A comparative histochemical study performed on cortical brain tissue from patients with Niemann-Pick (McKusick 257200), Tay-Sachs (McKusick 272800), and juvenile amaurotic family idiocy (AFI) (McKusick 204200) and brains from 15 diseased English setters showed the changes in the human juvenile form (204200) and in the diseased dogs were almost identical. The conclusion was that human Batten disease (204200) had a good model in the English setters, and that the stored substance in both was a mixture of lipid and protein (Koppang 1962, 1966; Koppang and Rossner 1965). A selective breeding programme of English setters was initiated in 1960. Breeding experiments established the genetic mode of transmission as an autosomal recessive trait. From 1966, we have been able to breed the number of English setters needed for research (Koppang 1973/74). Clinical, pathological and microscopic examination further characterized the English setter as a model for the juvenile form of HCL. The English setter model has shown the initiation and development of CL as a generalized metabolic disease, starting in the fetus and progressing linearly with increased storage in most of the cells in the body. The neurons in particular are affected and with time will degenerate and die. This loss of neurons produces symptoms and finally death. The average age at death of CL English setters is 24 months (range 17-25 months) (Koppang 1982, 1987, 1988a,b, 1992). As some metabolic diseases have been treated with bone marrow transplantation, we tried this treatment on four English setters with CL. The result was unsuccessful (Deeg et al 1989), as was liver transplantation and treatment with vitamin E, selenium, glutathione enzyme, peroxidase enzyme and Larodopa. However, 20% Maizena oil in the diet, expected to accelerate the disease and shorten life span, gave the CL dogs better quality of life than treated groups. Our conclusion (Koppang 1987) was that the result is scarcely in accordance with the current hypothesis on CL and may indicate the need for further discussion on the pathogenesis of the disease. Jolly et