MTTL1 is a mitochondrial gene that encodes a transfer-RNA molecule. Specifically, this tRNA is responsible for the transfer of the amino acid leucine to its correct position during mitochondrial protein translation. It is hence designated as tRNA-Leu (UUR). The gene is also required for transcription termination of the mitochondrial genome. The mitochondrial transcription termination factor (MTERF) binds to a 13 bp termination sequence located within the MTTL1 gene.
The gene has been implicated in several mitochondrial disorders including MELAS Syndrome, Leigh Syndrome, Maternally Inherited Diabetes and Deafness (MIDD), Sudden Infant Death Syndrome (SIDS), Cyclic Vomiting Syndrome (CVS), Mitochondrial Complex IV Deficiency, Age Related Macular Degeneration 1 (ARMD1) and Myoclonic Epilepsy associated with Ragged-Red Fibers (MERRF).