Spinal Muscular Atrophy Maine Coon Type (SMA)
Spinal muscular atrophy Maine Coon type is a genetic disorder of Maine Coon cats. It is a neurodegenerative 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, are usually too weak to jump and stand with the hocks nearly touching. By 5-6 months of age, severe weakness in the hindquarters is apparent and muscle mass is reduced. Affected cats are not in pain and most live very comfortably as indoor cats for many years.
Spinal Muscular Atrophy (SMA) – Genetics
The genetic cause of the recessive spinal muscular atrophy Maine Coon type in cats, involving a large deletion on cat chromosome A1 removing two genes. This disorder is inherited as a autosomal recessive trait. Affected kitten carried two mutated alleles of the disease, inherited from both parents. Parents may show no signs of disease, but in this case are obligated carriers.
Fyfe, J. C., Menotti-Raymond, M., David, V. A., Brichta, L., Schäffer, A. A., Agarwala, R., O’Brien, S. J. (2006). An ~140-kb deletion associated with feline spinal muscular atrophy implies an essential LIX1 function for motor neuron survival. Genome Research, 16(9), 1084–1090. http://doi.org/10.1101/gr.5268806 PMID: 16899656
Iannaccone, S. T. (2005). Feline Spinal Muscular Atrophy. Pediatric Research, 57(3), 322–323. http://doi.org/10.1203/01.PDR.0000153671.11277.83