Spinal muscular atrophy, or SMA, refers to a non-curable disease that causes the deterioration of nerve cells, impacting the brain to spinal cord signals required for muscle control, function, and overall movement. SMA is most often presents in newborn babies, infants, and young children. While SMA does not affect the brain as far as overall intelligence, it impacts movement with symptoms of uncoordinated movements (i.e., head and neck), swallowing difficulties, muscle weakness and wasting, and an inability to sit, crawl, or walk. SMA can’t be cured, however, with proper treatment, patients may live a full, more comfortable lives.

SMA is a genetic disease, meaning it’s caused by a broken gene passed on by both parents. So a child must inherit the gene mutation from both parents to develop SMA. However, if he or she only has one broken gene from a single parent, he or she can still be a carrier and pass the disease on to his or her child (if his or her partner has the same broken gene). The type of gene mutation determines the type of SMA present, for instance:

1. SMA type 1
SMA type 1 is the most devastating from of the disease. SMA. It often presents with early warning signs in newborns that may include—swallowing issues, uncontrolled or weak arms and legs, and the inability to support the head and neck to sit up without assistance. Small children with type 1 SMA often have severe respiratory difficulties that lead to early fatality (before 2-years old).

2. SMA type 2
Chronic infantile SMA, or SMA type 2, mostly impacts infants between the ages of 6- to 18- months of age. Early warning symptoms include :

• Mild to severe respiratory (breathing) problems
• Decreased muscle tone (hypotonia)
• Abnormal muscle contractions (twitching or fasciculations)
• Decreased reflexes, particularly in the legs
• Unable to sit, walk, or stand without assistance

3. SMA type 3
Also known as juvenile SMA or Kugelberg-Welander disease, type 3 is the mildest form of SMA. This type typically strikes between the ages of 2- to 17-years of age with few symptoms early on. In fact, many patients with SMA type 3 are able to sit, stand, and walk without support. However, they often develop issues later on and eventually require wheelchair assistance.

4. SMA type 4
Develops in adulthood. This type of SMA can vary dramatically between patients. For instance, many only experience mild symptoms—including muscle twitches, shortness of breath, and muscle weakness, particularly in the upper arms and legs—throughout life. However, physical therapy and daily exercise can help significantly improve symptoms and overall quality of life so much so that patients may continue to work and lead relatively normal lives.