What Is
Spinal Muscular Atrophy?
Spinal Muscular Atrophy (SMA) is a genetic disease that causes the death of nerve cells, leading to paralysis and muscle weakening throughout the body. Other symptoms include scoliosis (curve of the spine), thin limbs, and respiratory failure. While they may be physically frail, people with SMA still show their intelligence, social skills, and mental strength as they traverse through life with this condition.

Genetics
SMA is caused by a lack of the SMN1 gene, which codes for Survival Motor Neuron (SMN) protein. SMN protein is responsible for the survival of motor neurons, which are responsible for controlling body movement. Located in the spinal cord, these neurons signal for contractions in the arms, legs, chest, face, throat, and tongue. Without the SMN1 gene, motor neurons become degenerated and can die. The subsequent disruptions in the signals between motor neurons and muscles cause the muscles to gradually weaken, begin wasting away, and develop twitching. As the body rapidly decreases in functional neurons, a person loses control of breathing, their mouth, and other skeletal muscles. However, there is a back-up gene to SMN1 gene, called SMN2. While this gene also produces SMN protein, it often creates incorrect variants that are unable to work. On average, only 10% of the body's needed SMN protein is created by SMN2 genes. However, people are able to have more copies than normal, decreasing the severity of SMA. This leads to different levels of Spinal Muscular Atrophy, from 0 to 4, each becoming progressively less impactful. (Those with Type 0 die during childbirth, while those with Type 4 become affected throughout adulthood.)
Treatments
Various treatments have been made to help slow the progression of SMA. They are more effective for younger individuals, as once the disease has progressed, there are more dead motor neurons, which are unable to be regenerated in the body. Go to the website of the therapies listed below for more specific information.
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Treatments Include:
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Spinraza: This treatment alters the SMN2 gene to produce more protein. Children and adults with SMA can both use this treatment. Including preparation, injecting the drug, and recovery time, this can take at least 2 hours and will need to be done several times, followed by another dose every 4 months. Studies show it helps about 40% of people who use it by making them stronger and slowing the disease.
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Zolgensma: In this method, the mutated SMN1 gene is replaced with a functional version in the body. This is done through injecting the patient with a virus coded to insert the correct SMN1 gene, and is a one-time treatment. It is only applicable to children under 2 years old. In studies, Zolgensma helped children with SMA reach certain developmental milestones faster, like controlling their heads or sitting without support.
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Evrysdi: This treatment helps SMN protein created from SMN2 to be functional instead of trying to correct the SMN1 gene. A child takes the drug once a day after a meal. The dosage is determined by their weight. Clinical trials showed improved muscle function after 12 months in 41% of those taking it.
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More treatments are being developed to fight for a future where SMA is part of the past.
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