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

Inherited copper toxicosis in Bedlington terriers was Ist reported in 1975 and the entire Dutch population was examined from 1976 until the present fo r presence of the disease. To examine the effect on the prevalence of the d isease of excluding affected dogs from breeding we have compared 2 time coh orts, the Ist consisting of dogs born from January I, 1976, to January 1, 1 986 (n = 155), and the 2nd of dogs born from January 1, 1990, to January 1, 1997 (n = 195). The diagnosis was made in the Ist cohort by evaluating liv er biopsies, and in the 2nd cohort with a DNA marker. The population war, a lso resolved into clusters of related dogs to analyze the familial distribu tion 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 ex amined between 1976 and 1986 had copper toxicosis. Eleven percent of dogs e xamined in the 2nd cohort had evidence of disease. This reduction was achie ved while maintaining the already limited genetic heterogeneity of the popu lation: the number of clusters and the mean relatedness between the cluster s were similar in both time cohorts. The disease was evenly distributed ove r the clusters of related dogs in both cohorts. All ancestors had contribut ed to the distribution of copper toxicosis and no specific founders could b e identified. This indicates that when the breed was established in The Net herlands, the disease was already highly prevalent in the founding dogs.