Spinal Muscular Atrophy or SMA is a neuro-muscular disorder seen in infants and young children that makes it difficult for them to use their muscles. This disorder affects the nerve cells in the spinal cord and the brain, which restricts normal message transmission from the brain to the body for proper muscle movement. This in turn makes the muscles contract and become weak, thereby leading to problems in sitting, standing, or walking, or even controlling the head’s movement. In worst cases, the child would find it hard to swallow and breathe as well.

SMA is a type of inherited disease, which occurs when both the parents pass one faulty gene each to their child. As the child has two copies of the defective gene, his/her body would not be able to produce a specific protein, which supports the cells that control the muscles. However, if the child gets only one broken gene, he/she would not show any symptoms of the disease but could pass the faulty gene to his/her child in the future.


Spinal Muscular Atrophy is categorized into 4 types, and the symptoms would vary depending upon the type of SMA your child has.

  • Type 1 SMA is the most severe form of the disease. Here, the child would not be able to support his/her head or sit upright. He/she would have floppy arms and legs, and might have difficulties in swallowing and breathing as well.
  • Type 2 SMA is seen to affect children aged between 6 and 18 months. Also known as Chronic Infantile SMA, this type of the disorder would affect the legs of the infant more than his/her arms. However, the child might be able to walk or sit with some help.
  • Type 3 SMA usually affects children who are 2 to 17 years old. Although it is the mildest form of SMA, it affects the motor skills of the child such as running or climbing stairs. This form of SMA is also known as Kugelberg-Welander disease.
  • Type 4 SMA is seen to affect children in their 20’s or even later. The common symptoms here include muscle weakness, frequent shivering, or breathing problems. Generally, this type of SMA affects only the upper arms and the legs.


As there are many different types of Spinal Muscular Atrophy, proper and timely diagnosis of the disease is very important to devise the right treatment plan. Besides, the disorder can be hard to diagnose as well because the symptoms can vary from person to person.

To start the diagnosis, the doctors at community healthcare centers would ask a few questions to the parents such as the following.

  • Has your baby ever faced difficulties in moving his/her head or rolling over?
  • Does he/she have any problems standing or sitting down?
  • Have you ever noticed your baby facing breathing problems?

The healthcare expert can ask a lot more questions depending on the condition of your child. The doctor would also analyze your medical histories to see if you or your spouse has had any similar symptoms. After reviewing the results, the doctor might recommend a few tests to determine the severity of the condition.

The common tests to diagnose SMA include:

  • EMG or nerve test – In this test, the doctor would test how the muscles react when small electrical impulses are sent through the nerves.
  • CT scan – In this test, a powerful X-ray would be taken in order to analyze the extent of the disease.
  • MRI scan – In this test, radio waves and magnets would be used to check if the disease has affected any internal organs and body structures.
  • Muscle tissue biopsy – In this test, the doctor would use a small needle to take samples of the muscle cells and send it to a specialized laboratory for further analysis if needed.


Nusinersen is the only FDA-approved medication to treat SMA at present. Recent studies have shown that it has helped around 40% of patients in slowing down the progression of the disorder. As nusinersen is injected into the spinal cord fluid, it also helps to strengthen the muscles of the patient and promotes better movement. Note that the recovery time after the procedure can take up to 2 hours, and the patient might need multiple shots as well depending upon the severity of the condition.

Apart from the nusinersen therapy, your doctor might also suggest a few simple methods to control the symptoms of SMA. For instance, Type 1 and Type 2 SMA patients are recommended to practice breathing exercises to strengthen the muscles that help to move air in and out of the lungs. If it is too difficult to breathe normally, the doctor might also suggest using a breathing machine to the patient. Similarly, parents are advised to monitor the eating habits of their children with SMA carefully, and use a feeding tube if they see that their child finds it difficult to swallow his/her food.

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    About the Author

    Dr. Ghassan M. Al-Jazayrly, MD

    A graduate of University of Aleppo Faculty of Medicine, Dr. Al-Jazayrly or, as he is colloquially known: Dr. AJ, is an oncologist and hematologist of a Complete Care Community Health Center (CCCHC) with more than 36 years of experience. In recent years, he’s been involved with a non profit organization known as Every Woman Counts (EWC) which provides free breast and cervical cancer screening and diagnostic services to California’s underserved populations in order to eliminate health disparities for low-income individuals.

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