FANCG (FA complementation group G) is a DNA repair protein that functions as a core component of the Fanconi anemia (FA) pathway, the largest cellular defense network integrating over 30 key players in DNA damage response signaling 1. FANCG operates in interstrand DNA cross-link repair and maintains chr9 stability through a postreplication repair or cell cycle checkpoint mechanism 2. The protein localizes to the nucleus and forms complexes with other FA proteins, particularly FANCA, to coordinate cellular responses to DNA damage 2. FANCG mutations cause Fanconi anemia, a rare autosomal recessive disorder characterized by chr9 fragility, hypersensitivity to DNA cross-linking agents, progressive bone marrow failure, and predisposition to myelodysplastic syndrome and acute myeloid leukemia in adolescence and early adulthood 3. FANCG accounts for approximately 25% of FA cases in Japanese populations and is one of the three most prevalent FA complementation groups globally 4. While FANCG is a candidate tumor suppressor, heterozygous germline variants do not significantly contribute to breast or ovarian cancer risk in non-FA populations 5. FANCG deficiency does not directly affect telomere maintenance, suggesting accelerated telomere shortening in FA patients is secondary to the disease process 6.