Functions+of+the+SMN+Protein

Lack of the SMN protein is the main cause of SMA. There are two genes that "make" this protein; SMN1, and SMN2. SNM1 makes a lot more of the SMN protein than SMN2. When SMN1 is deleted from an individual's DNA instructions, all that is left is the gene for SMN2, which does not make enough of the SMN protein for the individual to function normally. The main job of the SMN protein is to provide maintenence for motor neuron cells, which control the movement of muscles in the back and neck. These motor neurons are located in the brain stem and spine. (What is Spinal Muscular Atrophy) The figure below shows the lack of SMN production from the SMN2 and the full production of SMN fro the SMN1 gene.