Muscle weakness and atrophy are symptoms of spinal muscular atrophy (SMA), which is caused by the gradual degeneration and permanent loss of the anterior horn cells in the spinal cord (i.e., lower motor neurons) and the brain stem nuclei. Weakness can appear at any age, from before birth through maturity. The weakening is symmetric, gradual, and proximal > distal. Before the genetic basis of SMA was discovered, it was divided into clinical categories depending on the highest level of motor function obtained; however, it is now obvious that the phenotype of SMN1-associated SMA is a continuum with no distinct subgroups. Poor weight gain with growth failure, restrictive lung disease, scoliosis, and joint contractures are typical consequences with supportive care alone; however, newly accessible targeted therapy approaches are altering the illness's natural history.
Published Date: 2021-06-26; Received Date: 2021-06-19