The TEFMgene provides instructions to make a protein that helps control how mitochondria (the energy factories of our cells) produce important molecules. Although TEFM is made in the main part of the cell (the nucleus), it travels into the mitochondria where it works together with other proteins to help copy mitochondrial genes—a process that’s essential for normal energy production.
People with TEFM-related disease have a gene alteration (or variant) in both copies of their TEFMgene, they inherit one from each parent. This is called autosomal recessive inheritance. So far, seven different changes in the TEFMgene have been linked to the condition. These include four small changes that alter a single building block in the protein (missense mutations), two that disrupt the protein’s structure (frameshift mutations), and one small deletion that removes two amino acids.
Most of these changes still allow the TEFM protein to work a little bit, but not well enough—these are called “partially working” or hypomorphic variants. It seems that genetic changes that cause the TEFMgene to not work at all (also called, complete loss of TEFM function) are very rare or may not be compatible with life.
Diagnosis of TEFM-related disease made after a genetic test looking for TEFMvariants.
TEFM