A CLASTOGENICITY STUDY WITH DISTINGUISHING FANCONI ANEMIA

Objective: Aplastic anemia is a rare condition characterized by bone marrow failure due to various etiologies including Fanconi anemia. Mitomycin C is an alkylating agent inducing chromosome breaks in aplastic anemia. The clastogenic effect of mitomycin C is most marked in Fanconi anemia. This study aims to demonstrate mitomycin C induced chromosomal breaks in patients with aplastic anemia and distinguish Fanconi anemia patients among them. Material and Method: Clastogenicity test was applied to 147 patients with aplastic anemia, four siblings and 30 healthy controls. Both simultaneous and mitomycin C (MMC) treated lymphocyte cultures were prepared. Chromosome breaks per metaphase were calculated and cytogenetic abnormalities were analyzed. Results: The mean number of chromosome breaks per metaphase increased from 0.02 to 0.37 after MMC treatment in patients with aplastic anemia. This number changed only from 0.01 to 0.16 in the healthy controls. In 25 patients (16.6%), the number of chromosome breaks per metaphase was >= 1 in MMC treated cultures, and MMC treatment induced a significant increase compared to spontaneous culture (2.88 vs 0.35), which assured the diagnosis of Fanconi anemia. We observed various multiple chromosomal aberrations in all of them and accompanying phenotypic features in 20. Conclusion: Mitomycin C induced chromosomal breaks and cytogenetic abnormalities enable the diagnostic differentiation between aplastic anemia and Fanconi anemia.