Constitutional BMF can be a manifestation of germline defect resulting from a loss of function of one or more of the genes involved in DNA repair (Fanconi anemia), telomere maintenance (dyskeratosis congenita and other telomeropathies), and deficiencies leading to hematopoiesis regulation (GATA2, CTLA4) (1). This evidence concerns the gene CTLA4 and Fanconi anemia.