Transmembrane channel-like 1 (Tmc1) mutation causes hearing loss, and cationic lipid-mediated in vivo delivery of Cas9:gRNA RNP complex in the humanized transmembrane channel-like 1 (Tmc1) Beethoven (Bth) mouse model ameliorated the pathogenic phenotype (64). The gene discussed is TMC1; the disease is hearing loss disorder.