Final answer:
Spinal muscular atrophy (SMA) typically presents with symmetric weakness. It is a genetic disorder that affects the nerve cells responsible for controlling voluntary muscle movement.
Step-by-step explanation:
Spinal muscular atrophy (SMA) typically presents with symmetric weakness. This means that the weakness affects both sides of the body equally. SMA is a genetic disorder that affects the nerve cells responsible for controlling voluntary muscle movement. It is characterized by progressive muscle weakness and atrophy.