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| − | ==Description==
| + | *due to an inherited deficiency of lysosomal enzymes |
| − | Lysosomal storage diseases occur due to inherited deficiencies of various lysosomal enzymes and this may be due to abnormalities in their synthesis, processing or cellular trafficking. The normal function of lysosomes is to degrade molecules within the cell and, when these chemical reactions are truncated by the absence of a key enzyme, the substrates of the reaction accumulate within the organelle. Since there is some redundancy in the pathways by which proteins are degraded, deficiencies in proteases do not usually result in clinical disease. Deficiencies in the nuclease enzymes are also not usually compatible with survival.
| + | *manifest themselves as neurological disease |
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| − | There are a large number of different lysosomal storage diseases in dogs and cats categorised according to the product which accumulates within cells. All of the storage disease are rare.
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| − | *Excess accumulation of metabolites in lysosomes
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| − | *Affects mainly nervous system | |
| − | *Also affects growth of cartilage
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| − | ===Classification===
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| − | {|cellpadding="10" cellspacing="0" border="1"
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| − | | '''Class'''
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| − | | '''Defective Enzyme'''
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| − | | '''Name of Disease'''
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| − | | '''Sphingolipidosis'''
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| − | | beta D gangliosidase<br>
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| − | beta D hexosaminidase<br>
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| − | beta D glucocerebrosidase<br>
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| − | beta D galactocerebrosidase<br>
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| − | Sphingomyelinase
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| − | | GM1 Gangliosidosis<br>
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| − | GM2 Gangliosidosis<br>
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| − | Gaucher Disease<br>
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| − | Krabbe Disease<br>
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| − | Niemann-Pick Disease
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| − | | '''Oligosaccharidosis'''
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| − | | '''Mucopolysaccharidosis'''
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| − | | '''Glycoproteinosis'''
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| − | | '''Proteosis'''
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| − | ===Pathophysiology===
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| − | The clinical syndrome produced in each of the lysosomal storage disease results from the aberrant storage of metabolites within cells. The storage diseases usually affect multiple organs but some, such as those that are caused by a defect in the myelin degradation pathway, may only cause neurological signs.
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| − | The mucopolysaccharidoses involve a failure to degrade glycosaminoglycans (major components of cartilage) and they often involve skeletal deformity.
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| − | ==Diagnosis==
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| − | ===Clinical Signs===
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| − | Many of the lysosomal storage diseases are associated with neurological signs.
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| − | ===Laboratory Tests===
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| − | Lysosonal storage disease often result in changes in leucocytic morphology which can be detected on a blood smear.
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| − | {|cellpadding="10" cellspacing="0" border="1"
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| − | | '''Disease'''
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| − | | '''Finding on blood smear'''
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| − | ===Diagnostic Imaging===
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| − | ===Other Tests===
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| − | Since genetic techniques have become more widely available and easily performed, it is often possible to characterise the genetic defect directly by determining the sequence encoding enzymes thought to be deficient. However, it should be remembered that several lysosomal storage diseases result from alterations in post-translational processes such as cellular trafficking.
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| − | ==Treatment==
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| − | ==Prognosis==
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| − | ==Test yourself with the Liver Pathology Flashcards==
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| − | [[Liver_Flashcards_-_Pathology|Liver Pathology Flashcards]]
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| − | (LSD)
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| − | * Occurs in many breeds of dogs and cats.
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| − | * Genetic defects give deficiencies of specific enzymes of degradation.
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| − | ** Disease only occurs in animals homozygous at the gene pair controlling enzyme activity.
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| − | *** The genes are co-dominant.
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| − | ** Enzyme activity is extremely low or entirely absent.
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| − | * Large amounts of waste products accumulate within cells.
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| − | ** Nervous system cells are predisposed.
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| − | ** Cells become engorged.
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| − | ** Normal function is prevented.
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| − | * [http://w3.vet.cornell.edu/nst/nst.asp?Fun=Display&imgID=20531 Image 1, courtesy of Cornell Veterinary Medicine] <BR>
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| − | * [http://w3.vet.cornell.edu/nst/nst.asp?Fun=Display&imgID=20530 Image 2, courtesy of Cornell Veterinary Medicine]
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| − | * [http://w3.vet.cornell.edu/nst/nst.asp?Fun=Display&imgID=20185 Image 3, courtesy of Cornell Veterinary Medicine]
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| − | ===Clinical Signs===
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| − | * Nervous system cells are predisposed to the disease, and so progressive neurological signs predominate.
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| − | ** Develop between 2 weeks and 12 months of age.
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| − | ** The disease is ultimately fatal.
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| − | * For example, Siamese cats show:
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| − | ** Ganglisidosis
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| − | ** Mucopolysaccharidosis
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| − | ===Diagnosis===
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| − | * Clinical signs are considered.
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| − | * Urine enzyme assays may be helpful.
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| − | * Post-mortem diagnosis is possible.
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| − | * More recently, gene tests have been available.
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| − | ==References==
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| − | {{unfinished}}
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| − | [[Category:Central Nervous System - Degenerative Pathology]]
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| | [[Category:Liver - Storage Diseases]] | | [[Category:Liver - Storage Diseases]] |
| − | [[Category:To_Do_-_Neurological]][[Category:To Do - Medium]][[Category:To Do - Alimentary]]
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| − | [[Category:Liver Diseases - Dog]][[Category:Neurological Diseases - Dog]]
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| − | [[Category:Liver Diseases - Cat]][[Category:Neurological Diseases - Cat]]
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| − | [[Category:Bones - Developmental Pathology]]
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