Spinal Muscular Atrophy

Test Overview:

Spinal muscular atrophy (SMA) is an inherited disorder that appears similar to the disease of the same name seen in humans.  It is seen in Maine Coon cats, and is inherited as an autosomal recessive disorder, meaning that a copy of the mutation is passed to an affected kitten from both parents. The disease affects the nerve cells in the spinal cord that travel to skeletal muscle of the body (trunk) and legs.  These nerve bodies are lost in the first few months of life, leading to weakness and wasting of the muscles of the body.  Signs are generally first seen at 15 - 17 weeks of age, and initial signs include weakness in the hind legs and a very fine tremor in the muscles.  Kittens will tire easily and will develop an odd gait, with a swaying in the hindquarters.  By 5 months of age they are generally too weak to jump, and examination reveals that muscles of the limbs and body are reduced in size. The condition is progressive, and initially worsens quite quickly, however it is not painful and generally not fatal.  The condition generally stabilises with the cat suffering a variable degree of weakness and loss of mobility.  Cats are not incontinent, but can have a restricted range of mobility and exercise intolerance.  Affected cats are disabled and with care and lifestyle changes are able to live comfortably indoors.  There is a genetic test available for this disease, and breeding animals can be tested to ensure two carriers are not mated, which will prevent affected kittens from being produced.