MT-RNR2 and inborn mitochondrial metabolism disorder: Functional mutations to MT-RNR1 and MT-RNR2 are similarly uncommon in the germline mitochondrial disease literature, where only 2 of 94 of known pathogenic germline variants identified in the MITOMAP database19 (m.1555A>G and m.1494C>T, associated with aminoglycoside-induced hearing loss, but not bona fide mitochondrial disease) arise in either rRNA gene, compared to 50 of 94 variants in the mitochondrial tRNAs (Extended Data Fig. 3a).