The deficiencies cause increased risk of hemorrhage and recurrent infections, respectively.As FA is now known to affect DNA repair, specifically homologous recombination, and given the current knowledge about dynamic cell division in the bone marrow, patients are consequently more likely to develop bone marrow failure, myelodysplastic syndromes, and acute myeloid leukemia (AML). Myelodysplastic syndromes
MDSs, formerly known as preleukemia, are a group of bone marrow neoplastic diseases that share many of the morphologic features of AML, with some important differences. First, the percentage of undifferentiated progenitor cells, blast cells, is always less than 20%, with considerably more dysplasia, defined as cytoplasmic and nuclear morphologic changes in erythroid, granulocytic, and megakaryocytic precursors, than what is usually seen in cases of AML. These changes reflect delayed apoptosis or a failure of programmed cell death. When left untreated, MDS can lead to AML in about 30% of cases. Due to the nature of the FA pathology, MDS diagnosis cannot be made solely through cytogenetic analysis of the marrow. Indeed, it is only when morphologic analysis of marrow cells is performed, that a diagnosis of MDS can be ascertained. Upon examination, MDS-affected FA patients will show many clonal variations, appearing either prior or subsequent to the MDS. Furthermore, cells will show chromosomal aberrations, the most frequent being monosomy 7 and partial trisomies of chromosome 3q 15.
Observation of monosomy 7 within the marrow is well correlated with an increased risk of developing AML and with a very poor prognosis, death generally ensuing within 2 years (unless prompt allogeneic hematopoietic progenitor cell transplant is an option). Acute myeloid leukemia
FA patients are at elevated risk for the development of AML defined as presence of 20% or more of myeloid blasts in the marrow or 5 to 20% myeloid blasts in the blood. All of the subtypes of AML can occur in FA with the exception of promyelocytic. However, myelomonocytic and acute monocytic are the most common subtypes observed. Many MDS patients diseases evolve into AML if they survive long enough. Furthermore, the risk of developing AML increases with the onset of bone-marrow failure.Although risk of developing either MDS or AML before the age of 20 is only 27%, this risk increases to 43% by the age of 30 and 52% by the age of 40. Historically, even with a marrow transplant, about a quarter of FA patients diagnosed with MDS/ALS have died from MDS/ALS-related causes within two years, although more recent published evidence suggests that earlier allogeneic hematopoietic progenitor cell transplantation in children with FA is leading to better outcomes over time. Bone marrow failure
The last major haematological complication associated with FA is bone marrow failure, defined as inadequate blood cell production. Several types of  failure are observed in FA patients, and generally precede MDS and AML.