FANCC encodes a DNA repair protein essential for interstrand cross-link (ICL) repair and chromosome 9 maintenance 1. As a core component of the Fanconi anemia nuclear complex, FANCC functions in postreplication repair and cell cycle checkpoint control, operating within a pathway shared with other FA proteins like FANCA and FANCD2 2. The protein facilitates homologous recombination repair (HRR) and confers sensitivity to PARP inhibitors when deficient, defining a "BRCAness" phenotype therapeutically relevant for cancer treatment 3. Pathogenic FANCC variants cause Fanconi anemia, a rare recessive disorder characterized by bone marrow failure, congenital abnormalities, and malignancy predisposition 4. FANCC mutations represent a minor complementation group in FA populations, with FANCA and FANCG being more prevalent 4. Beyond classical FA, germline FANCC alterations associate with increased breast cancer risk in African American women (OR=3.2-8.5 for ER-positive disease) 5 and pancreatic cancer susceptibility in Asian populations 6. Additionally, FANCC mutations link to primary ovarian insufficiency as part of syndromic presentations affecting fertility 7. These findings establish FANCC as a clinically important DNA repair gene with implications for cancer predisposition screening and PARP inhibitor-based therapeutic selection.