TRIT1 and Mitochondrial myopathy: The convergence of two different mechanisms, one due to a mutation in the TRIT1 enzyme and the other to a mutation in its substrate mt-tRNASer(UCN), that both cause i6A37 hypomodification of mt-tRNASer(UCN) and mitochondrial myopathy, provide strong genetic evidence of the critical importance of i6A37 in mitochondrial translation.