Spinal Muscular Atrophy in Maine
Maine Michigan State University University California San Diego National Center
SMA is a disorder caused by death of spinal cord neurons that activate skeletal muscles of the trunk and limbs. Loss of neurons in the first few months of life leads to muscle weakness and atrophy that first becomes apparent at 3-4 months of age. Affected kittens develop an odd gait with a sway of the hindquarters and stand with the hocks nearly touching. They may also stand with toes out in the front. By 5-6 months of age they are too weak in the hindquarters to readily jump up on furniture and often have a clumsy landing when jumping down. The long hair MC may hide it, but careful feeling of the limbs will reveal reduced muscle mass. Affected kittens are not in pain, they eat and play avidly, they are not incontinent, and most live very comfortably as indoor cats for many years. As of this writing, the oldest affected cats of which we know are 8-9 years of age. Known affected kittens have occurred in breeding programs across the United States
Studies have demonstrated that the disorder is inherited as a simple autosomal recessive trait. For a kitten to have the SMA disorder, it must receive the mutated copy (allele) of the disease gene from both parents, and male and female kittens are equally affected. The parents of affected kittens show no outward signs of disease, but they are obligate carriers, by definition. In a breeding program, both male and female carriers will pass on their mutant alleles to 50% of all their offspring, on average. When two carriers are inadvertently mated, on average 25% of the kittens will have SMA. That means that in litters from such matings, there may be some combination of SMA and normal kittens, all SMA kittens, or all normal kittens. Unidentified carriers in breeding programs continue to spread the mutant gene throughout the MC breed.
SMA in MC is caused by large deletion on cat chromosome A1 that removed 2 genes. Identification of the SMA mutation has allowed design of a laboratory test to detect the deletion in DNA from cat cheek cells, blood, or frozen semen. DNA isolated from samples is subjected to a polymerase chain reaction (PCR) to amplify the portion of the genome harboring the deletion. Normal and deleted alleles are differentiated by the size of the amplification products separated by agarose gel electrophoresis. Carrier cats can be positively identified in the laboratory on the basis of both the mutant and normal allele PCR products amplifying from their DNA. If one thinks a kitten may be affected, the test can also be used for definitive diagnostic confirmation.
Katzens screens for SMA by DNA. We are a SMA free cattery. We take our testing very serious. We are the only known breeder in this area that tests for SMA. This is the future and health of the Maine
This information does not replace Veterinary advice nor care. If in question please see your Veterinarian.
Spinal Muscular Atrophy in
SMA is a disorder caused by death of spinal cord neurons that activate skeletal muscles of the trunk and limbs. Loss of neurons in the first few months of life leads to muscle weakness and atrophy that first becomes apparent at 3-4 months of age. Affected kittens develop an odd gait with a sway of the hindquarters and stand with the hocks nearly touching. They may also stand with toes out in the front. By 5-6 months of age they are too weak in the hindquarters to readily jump up on furniture and often have a clumsy landing when jumping down. The long hair MC may hide it, but careful feeling of the limbs will reveal reduced muscle mass. Affected kittens are not in pain, they eat and play avidly, they are not incontinent, and most live very comfortably as indoor cats for many years. As of this writing, the oldest affected cats of which we know are 8-9 years of age. Known affected kittens have occurred in breeding programs across the
Studies have demonstrated that the disorder is inherited as a simple autosomal recessive trait. For a kitten to have the SMA disorder, it must receive the mutated copy (allele) of the disease gene from both parents, and male and female kittens are equally affected. The parents of affected kittens show no outward signs of disease, but they are obligate carriers, by definition. In a breeding program, both male and female carriers will pass on their mutant alleles to 50% of all their offspring, on average. When two carriers are inadvertently mated, on average 25% of the kittens will have SMA. That means that in litters from such matings, there may be some combination of SMA and normal kittens, all SMA kittens, or all normal kittens. Unidentified carriers in breeding programs continue to spread the mutant gene throughout the MC breed.
SMA in MC is caused by large deletion on cat chromosome A1 that removed 2 genes. Identification of the SMA mutation has allowed design of a laboratory test to detect the deletion in DNA from cat cheek cells, blood, or frozen semen. DNA isolated from samples is subjected to a polymerase chain reaction (PCR) to amplify the portion of the genome harboring the deletion. Normal and deleted alleles are differentiated by the size of the amplification products separated by agarose gel electrophoresis. Carrier cats can be positively identified in the laboratory on the basis of both the mutant and normal allele PCR products amplifying from their DNA. If one thinks a kitten may be affected, the test can also be used for definitive diagnostic confirmation.
Katzens screens for SMA by DNA. We are a SMA free cattery. We take our testing very serious. We are the only known breeder in this area that tests for SMA. This is the future and health of the
This information does not replace Veterinary advice nor care. If in question please see your Veterinarian.
bravenet.com