4 types of spinal muscular atrophy

Spinal muscular atrophy (SMA) is a group of genetic disorders that lead to the progressive degeneration of motor neurons in the spinal cord, causing muscle weakness and atrophy.

SMA is classified into four types—Type I, II, III, and IV—each with distinct symptoms and levels of severity. The condition is caused by a mutation in the survival motor neuron 1 (SMN1) gene, which is essential for the proper functioning of motor neurons. Without sufficient levels of the SMN protein, these neurons fail to send signals to muscles, resulting in gradual muscle wasting.