SMA, or Spinal Muscular Atrophy, is a neurological disease that affects motor nerve cells in the brain and affects mobility, is usually diagnosed in infancy or early childhood, and can lead to death if not treated early. Genetically, it is one of the biggest causes of infant mortality in the world and is a rare disease. With the defect of motor nerve cells in the spinal cord, voluntary muscles are also affected.

Therefore, it leads to loss of basic functions such as walking, eating and breathing. It is one of the diseases with symptoms such as increasing muscle weakness and muscle loss. Unfortunately, there is no definitive cure for SMA disease. SMA is among the most searched diseases on the internet in recent years.

In the human body, most of the nerve cells that control the muscular system are located in the spinal cord. No signal is transmitted from the motor nervous system of a person with SMA to the muscles. In other words, this order does not work systematically in SMA patients as in a healthy individual. This limits the movements of the individual and reduces the quality of life considerably.


Symptoms of SMA may differ from person to person. The main symptom in all forms of the disease is weakness and wasting (atrophy) of voluntary muscles. The variability of the effects of the disease varies according to the age and mobility of the person. Symptoms of the disease can be listed as follows:

  • Muscle wasting and weakness
  • Difficulty sitting and standing
  • inability to walk
  • Difficulty moving the head
  • Difficulty in sucking and feeding
  • Reduction in reflexes
  • cramps and numbness
  • frequent falls
  • inability to balance
  • twitching of the tongue
  • hand tremor


Who has SMA disease, a healthy individual has SM1 and SM2 neurons encoding the SMN protein. If these proteins are not encoded in a systematic order, they cause neurons to die. The SMN protein is important for the function of muscles in the human body. If this protein is not produced, nerve cells lose their function. Damaged spinal cord motor neurons have difficulty controlling the patient’s musculature. Especially sick; he cannot move his legs, arms, neck muscles and head.

The individual with SMA has difficulty in performing some actions that are under the control of the motor nervous system, such as walking and sitting, and cannot do these actions without assistance. The person in SMA disease, which causes destruction in the muscle system in the body; He has no difficulty in using sensory functions such as seeing, tasting, smelling, hearing and touching.


There are 4 different types of SMA disease, which is a neurological disorder and is seen as rarely as 1/10,000 in the world. Since these types differ according to the age and mobility of the patient, they can vary from person to person. The earlier the disease begins, the more difficult the effects and treatment process are for the patient. The 4 forms of SMA disease can be explained as follows:

Tip-1 SMA:

It is the most common form of SMA, especially in infant deaths. It is the most severe and common type of Spinal Muscular Atrophy. It usually occurs in infants 6 months of age or younger. Symptoms can begin while the baby is still in the womb. The baby shows minimal functionality in the womb. A person with Type-1 SMA has difficulty feeding and has respiratory distress. The disease progresses rapidly and causes complications. The disease can cause respiratory tract infection in the future. The baby, whose lungs are narrowed, has to get support from the breathing apparatus.

Tip-2 SMA:

Compared to Type-1 SMA patients, they have a milder disease. Symptoms of Type-2 SMA are usually seen in babies aged 6-18 months, and everything progresses normally before this period. The patient can usually sit up and has no trouble moving his head. But it cannot act alone. Has difficulty standing up without support. It is possible to have curvature of the spine (scoliosis). Symptoms such as tremors in the hands and inability to gain weight are seen.

Tip-3 SMA:

This type is seen after 18 months. SMA symptoms may occur in the patient from the 18th month to adolescence. Respiration may be affected in this type, but not as severely as in the other two types. There is no problem in standing and walking, but there is muscle weakness and it may be difficult to perform functions such as sitting and standing. The patient lags behind in physical activities compared to their peers. As the disease progresses, it may be difficult to run and falls are common. The need to use a wheelchair may arise during adolescence and adulthood.

Tip-4 SMA:

The fourth and final type, Type-4 SMA, occurs with the onset of the disease in adulthood. Type-4 is rare and the progression of the disease is slow. These patients are usually able to walk and rarely need support. Muscle tenderness and weakness may be seen in the arms and legs. Respiratory and swallowing difficulties are rarely observed. It is also possible to see curvature in the spinal cord.


The question of how Spinal Muscular Atrophyis is diagnosed can be answered as follows: The physician, who listens to the patient’s medical history, first examines the patient. Necessary laboratory tests such as blood test, genetic test and nerve and muscle measurement are performed with EMG. If parents notice any abnormality in the baby’s movements, they should consult a physician. If the physician suspects that the baby has Spinal Muscular Atrophyis , the suspected genes of the parents are examined and blood sample testing is used to confirm the diagnosis.

According to the test result, the physician makes the diagnosis to the patient. Spinal muscular atrophy is diagnosed when there are complaints such as limitation of movement and weakness because it affects movement and nerve cells. Spinal Muscular Atrophyis a genetically transmitted disease. Even if the mother and father are not directly sick, they may be carriers and may not be aware of this situation.


One of the main complications of Spinal Muscular Atrophy is a decrease in the ability to control the muscles. The patient especially has difficulty in controlling the arm and leg muscles. In this disease, in which the muscles are the target, respiratory muscles are also damaged. Impaired airflow to the lungs is associated with weakness of the respiratory muscles.

Individuals with SMA should pay attention to respiratory functions and pay particular attention to protection from infections so that the disease does not cause more serious problems throughout their life.

Curvature of the spine (scoliosis) is a frequent complication in Spinal Muscular Atrophyis patients and is a condition that needs intervention. Because the spine is an important building block of the human body and plays an important role in the movement function of the body. Scoliosis, which is caused by the weakening of the muscles supporting the spine, is a disease that reduces the quality of life of the individual and limits movement function.

The age of onset of Spinal Muscular Atrophyis disease and the level of control of motor functions are related to how much usable protein is found in motor neurons. If Spinal Muscular Atrophyis disease is not due to a deficiency of chromosome 5 or SMN protein in the individual, the severity of the disease and the muscles affected may differ from person to person. These may affect distal muscles that are further away from the center of the body, at least initially, as opposed to the chromosome 5 related type.

The later the symptoms begin in chromosome 5-associated Spinal Muscular Atrophyis disease and the more SMN proteins are found in the patient’s body, the milder the course of the disease will be.

In the past years, the onset of SMA in infancy has led to an average life expectancy of two years for the patient. Today, medical professionals accept SMA as a process and believe that such predictions are not correct.

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