HCSMA Case Studies
Case Study: Hereditary Canine Spinal Muscular Atrophy
Hereditary canine spinal muscular atrophy (HCSMA) is proven to be an autosomal-dominate disease that affects most noticeably the Brittany spaniel (Pinter MJ, Waldeck RF, Wallace N, & Cork LC, Motor Unit Behavior in Canine Motor Neuron Disease, 1995). HCSMA originated as a spontaneous mutation in the Survivor Motor Neutron gene found in the purebred Brittany spaniel population (Ericsson. A & Rubin. C, 2012). Due to the co-dominate nature of the disease there are slight variation in the phenotype expressed in the diseased population, the homozygous individuals will be affected by the disease much earlier than the heterozygous individuals (Pinter MJ, Waldeck RF, Wallace N, & Cork LC, 1995). The co-dominate nature of the genes affects the severity of the disease, homozygous HCSMA affects the individual much earlier and disease is accelerated, whereas heterozygous HCSMA causes intermediate traits or chronic disease in the individual (Sack GH Jr, Cork LC, Morris JM, Griffin JW, & Price DL, 1984). Dogs that are homozygous for HCSMS will start to develop muscle weakness by 1.5 months and quadriparetic by 3 months of age. Through experimental breeding, the experimenters discovered that the HCSMA affects both sexes equally, thus proving the disease to have no linkage to the sex chromosomes (Sack GH Jr, Cork LC, Morris JM, Griffin JW, & Price DL, 1984).
Hereditary canine spinal muscular…