Sometimes we come across diseases that are breed specific and Ganliosidosis GMI and GM2 are two such diseases. This disease has now been associated with the Korat one of the oldest breeds of cat, originating from Thailand. It is ironic that the Thai name for Korat means good luck when these poor felines are affected by these two, Gangliosidosis GMI and GM2 genetic diseases.
Gangliosidosis is one of the lysosomal storage diseases. These diseases are associated with the part of the cell that is responsible for breaking down and recycling vital chemicals needed for brain function and other important activities. There are over 40 diseases which surface in humans because of the malfunctioning lysosome enzymes. In Humans Gangliosidosis is the culprit in Tay Saks Disease. Siamese cats are also affected by this disorder as well as other animal species; dogs, cows and sheep.
What is Gangliosidosis?
Gangliosidosis is the accumulation of gangliosides at the cellular level. This excess accumulation is due to the fact that enzymes known as beta-galactosidase have not properly broken down the gangliosides which are compound chemicals made up of several sugar and sialic acids (n-acetylneuraminic acid). The gangliosides are differentiated on the basis of their positioning on the sugar chain at the molecular level of the plasma membrane (cell membrane).
GMI is important for proper physiological brain functioning. They are involved in the process of Neuroplasticity which aids in the brain changes that occur as a result of new experiences. They also aid in brain repair, and they release a brain chemical or neurotransmitter called neurotrophins. Some forms of diarrhea such E Coli are a result of the malfunctioning at this site in the cell membrane.
Sandhoff Disease is caused by Feline Gangliosidosis GM2. This disease causes continual damage to the spinal cord and brain cells. Cats will have enlarged livers or other organs, and neurological impairment and leg paralysis. Effected cats will lose motor control, have seizures, distorted vision, cherry eye (red in the eye) and bone degeneration.
Symptoms
GM1 gangliosidosis first presents itself in 3-month-old kittens, while GM2 ganglisidosis show up about a month earlier, however the progression of the disease is slower.
At first these kittens will have tremors of the head, then difficulty with muscle leg coordination and finally leg paralysis.
Diagnosis
Veterinarians will use various diagnostic tests to determine if the disease is present. They will look for the clinical symptoms, take urine samples, blood tests to check for sugar, a skin biopsy, MRI for determining brain lesions, and a light microscopy in cases where the cat has died. Though these diseases share commonalities with all human and animal species affected, diagnosis can be made specific to the cat since each breed or species will have its own gene structure mutation. It is possible to test for just mutations on GM1 and GM2 gene for Korat cats.
Treatment
There isn't a specific treatment for gangliosidosis.
Carriers
Gangliosidosis is an inherited (autosomal) recessive gene disorder which affects both sexes of felines equally. When Korats mate, if they carry this recessive gene, there is a twenty-five percent change that they can pass on the gene to their offspring. In other words twenty-five percent of the kittens will have both genes from their parents and thus exhibit neurological damage. Even when two normal felines mate, half of their offspring will not have the disease but will be carriers. These numbers are alarming. Even though the phenotype of the cat seems normal, visual inspection alone can not determine if the genotype carries the recessive gene.
New Prevention Method
Dr. Henry Baker maintains that genotype can be tested through DNA analysis administered by a separate blood test for GM1 and GM2. Dr. Baker and his colleagues at the Scott-Ritchey Research Center at Auburn University researched Gangliosidosis for the past twenty years and can administer such a test.
There is still hope. Two Korat cats that have two copies of the normal genes can be determined and given the seal of approval for mating to produce healthy offspring; therefore reducing the risk of carriers producing even more carriers as time goes on.
|
