terrier: a diagnostic dilemma

Diagnosis of copper toxicosis (CT) in Bedlington terriers by the quantitative and qualitative assessment of copper (Cu) in, and pathology of, biopsies has been largely superseded by a DNA-based assay which uses a microsatellite marker (C04107) linked to the CT disease allele. A retrospective study was conducted comprising 154 liver biopsies from Bedlington terriers with 22 matched DNA markers to compare the two methods in the diagnosis of CT. For the biopsy method, three categories (phenotypes) were identified based on analytical and morphological criteria: 'unaffected' in 83 samples (54 per cent), where Cu was much less than 400 microg/g, and there was an absence of visual Cu or liver damage; 'intermediate' in 18 samples (12 per cent), where Cu was less than 400 microg/g, and there was limited histochemical Cu and no/equivocal damage; and 'affected' in 53 samples (34 per cent), where Cu was greater than 400 microg/g, there was histochemical Cu and liver damage was poorly related to Cu content. In the DNA assay, which was used alone on unrelated individuals, the microsatellite marker failed to identify the CT status of any of the groups. Liver biopsy remains a reliable indicator of Cu accumulation and progressive liver disease in individual dogs. The microsatellite marker C04107 has a predictive value only when supported by a pedigree.     

Copper inhibition of the thiobarbituric acid reaction in Bedlington terriers

The effect of copper on thiobarbituric acid (TBA) reaction values, an index of lipid peroxidation, was examined in Bedlington Terriers, healthy dogs, and rats. High hepatic concentrations of copper appeared to lower TBA values in the inherited, chronic, progressive hepatic degeneration of Bedlington Terriers, a disease associated with copper toxicosis. The suspected TBA inhibition was confirmed when Cu2+ was added to homogenates of healthy dog or rat liver or a malondialdehyde standard. The amount of copper added approximated that in diseased Bedlington Terriers. Because of the interference by copper, the TBA test was judged to be an inappropriate test for the evaluation of lipid peroxidation in samples containing high copper concentrations such as those in diseased Bedlington Terriers.     

Population dynamics of inherited copper toxicosis in Dutch Bedlington terriers (1977-1997)

Inherited copper toxicosis in Bedlington terriers was 1st reported in 1975 and the entire Dutch population was examined from 1976 until the present for presence of the disease. To examine the effect on the prevalence of the disease of excluding affected dogs from breeding we have compared 2 time cohorts, the 1st consisting of dogs born from January 1, 1976, to January 1, 1986 (n = 155), and the 2nd of dogs born from January 1, 1990, to January 1, 1997 (n = 195). The diagnosis was made in the 1st cohort by evaluating liver biopsies, and in the 2nd cohort with a DNA marker. The population was also resolved into clusters of related dogs to analyze the familial distribution of the disease in the population and to search for ancient founders of the disease among the ancestors of sick dogs. Forty-six percent of dogs examined between 1976 and 1986 had copper toxicosis. Eleven percent of dogs examined in the 2nd cohort had evidence of disease. This reduction was achieved while maintaining the already limited genetic heterogeneity of the population: the number of clusters and the mean relatedness between the clusters were similar in both time cohorts. The disease was evenly distributed over the clusters of related dogs in both cohorts. All ancestors had contributed to the distribution of copper toxicosis and no specific founders could be identified. This indicates that when the breed was established in The Netherlands, the disease was already highly prevalent in the founding dogs.     

Use of 2,3,2-tetramine as a hepatic copper chelating agent for treatment of copper hepatotoxicosis in Bedlington terriers

Five Bedlington Terriers with inherited copper (Cu) hepatotoxicosis and with hepatic Cu concentrations ranging from 3,000 to 11,000 micrograms/g of dry weight (normal, less than 350 micrograms/g of dry weight) were treated daily for up to 200 days with 2,3,2-tetramine tetrahydrochloride. During treatment, no change was made in the dietary Cu intake, which ranged from 12 to 16 micrograms/g of dry diet. Concentrations of hepatic and serum Cu, iron, and zinc were determined before and at the conclusion of the treatment period. In one dog, 24-hour urinary Cu concentration was measured before and during treatment. A liver biopsy specimen obtained after treatment had significantly (P less than 0.05) reduced hepatic Cu concentration (3,282 micrograms/g of dry weight; a 54.9% reduction), compared with the pretreatment value (7,281 micrograms/g of dry weight). After treatment, there was an overall general lessening of the extent of hepatic morphologic damage. Cytochemical examination for Cu in rhodanine-stained biopsy specimens revealed decreased numbers of Cu-laden hepatic lysosomes. The mean daily urinary Cu concentration increased as much as 25-fold during 2,3,2-tetramine treatment. Hepatic iron and zinc concentrations and serum Cu concentrations remained within normal ranges after treatment. Clinical or laboratory evidence of 2,3,2-tetramine toxicosis was not detected during treatment. These findings indicated that in affected Bedlington Terriers, 2,3,2-tetramine was a safe and rapid chelating agent of hepatic Cu.     

Evaluation of haplotypes associated with copper toxicosis in Bedlington Terriers in Australia

OBJECTIVE: To evaluate the haplotype distribution associated with the copper toxicosis gene and the segregation of the mutated allele in a Bedlington Terrier population in Australia. ANIMALS: 131 Bedlington Terriers. PROCEDURE: Samples of DNA and RNA were obtained from each dog. Genetic status of each dog was evaluated by use of the DNA markers C04107; single nucleotide polymorphism (SNP), which was adjacent to exon 2 of Murr1; and a deletion marker for exon 2. A subgroup of the study population was evaluated by use of biochemical and histologic techniques to elucidate the correlation between genotype and phenotype. RESULTS: We identified a recombination between the C04107 marker and Murr1 and a variation in a nucleotide in the splice site of exon 2 in our Bedlington Terrier cohort. Furthermore, we identified a novel haplotype associated with copper toxicosis in this cohort. CONCLUSIONS AND CLINICAL RELEVANCE: Our findings indicate that the deletion of exon 2 was not the sole cause of copper toxicosis, although only exon 2 deletion of Murr1 has been responsible for copper toxicosis in Bedlington Terriers. Although we failed to find a novel mutation in our cohort, we identified an affected dog family with an intact exon 2. Furthermore, we found that an SNP in the 5' splicing site of exon 2 may or may not be associated with a novel mutation of the Murr1 gene or other genes. Loss of linkage between the C04107 marker and the Murr1 gene was also identified in a certain family of dogs.     

Polymorphisms in canine ATP7B: candidate modifier of copper toxicosis in the Bedlington terrier

A COMMD1(MURR1) deletion has been reported as the cause of copper toxicosis (CT) in Bedlington terriers. Recent studies identified Bedlington terriers with copper accumulation without homozygous COMMD1 deletions. Wilson disease in humans is a copper storage disorder similar to CT caused by mutations in ATP7B, and COMMD1 has been shown to interact with the ATP7B protein. ATP7B may act as a modifier in CT, allowing for copper accumulation in Bedlington terriers with one deletion or other variations in COMMD1. In this study, ATP7B was cloned and sequence analysis conducted in a subset of Bedlington terriers from a pedigree that does not show complete association between the COMMD1 deletion and CT. Eleven polymorphisms, two in the coding region, were identified in the Bedlington terrier ATP7B gene. However, these are not unique to the Bedlington terrier and pedigree analysis suggests that ATP7B is not a modifier of COMMD1 in this subset of dogs.     

Use of 64Copper Measurements to Diagnose Canine Copper Toxicosis

Inherited canine copper toxicosis is a serious problem in Bedlington terriers and West Highland White terriers, and may also be a problem in other less-studied breeds. Affected dogs become ill at midlife with progressive and ultimately fatal liver disease. Treatments for removal of copper and prevention of copper accumulation are available, but are most effective if begun before the dog becomes ill. Until recently diagnosis has not been available until the dog is 1 year of age, and then only by an invasive liver biopsy with determination of liver copper concentration. The authors studied the use of 64copper for early diagnosis of canine copper toxicosis. Two procedures were evaluated. The first involved measuring the concentration of 64copper in blood 24 hours after oral administration of the radioisotope. At this time, 64copper was associated primarily with ceruloplasmin secreted into the blood by the liver. This procedure is useful in the diagnosis of the human counterpart, Wilson's disease. However, the authors found it to be nondiscriminatory between affected and unaffected dogs. In contrast, the second procedure, which involved measuring 64copper excreted in stool during 48 hours after an intravenous dose of radioisotope, yielded results that differentiated most affected and unaffected dogs.     

Iatrogenic copper deficiency associated with long-term copper chelation for treatment of copper storage disease in a Bedlington Terrier

A 9-year-old Bedlington Terrier was evaluated because of weight loss, inappetence, and hematemesis. Copper storage disease had been diagnosed previously on the basis of high hepatic copper concentration. Treatment had included dietary copper restriction and administration of trientine for chelation of copper. A CBC revealed microcytic hypochromic anemia. High serum activities of liver enzymes, high bile acid concentrations, and low BUN and albumin concentrations were detected. Vomiting resolved temporarily with treatment, but the clinicopathologic abnormalities persisted. Results of transcolonic portal scintigraphy suggested an abnormal shunt fraction. Results of liver biopsy and copper quantification revealed glycogen accumulation and extremely low hepatic copper concentration. Serum and hair copper concentrations were also low. Chelation and dietary copper restriction were tapered and discontinued. Clinical signs and all clinicopathologic abnormalities improved during a period of several months.     

Inherited copper toxicosis in Bedlington terriers

SUMMARY Chronic hepatitis and increased hepatic copper concentrations, from 1,600 to 6,361 fig/g dry tissue were found in 4 related, Australian-bred Bedlington terriers. Two dogs were asymptomatic and 2 were clinically ill with signs referable to liver dysfunction. Two dogs were treated with d-penicillamine. After one year there was no improvement in the histopathological liver changes in either dog or significant lowering of hepatic copper level in one dog.     

Clinical, morphologic, and chemical studies on copper toxicosis of Bedlington Terriers.

In a study of 90 Bedlington Terriers, 68 had a defect that resulted in the accumulation of toxic excesses of copper in the liver. Concentrations of copper were 5 to 50 times that of clinically normal mongrel dogs. The bulk of this excess copper was sequestered in lysosomes. When copper concentrations exceeded 2,000 micrograms/g dry liver, progressive signs of functional and morphologic disturbance appeared as focal hepatitis, chronic active hepatitis, and ultimately cirrhosis. The disorder, which appears to be inherited, could only be diagnosed by liver biopsy. It was latent for many years in some dogs but led early in life to acute or chronic hepatic disease and death in others.     

Microsatellite marker C04107 as a diagnostic marker for copper toxicosis in the Danish population of Bedlington terriers

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.     

Copper,Zinc and Molybdenum in Livers of Norwegian Cattle At Slaughter

The concentrations of copper, zinc and molybdenum were measured in samples of cattle liver from 10 slaughter-houses in Norway. A total of 335 samples were analysed. A clear accumulation of copper with age was found, the average copper level in the younger animals (≦ 3 years, n = 194) being 30 µg Cu/g liver wet weight, and in the older ones (> 3 years, n = 141) 59 µg Gu/g. The range in the copper values found was considerable, though significant differences between some of the districts were recorded. Copper concentrations were classified as low (≦10 µg Gu/g) in 9.6 % of the samples. Zinc showed no accumulation with age, nor were there any differences in zinc levels found in animals from different districts, the average level being 32 µg Zn/g liver wet weight. The picture was the same for molybdenum, no differences between age groups or districts being found. The average level was 1.0 µg Mo/g liver. There was no significant correlation between levels of copper, zinc or molybdenum.The supply of copper and zinc to cattle in Norway seems close to sufficient, but copper- and zinc-fortified mineral supplementation of cattle feed is still to be recommended. There seems to be no need for molybdenum supplementation in cattle.     

Copper storage disease with intravascular haemolysis in a Bedlington terrier

A 5-year-old male Bedlington terrier was found to have haemoglobinuria from intravascular haemolysis. The owners reported also recent vomiting, occasional diarrhoea, reduced activity and increased drinking and urination. A diagnosis of inherited copper storage disease, as previously described in this breed, was established by demonstrating characteristic light and electron microscopic changes and copper content of 7, 717 micrograms/g in biopsied liver. Treatment by chelation with d-penicillamine and a low copper diet was instituted and the dog remains well 10 months later. Intravascular haemolysis is rare in dogs and an uncommon finding in Bedlington terriers with copper storage disease.     

Heavy metals (cadmium, copper, lead and mercury) in common eiders (Somateria mollissima) from Denmark

In an examination of 50 Danish common eiders, the liver and kidney content of cadmium, copper, lead and mercury was determined. Eiders were chosen for analysis, because this species feed almost exclusively on the common mussel (Mytilus edulis), which is known to accumulate heavy metals. The concentrations recorded of cadmium, copper, and mercury were lower than what is usually regarded as toxic for birds, except for one eider which carried more than 2000 mg copper/kg liver tissue (dry weight). Of the 42 eiders analysed for lead, four had toxic levels, i.e., more than 7 mg per kg liver wet weight, and two other had increased levels, i.e., 3-7 mg lead per kg liver wet weight. The mean Cd concentration was 3.3 mg/kg liver (ww). This means that by consumption of ab. 160 gram liver from the common eider, the weekly tolerable intake of cadmium suggested by FAO/WHO would be exceeded.