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). The gene discussed is MT-RNR2; the disease is hearing loss disorder.