There's a group of enzymes called N-terminal acetyltransferases (NAT) that do something important with proteins. They add a small part called an acetyl group to the beginning of a protein, in a process that is called N-terminal acetylation. This process is crucial for proteins to work well, affecting how they connect with other proteins, where they are placed in cells, and how they fold.
One of these NAT enzymes is called NatB, and it consists of two subunits: NAA20 and NAA25. The NAA20 subunit is encoded by the NAA20 gene. Having two copies mutated of the NAA20 gene has been linked to develop "NAA20-related syndrome."
In vitro studies have shown that the ability of the enzymes to perform their function is reduced in the presence of a mutation. However, both copies of the gene need to be mutated for the syndrome to occur. Future research is needed to better understand the complexity of the development of this syndrome.