Early detection of canine ceroid-lipofuscinosis (CCL): an ultrastructural study.

English setters from the Koppang line have been used as a model for the juvenile type of Batten disease in human patients. This disorder, canine ceroid-lipofuscinosis (CCL), has been shown by Koppang [1973: Mech Ageing Dev 2:421-445] to be an autosomal recessive disorder. Homozygous animals show the typical storage granules by autofluorescence; however, the autofluorescence material cannot easily be detected in affected dogs before age 3-6 months. At the present time the early stages of CCL can be studied only in litters from homozygous matings. Electron microscopy was used to study the reliability of diagnosing affected animals in heterozygous-heterozygous (HET-HET) and heterozygous-homozygous (HET-HOM) litters at age 2-3 weeks. The electron micrographs of brain biopsies were examined and the number of all dense bodies (d.b.), including linear and fingerprint patterns typical of CCL, were counted per neuron. The results indicated that affected animals have higher numbers of dense bodies than nonaffected carriers. Four-6 months later confirmatory diagnoses were made on a second contralateral biopsy taken and examined as a frozen section by autofluorescence. The diagnoses made by electron microscopy at age 2-3 weeks appeared identical to the results obtained by autofluorescence at 4-6 months of age.