Spinal Muscle Atrophy (SMA) is a health condition or a group of genetic disease which causes physical weaknesses in the human body. It affects the performance of the motor nerve cells of our spinal cord. A person with SMA losses the ability to eat, walk, or breathe due to acute physical weakness caused by the disease. However, SMA does not interfere with the ability to learn, think, and building relationships with others.
The symptoms of SMA are more prevalent in infants and children. Researchers have estimated that one in every 7,000 to 11,000 babies worldwide are born with SMA. It is one of the most known genetic conditions among children. It is caused due to a mutation of the survival motor neuron 1 (SMN1) present in the spinal cord.
1. Spinal Muscle Atrophy (SMA): Types and symptoms
Medical science has categorized SMA into four primary types: Type I, II, III, and IV. These Spinal Muscle Atrophy (SMA) types are based on the age of onset and the physical changes. It is to be noted that patients with SMA may not have identical experiences, symptoms, or disease progression. Hence, the treatment decisions and processes are individualized based on a specific diagnosis.
2. Spinal Muscle Atrophy (SMA) Type I
This is one of the most known and severe types of SMA. SMA Type I is mostly diagnosed in infants below six months. A child with SMA Type I experiences physical challenges such as trouble in swallowing, breathing, coughing, etc. Babies with SMA Type I require assistance to breathe and eat. Researchers have observed that this type of SMA can be fatal. Symptoms of SMA Type I also include frequent respiratory infections, weak trunk movement, and floppy limbs. This condition is also referred to as Werdnig-Hoffmann disease.
3. Spinal Muscle Atrophy (SMA) Type II
SMA Type II usually gets diagnosed in children who are six months to two years old. The prime sign of SMA Type II is a delay in their motor skills. In rare cases, individuals fail to meet the motor milestones completely. The prime impact area of this disease are the legs; hence, babies with SMA Type II are unable to stand. In addition, respiratory infections are also common. However, children with SMA Type-II can sit up without help in most cases, though they may need help to stay in that position.
4. Spinal Muscle Atrophy (SMA) Type III
This type of SMA is usually diagnosed in children between 18 months and three years of age. Furthermore, this can be diagnosed in early adulthood too. An individual diagnosed with SMA Type III can initially walk but slowly experiences an inability in movement as they grow. Eventually, they become wheelchair-bound. They may also develop uneasiness when sitting. The symptoms of SMA Type III is also called juvenile SMA or referred to Kugelberg-Welander disease.
5. Spinal Muscle Atrophy (SMA) Type IV
It is a rare condition which surfaces during the second or third decade of life. SMA Type IV leads to progressive muscle weakness and can lead to mild motor impairment.