MTFMT and hyperinsulinemic hypoglycemia, familial, 4: Mutations in the mitochondrial methionyl-tRNA formyltransferase (MTFMT) gene were first identified using targeted sequencing of the mitochondrial and nuclear encoded mitochondrial proteome (MitoExome) in two unrelated patients with Leigh syndrome and combined complex I deficiency and complex IV deficiency (Tucker et al., 2011).