Fanconi's anemia - Retrospective study over a period of 37 years

Fanconi anemia (FA) is a rare disease, with an estimated frequency of 1 to 5 per 1,000,000 births, which may increase in some ethnic group (like Ashkenazi Jewish and Gypsy). It’s an autosomal recessive disease that may have an X-linked transmission. Patients with FA may have congenital malformations, bone marrow failure, hypersensitivity to clastogenic agents, chromosomal fragility, and increased susceptibility to oncological diseases. Due to the great complexity of this pathology, the first approach to diagnosis consists of the detection of chromosomal aberrations (breaks, structural rearrangements, rings) in peripheral blood cells in culture with clastogenic agent such as diepoxybutane (DEB) or mitomycin C (MMC). We intend to present the results of chromosome instability studies induced by DEB and MMC performed in our institution. A retrospective 37 years series (1980-2017) of 274 samples sent to the cytogenetic laboratory with suspicion of FA and 28 samples of relatives of patients with FA were perform. The samples were process according with the protocol established by the International Fanconi Anemia Registry (IFAR). In the 274 analysed samples, 39 cases with AF were identify. In the cytogenetic studies of relatives with AF, 2 positive cases were identified for FA. Abnormal karyotypes were also observed in 8 samples suspected of AF. In this study, 41 new cases of AF were identify, mainly from the Lisbon and Tagus Valley regions and some specific cases from Azores, the central region and from the Portuguese speaking African countries (PALOP). This study evidences that the majority of the presented cases are underdiagnosed. These results do not allow to estimate a frequency of patients with AF in Portugal, since it does not include individuals from all Portuguese regions, and are include two individuals of PALOP origin. It would be interesting to carry out Next generation sequencing on the Fanconi positive samples in order to obtain in a single assay the analysis of the various genes involved in the pathology thus identifying the genetic change causing the disease. The authors have no conflict of interest.N/