Clinical signs and neuropathologic abnormalities in working Australian Kelpies with globoid cell leukodystrophy (Krabbe disease).
OBJECTIVE
To characterize the clinical signs of globoid cell leukodystrophy (GLD) in Australian Kelpies from a working line (AWKs) and determine whether an association existed between these signs and degrees of demyelination and inflammatory responses in affected brains.


METHODS
Case-control study.


METHODS
4 AWKs with GLD (cases) and 7 unaffected young adult dogs of mixed breeding (controls).


METHODS
Clinical records were reviewed for information on signalment, and samples of neurologic tissues underwent histological processing, immunohistochemical staining, and image analysis. Findings were compared between case and control dogs.


RESULTS
The 4 affected AWKs had progressive ataxia, tremors, and paresis and low leukocyte activity of galactosylceramidase, the lysosomal enzyme deficient in GLD. Image analysis of neurologic tissue revealed globoid cells characteristic of GLD and substantial demyelination in the peripheral and central nervous systems, relative to that in neurologic tissue from control dogs. This was accompanied by microglial activation, reactive astrocyto-sis, and axonal spheroid formation.


CONCLUSIONS
The demyelination, inflammatory responses, and axo-nal spheroids evident in the AWKs were consistent with the clinical signs of peripheral nerve, spinal cord, and cerebellar dysfunction. Because GLD is an autosomal recessive inherited disease, with considerable overlap in galactosylceramidase activity existing among heterozygotes and noncarriers, development of a molecular test is important for preventing the perpetuation of this disease in the Australian Kelpie breed.
Fletcher
Jessica L
JL
Faculty of Veterinary Science, University of Sydney, Camperdown, NSW, Australia.
Williamson
Peter
P
Horan
David
D
Taylor
Rosanne M
RM
D000818:Animals; D001921:Brain / Q000473:pathology; D004283:Dog Diseases / Q000175:diagnosis* / Q000473:pathology; D004285:Dogs; D005260:Female; D005698:Galactosylceramidase / Q000097:blood; D007965:Leukodystrophy, Globoid Cell / Q000175:diagnosis / Q000473:pathology / Q000662:veterinary*; D008297:Male; D012584:Sciatic Nerve / Q000473:pathology
D005698:Galactosylceramidase