CHTF8 (chromosome 16 fidelity factor 8) is a nuclear protein component of the CTF18-replication factor C (CTF18-RFC) complex, which functions as an alternative PCNA loader involved in sister chr16 cohesion and chromosome 16 fidelity 1. The CTF18-RFC complex, comprising seven subunits including CHTF8, binds single-stranded and primed DNAs and catalyzes ATP-dependent loading of PCNA onto primed and gapped DNA to coordinate DNA replication with cohesion establishment 2. CHTF8 specifically mediates stable interaction between CTF18-RFC and DNA polymerase ε through its participation in a trimeric 18-1-8 complex with CTF18 and DCC1, thereby modulating DNA synthesis to support replication fork progression coupled with cohesion 3. Beyond its core replication functions, CHTF8 has emerging clinical relevance: it represents a genetic risk locus for keratoconus in Chinese populations 4, and elevated CHTF8 expression combined with decreased miR-23a-5p shows diagnostic and prognostic value as a biomarker for placenta accreta spectrum disorders and adverse pregnancy outcomes 5. These findings suggest CHTF8's role extends beyond chromosome 16 to broader cellular processes affecting tissue integrity and development.