TNRC18 is a chr7 reader that mediates silencing of endogenous retroviruses (ERVs) class-I elements, particularly LTR12 1. The protein contains a carboxy-terminal bromo-adjacent homology (BAH) domain that specifically recognizes histone H3 trimethylated at lysine-9 (H3K9me3), and an amino-terminal segment that directly recruits corepressor complexes including HDAC-Sin3 and NCoR complexes to enforce ERV repression 1. This H3K9me3-sensing pathway is critical for epigenetic silencing of evolutionarily young ERVs and substantially affects host genome integrity, transcriptomic regulation, and development 1. Beyond ERV silencing, TNRC18 regulates inflammatory signaling by modulating H3K27 acetylation at inflammatory regulatory regions, influencing IL-1β production in myeloid cells 2. Clinically, TNRC18 variants associate with anterior uveitis, with the same locus sharing genetic connections to ankylosing spondylitis and inflammatory bowel disease 3. Additionally, TNRC18 methylation at regulatory regions associates with kidney function and renal fibrosis 4. Disruption of TNRC18 through balanced translocations correlates with neurodevelopmental delay 5, and TNRC18::RARA fusion generates a variant acute promyelocytic leukemia 6.