Spinal muscular atrophy is a condition in which the body’s muscles are unable to function properly due to genetic malfunction. This can hinder muscle development as the body grows and weaken one’s arms, legs, and other muscular parts. It may occur in newborns too. The condition is categorized into different types according to when symptoms manifest. This article looks at the different types of spinal muscular atrophy that are known about.

1. Type 1
Also known as the Werdnig-Hoffmann disease, this type of SMA occurs in newborns. Babies may show symptoms soon after birth or within the first six months. Usually, parents will know if their babies have SMA or not by the time they cross three months. This is because, by then, they begin to show signs like the inability to swallow food or keep their head straight. Babies may also require support to hold or reach out to something as their arms may feel extremely weak. This type of SMA needs utmost care as it is life-threatening.

2. Type 2
Children with type 2 SMA develop symptoms between seven and eighteen months. Unlike type 1 that affects the arms primarily, type 2 targets the leg muscles. Affected children may not be able to walk, which means they will need to be given support or be carried around. Toddlers may also experience trouble breathing and may find it difficult to control this condition while they are asleep. Life expectancy relies on the severity of symptoms and can range from infancy to adulthood.

3. Type 3
Also known as Juvenile Spinal Muscular Atrophy, type 3 SMA leads to visible symptoms in patients from the age of eighteen months to their teens. While children may be able to walk around and stand by themselves, they are likely to have trouble getting up once they sit down due to muscle weakness. As they grow older, some individuals may require a wheelchair for additional assistance. Another symptom that may occur during type 3 SMA is the development of infections in the respiratory tract; however, this condition can be managed. It is mild in comparison to the previous types, and life expectancy is considered to be nearly normal for patients.

4. Type 4
This type of SMA is rare, and signs of the disease may appear only in one’s twenties or thirties. Some individuals may not even notice symptoms until they are much older. In certain cases, however, one may often feel like their arms and legs have little strength. Despite this, people may be able to move about easily and live life without much discomfort. The symptoms during type 4 may improve gradually over time if adequate care is taken. Life expectancy is normal and isn’t usually altered by the condition.