The TEFMgene is a nuclear encoded mitochondrial gene that is transported into the mitochondria to form part of the mitochondrial transcription machinery. It is required by the mitochondrial RNA polymerase (POLRMT) for the elongation stage of mitochondrial transcription. All individuals with TEFMrelated disease described so far have shown autosomal recessive inheritance. Of the 7 TEFMvariants published to be associated with disease, 4 are missense variants, 2 are frameshift and 1 is an in-frame 2 amino acid deletion. These TEFMvariants showed relatively high residual activity (hypomorphic alleles) and there is a lack of homozygous loss of function variants in gnomAD. Diagnosis is made following identification of compound heterozygous or homozygous pathogenic variants in TEFM.
TEFM