Spinal Muscular atrophy: everything you need to know

Spinal Muscular atrophy: everything you need to know

Is your kid struggling to control head movements, sit without assistance, and even walk? Chances are that your baby might have Spinal Muscular Atrophy (SMA). In the United States, August is observed as Spinal Muscular Atrophy Awareness Month. Let’s know more about this disease & help spread awareness about this rare neuromuscular disease.

Spinal Muscular atrophy is a hereditary neuromuscular disease that affects the muscles and can lead to extreme muscle weakness, inability to use your muscles, and wasting away of the skeletal muscles (atrophy). It is most commonly seen in infants and kids and is caused due to missing or mutated(faulty) SMN 1 & 2(survival of motor neuron) genes that lead to a loss of motor neurons (the specialized nerve cells that control muscle movement). As the disease progresses, you may even have difficulty swallowing and breathing. 


There are several types of SMA, and the severity of the condition depends on which type your child has. 

SMA type 0: It’s the rarest and most severe form of the condition that develops even before your baby is born. Affected babies move less in the womb, and frequently have joint deformities when they are born (contractures). At birth, they have extremely low muscle tone (hypotonia), and respiratory muscles are extremely weak (they frequently die before reaching the age of one due to respiratory failure). Some infants have birth defects in their hearts (congenital). 

SMA type 1/Werdnig-Hoffmann disease: It’s the most commonest and presents as muscle weakness at birth (or within the first few months). Many affected babies are unable to control their head movements or sit without assistance and may have swallowing issues (which can lead to difficulty feeding and poor growth). They may also have breathing difficulties (due to respiratory muscle weakness) and an abnormally bell-shaped chest that prevents the lungs from fully expanding. Because of respiratory failure, most babies don’t survive past early childhood. 

SMA type2/Dubowitz disease: Also called chronic infantile SMA, it’s characterized by muscle weakness in babies aged 6 to 12 months. Infants of this type can sit, though they may require assistance. However, as the muscle weakness worsens, they are unable to stand or walk. They also have involuntary trembling (tremors) in their fingers, a spine that curves side to side (scoliosis), and life-threatening respiratory muscle weakness. Individuals with SMA type 2 may live into their twenties or thirties. 

SMA type 3/ Kugelberg-Welander disease/Juvenile SMA: Type 3 is evident as muscle weakness after childhood. Individuals with this condition can stand and walk without assistance but walking and climbing stairs may become increasingly difficult over time. Many affected people will need wheelchair assistance later in life. People with type 3 usually live normal life. 

SMA type 4: Spinal muscular atrophy type 4 is rare and begins in early adulthood. Affected people typically experience mild to moderate muscle weakness, tremors, and mild breathing difficulties and usually have a normal life expectancy. 


The main cause of SMA is either a missing portion of the SMN1 (survival of motor neuron) gene or a faulty (mutated) gene. SMN protein is produced by the SMN1 gene and is required for motor neurons to function properly. Due to less/faulty SMN protein, the motor neurons die, and the brain is unable to control voluntary movements (particularly those involving the head, neck, arms, and legs). 

Mutations in other genes cause other rare forms of SMA like SMN2 or non-chromosome 5. 


The symptoms of SMA differ depending on the type. The spinal cord contains most of the nerve cells that control your muscles (which explains why the disease’s name includes the word spinal). SMA is muscular in nature because it affects muscles, which do not receive signals from these nerve cells. Atrophy is the medical term for wasting away, which is what muscles do when they are not stimulated by nerve cells. 

People with SMA show a progressive loss of: 

  • Muscle control,  
  • Muscle movement, and 
  • Muscle strength.  

Muscle loss worsens with age. The muscles closest to the torso and neck are vulnerable. In severe SMA patients never walk, sit, or stand.  


SMA can be hard to diagnose. Your doctor might take a detailed history and order several tests like: 

  • Creatine kinase (CK) levels (blood test) 
  • Genetic tests 
  • Nerve tests such as Electromyogram (EMG) 
  • CT (Computerized Tomography) scan 
  • MRI (Magnetic Resonance Imaging) 
  • Muscle tissue biopsy 

Stay connected with your medical team for support while your child fights this disease. Call us on 718-DORAL-55 to speak to the best neurologists in Brooklyn. 


There is no cure for SMA, and the treatment revolves around the severity of the disease.  

  • Medications like Nusinersen (Spinraza), Onasemnogene abeparvovec-xioi (Zolgensma), and Risdiplam (Evrysdi) work on the genes that cause SMA (SMN1 and SMN2 genes). 
  • In some cases, physical therapy, and assistive devices (such as orthopedic braces, crutches, walkers, and wheelchairs) are extremely helpful. 

 There is no cure for SMA, but proper diagnosis and treatment can alleviate some symptoms and, in some cases, extend your child’s life. Researchers are looking for new ways to combat the disease.

Looking for more information or a second opinion? 

At Doral Health and Wellness, we have doctors that can help you manage your condition. For more information, you can visit us at 1797 Pitkin Avenue, Brooklyn, New York, 11212, or call us at 1-347-384-5690. You can also visit our website at https://doralhw.org or contact us at info@doralhw.org if you have any queries. 


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