[The canine neuronal ceroid-lipofuscinosis: a review]

Neuronal ceroid lipofuscinosis (NCL) is caused by the entire deletion of CLN8 in the Alpenländische Dachsbracke dog

Neuronal ceroid lipofuscinoses (NCLs) are inherited lysosomal storage diseases that have been described in a variety of dog breeds, where they are caused by different mutations in different genes. However, the causative gene defect in the breed Alpenländische Dachsbracke remained unknown so far. Here we present two confirmed cases of NCL in Alpenländische Dachsbracke dogs from different litters of the same sire with a different dam harboring the same underlying novel mutation in the CLN8 gene. Case 1, a 2-year-old male Alpenländische Dachsbracke was presented with neurological signs including disorientation, character changes including anxiety states and aggressiveness, sudden blindness and reduction of food intake. Magnetic resonance imaging (MRI) scans showed cerebral atrophy with dilation of all cerebral ventricles, thinning of the intermediate mass of the thalamus and widening of the cerebral sulci. Postmortem examination of the central nervous system (CNS) showed neuronal loss in the cerebral cortex, cerebellum and spinal cord with massive intracellular deposits of ceroid pigment. Additional ceroid-lipofuscin deposits were observed in the enteric nervous system and in macrophages within spleen, lymph nodes and lung. Ultrastructural analyses confirmed NCL with the presence of osmiophilic membrane bounded lamellar-like structures. Case 2, a 1,5-year old female Alpenländische Dachsbracke was presented with progressive generalized forebrain disease including mental changes such as fearful reactions to various kinds of external stimuli and disorientation. The dog also displayed seizures, absence of menace reactions and negative cotton-ball test with normal pupillary light reactions. The clinical and post mortem examination yielded similar results in the brain as in Case 1. Whole genome sequencing of Case 1 and PCR results of both cases revealed a homozygous deletion encompassing the entire CLN8 gene as the most likely causative mutation for the NCL form observed in both cases. The deletion follows recessive inheritance since the dam and a healthy male littermate of Case 1 were tested as heterozygous carriers. This is the first detailed description of CLN8 gene associated NCL in Alpenländische Dachsbracke dogs and thus provides a novel canine CLN8 model for this lysosomal storage disease. The presence of ceroid lipofuscin in extracerebral tissues may help to confirm the diagnosis of NCL in vivo, especially in new dog breeds where the underlying mutation is not known.

Neuronal ceroid lipofuscinosis in an adult American Staffordshire Terrier

A female, 5-year-old American Staffordshire Terrier with severe progressive neurological deficits, particularly in terms of ataxia and keeping balance, was examined pathomorphologically and a genetic analysis was performed. In neurons of various localizations of the central nervous system an accumulation of a finely granular pale eosinophilic or light brown material was found. In addition, the cerebellum revealed marked degeneration and loss of Purkinje and inner granule cells. The accumulated PAS-positive, argyrophilic, autofluorescent material showed ultrastructurally a lamellar appearance suggestive of lipofuscin. Genetic analysis revealed the presence of a sequence variant in the ARSG gene encoding the lysosomal enzyme arylsulfatase G. This case report describes an adult-onset of a neuronal ceroid lipofuscinosis that shows similarities with a human disorder termed Kufs disease.

Moving past serology: Diagnostic options without serum

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Traditional serology has moved beyond blood as a test medium.

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A number of different samples and tissues are now frequently used in veterinary diagnosis.

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Testing can be robust and accurate and opens up the field to a variety of new opportunities.

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Molecular testing allows direct testing for the agent on a variety of tissues and samples, and pools.

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Pooling of samples can allow for more efficient and cost-effective testing.

Detecting antibodies formed in serum in response to infection is the traditional function of serology. Diagnostic modalities have included complement fixation tests, agar gel immune-diffusion, radioimmunoassay, ELISA and immunofluorescence. More recent technology now allows for the direct detection of pathogens by PCR. This review details the options for diagnostic testing using specimen types other than serum, identifying the advantages and disadvantages of these options and providing evidence for more widespread use of these techniques and specimen types.