Sma disease: SMA involves the loss of nerve cells

SMA involves the loss of nerve cells called motor neurons in the spinal cord and is classified as a motor neuron disease . In the most common form of SMA (chromosome 5-related SMA, or SMN-related SMA), there is wide variability in age of onset, symptoms, and rate of progression. Spinal muscular atrophy ( SMA ) is a lower motor neuron disease with autosomal recessive inheritance. The first cases of SMA were reported by Werdnig in 1891. Although the phenotypic variation of SMA led to controversy regarding the clinical entity of ... Spinal muscular atrophy ( SMA ) is characterized by muscle weakness and atrophy resulting from progressive degeneration and irreversible loss of the anterior horn cells in the spinal cord (i.e., lower motor neurons) and the brain stem nuclei. The onset of weakness ranges from before birth to adulthood. The weakness is symmetric, proximal greater than distal, and progressive. Before the genetic basis of SMA was understood, it was classified into clinical subtypes based on maximum motor function ... What is spinal muscular atrophy ( SMA )? Spinal muscular atrophy ( SMA ) is a group of genetic diseases that damages and kills motor neurons. Motor neurons are a type of nerve cell in the spinal cord and lower part of the brain. They control movement in your arms, legs, face, chest, throat, and tongue. As the motor neurons die off, your muscles start to weaken and atrophy (waste away). The muscle damage gets worse over time and can affect speaking, walking, swallowing, and breathing. What are ...