Spinal muscular atrophy is an inherited disease that attacks the motor neuron nerve cells and is characterized by progressive muscle degeneration and weakness.
- Infantile Progressive Spinal Muscular Atrophy (SMA Type 1)
The most severe form of SMA causes infants to have poor muscle tone, progressive muscle weakness, lack of head control, trouble swallowing and sucking, and breathing problems.
- Intermediate Spinal Muscular Atrophy (SMA Type 2)
Children’s with intermediate SMA may have weakness in the arms, legs, upper and lower torso in addition to joint deformities.
- Juvenile Spinal Muscular Atrophy (SMA Type 3)
Juvenile SMA is the least severe form of the disease and is characterized by weakness in the leg, hip, shoulder, arm and respiratory muscles.