Originally appeared: January 2021 Newsletter
Spinal muscular atrophy (SMA) is a genetic neuromuscular disorder affecting the part of the nervous system that controls the movement of voluntary muscles, in other words, the muscles you can control, such as those in your arms and legs. In SMA, there is a loss of important cells in the spinal cord. These cells are called motor neurons and are essential for muscle movement and strength. These motor neurons regulate muscle activity by sending signals from your central nervous system (CNS) to the voluntary muscles.
The loss of functioning motor neurons leads to gradual muscle weakness and the reduction in muscle mass and strength (atrophy), because your muscles stop receiving signals from the CNS.
SMA affects approximately one in 11,000 newborns. Unlike many other neuromuscular disorders, we do know the specific genetic cause of SMA.
REFERENCES:
Markowitz J, Singh P, Darras B. Spinal Muscular Atrophy: A Clinical and Research Update. Pediatr Neurol. 2012;46(1):1-12.
Mercuri E, Finkel R, Muntoni F et al. Diagnosis and management of spinal muscular atrophy: Part 1: Recommendations for diagnosis, rehabilitation, orthopedic and nutritional care. Neuromuscular Disorders. 2018;28(2):103-115.
Kolb S, Kissel J. Spinal Muscular Atrophy. Neurol Clin. 2015;33(4):831-846.