The spinal muscular atrophy is a collection of diseases that are transmitted genetically which can lead to the wasting and the weakness of the voluntary muscles of the children and the infants but is rarely found to be affecting the adults. This is one of the most common genetic diseases that is found to be affecting the children.

Here we have briefly discussed the various types of spinal muscular atrophy the severity and the life span of the patient under each type of this genetic disease greatly differs:

1. Type 0
This type of spinal muscular atrophy is classified by a reduced fetal movement observed at the time of pregnancy. At the time of birth, the patients who have spinal muscular atrophy type 0 are seen to have hypotonia and severe weakness. Usually, such patients have a minimum reaction to stimuli, facial paralysis or facial diplegia as well as congenital defects of the heart. Such patients lose their lives by the time they are six months old or maximum have a life span of one year.

2. Type 1
In this type of spinal muscular atrophy, the patient is said to have symptoms observed right from their birth or maximum by the time they are six months old. This type of spinal muscular atrophy is called Werdnig-Hoffmann disease or infantile onset. Mostly, in this type of spinal muscle atrophy, babies have weakened muscles, a weak cry and face distress while breathing. They usually face trouble while sucking and swallowing and do not achieve the simplest sitting position. They need external help to do so.

3. Type 2
This type of spinal muscle atrophy appears when the child is between the ages of three and fifteen months. At this stage, they are not able to stand or walk independently. This type of spinal muscular atrophy is also termed as Dubowitz disease or intermediate SMA. the muscles of the lower limbs are usually found to be affected as compared to the upper limbs.

4. Type 3
This type of spinal muscular atrophy is also called Juvenile onset as it appears between 18 months and adulthood. Such symptoms are observed in a person between the age of eighteen months and adulthood. The patients who suffer from this type of spinal muscular atrophy are mobile independently. But since there is a weakness in them they may fall or face difficulty while climbing the staircase. Over time, a lot of people with this type of spinal muscular atrophy tend to lose the ability to walk and stand, hence they have to use a wheelchair to move around. Such patients may face weakness of the respiratory muscles, scoliosis and develop deformities of the foot.

5. Type 4
This is the late onset of spinal muscular atrophy and comprises around five percent of such cases. It is usually found in the person after they have turned thirty. This type of spinal muscular atrophy is mild and the life expectancy of such patients is also normal. Such patients are observed to keep up with their ability to move and achieve the development milestones throughout their life.