Spinal Muscular Atrophy (SMA) is a genetic disorder where the body doesn't produce enough of a protein called SMN (survival motor neuron) protein, leading to the shrinking and death of motor neurons.
Here's a breakdown:
- The Problem: People with SMA have a deficiency in the SMN protein.
- The Cause: This deficiency is typically due to a mutation or deletion in the SMN1 gene. The SMN2 gene can produce some SMN protein, but not enough to compensate in most cases.
- The Effect: The lack of SMN protein causes motor neurons (nerve cells in the spinal cord that control muscle movement) to deteriorate.
- The Result: This deterioration leads to muscle weakness and atrophy (wasting away), making it difficult or impossible to control voluntary movements. These movements include head control, neck control, chest and leg movements.
Key Aspects of SMA:
- Genetic: SMA is inherited.
- Motor Neuron Degeneration: The primary issue is the loss of motor neurons.
- Muscle Weakness: Muscle weakness is the most prominent symptom.
- Voluntary Movement Impairment: Affects control over movements like breathing, crawling, walking, and head movement.
In essence, SMA is a genetic condition characterized by insufficient SMN protein, resulting in motor neuron degeneration and progressive muscle weakness.
