Molecular basis of Fanconi anemia

Fanconi anemia (FA) is an autosomal recessive disease characterized by pancytopenia, congenital malformation and high predisposition to developing malignancies. The phenotypical heterogeneity is associated with genetic heterogeneity: at least 8 complementation groups (FA-A to FA-H) have been identified, each group presumably corresponding to a separate disease gene (FAA to FAH). The FAA and FAC genes, which account for 75-80% of the patients, have been cloned. Their protein products have no significant homology to any known protein, or to each other, and may therefore represent elements of a new pathway. This review describes some of the recent contributions to the understanding of the molecular basis of FA.

The authors of the present review have been working in the field of FA for several years. In the present review they have critically examined articles published in journals covered by the Science Citation Index and Medline.

A variety of biochemical and cellular approaches have been used to determine the molecular defect of FA. Evidence for a possible role of the defective proteins in cell cycle regulation, apoptosis, or DNA stability have been reported. Recently, it has been demonstrated that FAA and FAC proteins bind each other and form a complex found in similar abundance in both cytoplasm and nucleus, suggesting a possible function in nucleus activities. Knowledge of the mutation spectrum occurring in the FA genes may contribute significantly to pathogenesis studies in FA and help to design mutation screening strategies. Further functional studies and the cloning of other FA genes will provide insights into the biological basis of FA and information for developing specific therapies for the disease.