As of 2018, there are more than 25,000 people in the U.S. That suffer from spinal muscular atrophy (SMA). Interestingly, no two people who have been diagnosed with SMA have the same symptoms because there are different types of spinal muscular atrophy. There are four main types of SMA and other lesser developed spinal muscular atrophy illnesses:

1. SMA Type I
This is the more severe and common type of SMA called Werdnig-Hoffmann Disease. Type I is aptly diagnosed when it strikes an infant during their first six months. The Werdnig-Hoffmann Disease leaves babies with the inability to move their muscles. They also will be unable to swallow, to hold their heads up, and labored breathing. Unfortunately, SMA is a disease that progresses quickly forcing the medical staff to insert feeding tubes and tubes to help with breathing. SMA has a fatal outcome for babies.

2. SMA Type II
Following the more severe SMA is Type II. SMA Type II strikes between the ages of 7 and 18 months. Type II SMA also progresses quickly. This disease causes a child’s legs and arms to become weakened robbing them of the ability to move their arms or legs. Breathing problems also affect children with Type II but with medical assistance, children can live with this disease into adulthood. Individuals with Type II can sit up by themselves but will need help in adjusting to a seated position.

3. SMA Type III
SMA Type III is the milder form of this disease. It is known by two names – Kugelberg-Welander or Juvenile Spinal Muscular Atrophy. Type III Juvenile Spinal Muscular Atrophy is denoted in its name, whereby SMA can be diagnosed as late as an individual in their teens. Juvenile Spinal Muscular Atrophy Type III enables people to stand and walk with a little assistance. With Type III SMA, individuals can live a relatively normal lifestyle but as they age, their muscles can weaken making their mobility a limited experience.

4. SMA Type IV
SMA Type IV is somewhat rare for persons is called “adult-onset SMA.” It generally occurs after age 35 but can develop around age 18. Individuals who develop Type IV SMA experience slow muscle weakness and other symptoms. The symptoms are mild muscle weakness in the legs and hips that slowly travel to the arms and shoulders and minor muscle twitches. Life expectancy should be normal with the help of a wheelchair or other mobile device.

5. Other Types of SMA
The remaining types of SMA are considered less rare in nature, including:

• SMARD: Spinal Muscular Atrophy Respiratory Distress (SMARD) is related to SMA Type I but in a milder form. The upper and lower spinal cords are affected. Babies or infants with SMARD experience the same symptoms as Title I.
• Distal SMA: Distal SMA is an inherited disease. There are body weaknesses that affect the hands and feet. Early symptoms involve breathing difficulties which can occur very suddenly. The distal limbs are most affected with mobility becoming more and more affected with near paralysis.
• Kennedy’s Disease: SMA Kennedy’s Disease only affects men. It starts later in adulthood, around ages 30 and 50. The legs and arms are most affected by muscle weakness and muscle cramps and it can affect other muscles like the face. The throat is also affected meaning that speech and swallowing are greatly affected.