Common Signs and Symptoms of Spinal Muscle Atrophy (SMA)
Medical professionals consider spinal muscular atrophy, also known as SMA, a hereditary motor neuron disease that impacts the lower motor neuron-nerve cells within the brainstem and spinal cord, which are responsible for voluntary muscle control. SMA gradually destroys the lower motor neurons and the patient’s ability to control movement in the face, tongue, throat, chest, arms, and legs, by disrupting signals from the brain to the muscles, and causing severe muscles spasticity (or stiffness), muscle wasting and fasciculations (uncontrolled twitching), and eventual and total loss of voluntary muscle movement. SMA is considered fatal as patient’s will eventually suffer a complete loss of chest muscle function, and succumb to respiratory failure.
What Is Spinal Muscular Atrophy and Its Causes?
SMA occurs due to a deficiency in the survival motor neuron (SMN) protein, caused by mutations in the SMN1 gene. This hereditary condition follows an autosomal recessive pattern, meaning both parents must carry the defective gene for a child to develop SMA. The disease primarily affects motor neurons, leading to muscle weakness and progressive deterioration of muscle function.
What Are the Early Signs of SMA Type 1?
SMA Type 1, also known as Werdnig-Hoffmann disease, typically presents before 6 months of age. Common signs include:
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Severe muscle weakness
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Difficulty breathing and swallowing
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Limited head control
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Inability to sit without support
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Bell-shaped chest due to respiratory muscle weakness
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Weak cry and cough
How Does SMA Type 2 Present in Children?
SMA Type 2 manifests between 6 and 18 months of age with distinct characteristics:
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Ability to sit independently but cannot stand or walk
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Progressive weakness in legs and arms
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Respiratory difficulties
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Fine tremors in fingers
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Scoliosis development
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Joint contractures
What Are the Characteristics of SMA Type 3?
SMA Type 3, or Kugelberg-Welander disease, develops after 18 months of age. Key symptoms include:
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Initial ability to walk independently
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Progressive muscle weakness
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Frequent falls and difficulty climbing stairs
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Tremors
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Scoliosis development
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Fatigue with physical activity
What Treatment Options Are Available for SMA?
Current treatment approaches for SMA include:
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FDA-approved medications like nusinersen and risdiplam
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Gene replacement therapy
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Physical therapy and occupational therapy
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Respiratory support
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Nutritional support
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Orthopedic interventions for scoliosis
| Treatment Type | Provider/Medication | Key Features | Approximate Annual Cost* |
|---|---|---|---|
| Gene Therapy | Zolgensma | One-time treatment | £1.79 million per dose |
| SMN2 Splicing Modifier | Spinraza | Intrathecal injection | £450,000 first year |
| Oral Medication | Evrysdi | Daily oral solution | £340,000 per year |
*Prices, rates, or cost estimates mentioned in this article are based on the latest available information but may change over time. Independent research is advised before making financial decisions.
Early diagnosis and intervention are crucial for managing SMA effectively. The availability of new treatments has significantly improved outcomes for many patients, particularly when treatment begins before significant symptoms develop. Regular monitoring and a comprehensive care approach involving multiple specialists remain essential components of SMA management.
This article is for informational purposes only and should not be considered medical advice. Please consult a qualified healthcare professional for personalized guidance and treatment.
