What is Spinal Muscular Atrophy (SMA)?
Spinal Muscular Atrophy (SMA) is a rare genetic disorder that affects the motor nerve cells in the spinal cord. These nerves are responsible for muscle movement, and when they are damaged, children may experience progressive muscle weakness and loss of motor function. SMA primarily affects crawling, walking, sitting, and head control.
What Causes SMA?
SMA is caused by a mutation in the SMN1 gene, which produces the survival motor neuron (SMN) protein. This protein is essential for the proper functioning of motor neurons. A lack of this protein leads to the degeneration of these neurons, resulting in muscle atrophy.
SMA is inherited in an autosomal recessive pattern, meaning both parents must carry the faulty gene for the child to be affected.
Symptoms of SMA in Children
Symptoms can vary based on the type (Type 1 to Type 4), but common signs include:
- Poor muscle tone (floppy baby syndrome)
- Difficulty holding up the head
- Delayed milestones like crawling or walking
- Weak cough or trouble breathing
- Swallowing difficulties
- Muscle twitching or tremors
How is SMA Diagnosed?
A combination of tests are used for diagnosis:
- Genetic Testing: Confirms mutation in the SMN1 gene
- Electromyography (EMG): Evaluates muscle response
- Muscle Biopsy (rarely required): Shows atrophic muscle fibers
- Clinical Evaluation: Observing muscle strength and motor milestones
Early diagnosis is crucial to manage the disease effectively.
Treatment Options for SMA
While there is no cure, several treatment options can improve quality of life and slow disease progression:
- Gene Therapy: e.g., Zolgensma (for Type 1 SMA)
- SMN-boosting drugs: Spinraza (Nusinersen) or Evrysdi
- Physiotherapy & Occupational Therapy
- Respiratory Support
- Nutritional Support: Address feeding and swallowing difficulties
FAQs About SMA
Q. Can SMA be detected before birth?
A. Yes, carrier screening and prenatal genetic tests can identify the risk.
Q. Is SMA fatal?
A. Type 1 SMA can be life-threatening in infancy without treatment. Other types have a better prognosis with ongoing care.
Q. Will my child walk or talk with SMA?
A. It depends on the type and severity. With early intervention, children may achieve better motor milestones.
When to Consult a Pediatric Neurologist?
If your child shows signs of muscle weakness, delayed motor milestones, or trouble with breathing/swallowing, consult a pediatric neurologist immediately. Early diagnosis and intervention can significantly improve outcomes.
Contact Dr. Neelu Desai
Child Neurologist, P. D. Hinduja Hospital
Mumbai | 022 67668181 / 022 45108181