SMG9 is a gene that helps protect the body cells from harmful or toxic proteins. This gene works to ensure that the cell produces proteins that are of the correct length. If an error happens and a shorter-than-normal protein is going to be produced (which can be harmful to the cell), it is the job of SMG9 and other related genes to stop the production of such a protein and thus protect the cell. A mutation in this gene can lead to birth defects, as described in the previous sections.
SMG9