Chromosomal Breakage in Fanconi Anemia and Consanguineous Marriages: A Social Dilemma for Developing Countries

Fanconi anemia (FA) is a rare genetic instability syndrome characterized by developmental defects, bone marrow failure, and a high cancer risk. Fifteen genetic subtypes have been distinguished. The majority of patients (≈85%) belong to the subtypes A (≈60%), C (≈15%) or G (≈10%), while a minority (≈15%) is distributed over the remaining 12 subtypes. All subtypes seem to fit within the “classical” FA phenotype, except for D1 and N patients, who have more severe clinical symptoms. Since FA patients need special clinical management, the diagnosis should be firmly established, to exclude conditions with overlapping phenotypes. A valid FA diagnosis requires the detection of pathogenic mutations in a FA gene and/or a positive result from a chromosomal breakage test. Identification of the pathogenic mutations is also important for adequate genetic counselling and to facilitate prenatal or preimplantation genetic diagnosis. Here we describe and validate a comprehensive protocol for the molecular diagnosis of FA, based on massively parallel sequencing. We used this approach to identifyBRCA2,FANCD2,FANCIandFANCLmutations in novel unclassified FA patients.

Download Full-text

Fanconi Anemia: Prenatal Diagnosis in 30 Fetuses at Risk

PEDIATRICS ◽

10.1542/peds.76.5.794 ◽

1985 ◽

Vol 76 (5) ◽

pp. 794-800

Author(s):

Arleen D. Auerbach ◽

Michal Sagi ◽

Barbara Adler

Keyword(s):

At Risk ◽

Prenatal Diagnosis ◽

Fanconi Anemia ◽

Chorionic Villus ◽

Chromosome Breakage ◽

The Other ◽

Chorionic Villus Sampling ◽

Chromosomal Breakage ◽

Born Infant ◽

In Cells

We report our experience, since 1978, with prenatal diagnosis in fetuses at risk for Fanconi anemia. Amniotic fluid cells from 30 fetuses from 24 families were monitored for baseline and diepoxybutane-induced chromosomal breakage. Seven of the fetuses at risk were diagnosed as affected; baseline and diepoxybutane-induced breakage ranged from 0.18 to 0.45 and 0.69 to 0.96 breaks per cell, respectively. The range of baseline and diepoxybutane-induced chromosomal breakage in amniocytes from the 23 pregnancies at risk that were diagnosed prenatally as unaffected ranged from 0 to 0.08 and 0 to 0.13 breaks per cell, respectively. Four of these cases were also diagnosed as normal on the basis of chromosomal breakage studies in cells obtained by chorionic villus sampling. The range of baseline and diepoxybutane-induced breakage in cells from five control fetuses was 0 to 0.05 and 0 to 0.10 breaks per cell, respectively. Of the pregnancies diagnosed as affected, two were carried to term, whereas five were terminated. One newborn and two abortuses had congenital malformations including abnormalities of the thumb and radius. The other affected live-born infant, now 5½ years old, has severe growth retardation and pancytopenia. No Fanconi anemia-associated malformations were found in any of the other fetuses or newborns studied. In all cases in which tissue was available for study, diagnoses were confirmed by chromosome breakage studies. This method thus permits reliable detection of Fanconi anemia.

Download Full-text

Unexpected Fanconi Anemia Diagnosis in Patients with Bone Marrow Failure.

Blood ◽

10.1182/blood.v106.11.1056.1056 ◽

2005 ◽

Vol 106 (11) ◽

pp. 1056-1056

Author(s):

Fernando O. Pinto ◽

Thierry Leblanc ◽

Gwenaelle Le Roux ◽

Helene Dastot ◽

Moema Santos ◽

...

Keyword(s):

Bone Marrow ◽

Aplastic Anemia ◽

Clinical Features ◽

Fanconi Anemia ◽

Bone Marrow Failure ◽

Somatic Mosaicism ◽

Chromosome Breakage ◽

Large Set ◽

Chromosomal Breakage ◽

Group A

Abstract Early diagnosis of Fanconi Anemia (FA) in patients with bone marrow failure is critical for optimal clinical management. However, the remarkably high clinical variability and the potential emergence of revertant hematopoietic cells (somatic mosaicism) can obscure and delay the diagnosis of FA. Here we addressed FA diagnosis in a prospective series of adult and pediatric patients who presented with bone marrow failure without clear overall clinical picture of FA. Sixty-six patients were classified into three groups: (1) bone marrow failure likely to be congenital, based on dysmorphic features or a family history [n=18], (2) aplastic anemia likely to be idiopathic [n=32], (3) patients with intermediate clinical features not classified into the former groups [n=16]. Of note, FA patients with typical clinical features were not included in the present study. FA diagnosis was evaluated using chromosome breakage test and FANCD2 immunoblot in PHA-stimulated-PBL. In addition, skin primary fibroblasts were analysed in order to overcome potential hematopoietic FA reversion. For that purpose, and considering that chromosome breakage tests are barely efficient in fibroblasts, we used FANCD2 immunoblot and also developped a new flow cytometry test based on MMC-sensitivity in fibroblasts (to detect downstream FA/BRCA groups). Using these approaches, we detected FA in 4 previously undiagnosed patients: a 35-years old patient from the congenital-like group; a 10-years old patient presenting as an idiopathic aplastic anemia without any FA signs; and two patients from the intermediate group: a 10-years old patient with an isolated thrombocytopenia, and a 50-years old patient presenting with pancytopenia/MDS and complete hematopoietic reversion. Importantly, FA diagnosis was definitely excluded in all other patients. In conclusion, we could identify a few unexpected FA cases in a series of patients with bone marrow failure. Therefore, the comprehensive use of a large set of tests is useful for accurate FA diagnosis. Classical chromosomal breakage tests in PBL appeared to be sufficient to exclude FA in idiopathic aplastic anemia, whereas fibroblast analysis can be necessary to definitely diagnose or exclude FA in other patients.

Download Full-text

Sensitivity of tumor cells deficient in the fanconi anemia pathway to inhibition of ataxia telangiectasia mutated (ATM)

Journal of Clinical Oncology ◽

10.1200/jco.2007.25.18_suppl.10509 ◽

2007 ◽

Vol 25 (18_suppl) ◽

pp. 10509-10509

Author(s):

R. D. Kennedy ◽

P. Stuckert ◽

E. Archila ◽

M. De LaVega ◽

C. Chen ◽

...

Keyword(s):

Dna Damage ◽

Cell Lines ◽

Dna Damage Response ◽

Fanconi Anemia ◽

Ataxia Telangiectasia ◽

Pancreatic Head ◽

Genotoxic Stress ◽

Ataxia Telangiectasia Mutated ◽

Chromosomal Breakage ◽

Damage Response

10509 Loss of the fanconi anemia (FA) pathway function has been described in a number of sporadic tumor types including breast, ovarian, pancreatic, head and neck and hematological malignancies. Functionally, the FA pathway responds to stalled DNA replication following DNA damage. Given the importance of the FA pathway in the response to DNA damage, we hypothesized that cells deficient in this pathway may become hyper-dependent on alternative DNA damage response pathways in order to respond to endogenous genotoxic stress such as occurs during metabolism. Therefore, targeting these alternative pathways could offer therapeutic strategies in FA pathway deficient tumors. To identify new therapeutic targets we treated FA pathway competent and deficient cells with a DNA damage response siRNA library, that individually knocked out 230 genes. We identified a number of gene targets that were specifically toxic to FA pathway deficient cells, amongst which was the DNA damage response kinase Ataxia Telangiectasia Mutated (ATM). To test the requirement for ATM in FA pathway deficient cells, we interbred Fancg ± Atm± mice. Consistent with the siRNA screen result, Fancg-/- Atm-/- mice were non viable and Fancg± Atm-/- and Fancg-/- Atm ± progeny were less frequent that would have been expected. Several human cell lines with FA gene mutations were observed to have constitutive activation of ATM which was markedly reduced on correction with the appropriate wild-type FA gene. Interestingly, FA pathway deficient cells, including the FANCC mutant and FANCG mutant pancreatic cancer cell lines, were selectively sensitive to monotherapy with the ATM inhibitor KU55933, as measured by dose inhibition and colony count assays. FA pathway deficient cells also demonstrated an increased level of chromosomal breakage, cell cycle arrest and apoptosis following KU55933 treatment when compared to FA pathway corrected cells. We conclude that FA pathway deficient cells have an increased requirement for ATM activation in order to respond to sporadic DNA damage. This offers the possibility that monotherapy with ATM inhibitors could be a therapeutic strategy for tumors that are deficient for the FA pathway. No significant financial relationships to disclose.

Download Full-text

Cytoprotective effect of honey against chromosomal breakage in fanconi anemia patients in vitro

Indian Journal of Human Genetics ◽

10.4103/0971-6866.86184 ◽

2011 ◽

Vol 17 (2) ◽

pp. 77 ◽

Cited By ~ 1

Author(s):

FaezaAbdel Mogib El-Dahtory ◽

Sohier Yahia

Keyword(s):

Fanconi Anemia ◽

Cytoprotective Effect ◽

Chromosomal Breakage

Download Full-text

Diagnostic Overlap between Fanconi Anemia and the Cohesinopathies: Roberts Syndrome and Warsaw Breakage Syndrome

Anemia ◽

10.1155/2010/565268 ◽

2010 ◽

Vol 2010 ◽

pp. 1-7 ◽

Cited By ~ 22

Author(s):

Petra van der Lelij ◽

Anneke B. Oostra ◽

Martin A. Rooimans ◽

Hans Joenje ◽

Johan P. de Winter

Keyword(s):

Fanconi Anemia ◽

Bone Marrow Failure ◽

Clinical Manifestations ◽

Nijmegen Breakage Syndrome ◽

Inherited Disease ◽

Chromosomal Breakage ◽

Metaphase Chromosomes ◽

Roberts Syndrome ◽

Premature Centromere Division ◽

Multiple Symptoms

Fanconi anemia (FA) is a recessively inherited disease characterized by multiple symptoms including growth retardation, skeletal abnormalities, and bone marrow failure. The FA diagnosis is complicated due to the fact that the clinical manifestations are both diverse and variable. A chromosomal breakage test using a DNA cross-linking agent, in which cells from an FA patient typically exhibit an extraordinarily sensitive response, has been considered the gold standard for the ultimate diagnosis of FA. In the majority of FA patients the test results are unambiguous, although in some cases the presence of hematopoietic mosaicism may complicate interpretation of the data. However, some diagnostic overlap with other syndromes has previously been noted in cases with Nijmegen breakage syndrome. Here we present results showing that misdiagnosis may also occur with patients suffering from two of the three currently known cohesinopathies, that is, Roberts syndrome (RBS) and Warsaw breakage syndrome (WABS). This complication may be avoided by scoring metaphase chromosomes—in addition to chromosomal breakage—for spontaneously occurring premature centromere division, which is characteristic for RBS and WABS, but not for FA.

Download Full-text

A rare manifestation of Fanconi anemia

International Journal of Contemporary Pediatrics ◽

10.18203/2349-3291.ijcp20183547 ◽

2018 ◽

Vol 5 (5) ◽

pp. 2002

Author(s):

Pooja Pradeep ◽

Vindhiya K. ◽

Shiji R.

Keyword(s):

Fanconi Anemia ◽

Congenital Heart ◽

Autosomal Recessive ◽

Female Child ◽

Chromosomal Breakage ◽

Autosomal Recessive Form ◽

Recessive Form ◽

Rare Manifestation ◽

Hypoplastic Thumb ◽

Physical Features

Fanconi anemia is an inherited pancytopenia, primarily inherited as autosomal recessive form. It occurs in all racial and ethnic groups. Majority of patients have both physical and haematological abnormalities, about one-third of patients will have normal physical features but abnormal haematological findings and unknown percentage have physical anomalies and normal haematological findings. The diagnosis is based on characteristic physical anomalies and abnormal haematological findings, which is confirmed with a lymphocytic chromosomal breakage study using Diepoxy butane (DEB). The report here is about a two and half years old female child who presented with physical features in the form of short stature, microcephaly, left hypoplastic thumb and congenital heart disease without haematological abnormalities. Chromosomal study was suggestive of Fanconi’s anemia.

Download Full-text

International Fanconi Anemia Registry: relation of clinical symptoms to diepoxybutane sensitivity

Blood ◽

10.1182/blood.v73.2.391.bloodjournal732391 ◽

1989 ◽

Vol 73 (2) ◽

pp. 391-396

Author(s):

AD Auerbach ◽

A Rogatko ◽

TM Schroeder-Kurth

Keyword(s):

Fanconi Anemia ◽

Clinical Symptoms ◽

Clinical Manifestations ◽

Chromosomal Breakage ◽

Scoring Method ◽

Cellular Sensitivity ◽

Progressive Pancytopenia ◽

Clastogenic Effect ◽

Blood Specimens ◽

Stepwise Multivariate Logistic Regression

Fanconi anemia (FA) is characterized clinically by a progressive pancytopenia, diverse congenital abnormalities and increased predisposition to malignancy. Although a variable phenotype makes accurate diagnosis on the basis of clinical manifestations difficult in some patients, study of cellular sensitivity to the clastogenic effect of DNA cross-linking agents such as diepoxybutane (DEB) has been used to facilitate the diagnosis. Data from DEB-induced chromosomal breakage studies of 328 peripheral blood specimens from patients considered at risk for FA were analyzed using a stepwise multivariate logistic regression, in order to determine which method of representing the data best discriminated between DEB-sensitive (DEB+) and DEB-insensitive (DEB-) cases. Similar methods were applied to the data from the International Fanconi Anemia Registry (IFAR) to determine whether DEB+ and DEB- cases may be considered as distinct clinical entities, and if so, which variables provide the best discrimination between the two groups. We conclude that hypersensitivity to the clastogenic effect of DEB is a useful discriminator for FA. A simplified scoring method for classifying patients on the basis of eight clinical manifestations that are the best predictors for FA is presented. Our data indicate that the clinical diversity in FA is more widespread than previously recognized.

Download Full-text

High Incidence of Fanconi Anemia in Patients with a Morphological Picture Consistent with Refractory Cytopenia of Childhood

Blood ◽

10.1182/blood.v118.21.2780.2780 ◽

2011 ◽

Vol 118 (21) ◽

pp. 2780-2780

Author(s):

Ayami Yoshimi ◽

Charlotte M. Niemeyer ◽

Irith Baumann ◽

Stephan Schwarz-Furlan ◽

Detlev Schindler ◽

...

Keyword(s):

Bone Marrow ◽

Fanconi Anemia ◽

Conflicts Of Interest ◽

Bone Marrow Failure ◽

Test Group ◽

Clinical Feature ◽

Chromosomal Breakage ◽

Mild Phenotype ◽

European Working ◽

Chromosome Breaking

Abstract Abstract 2780 Introduction: Refractory cytopenia in childhood (RCC) is the most common subtype of myelodysplastic syndrome (MDS) in children. Differential diagnosis from inherited bone marrow failure (IBMF) such as Fanconi anemia (FA) remains an intriguing challenge, because most patients with RCC have a hypocellular bone marrow (BM) and dysplastic features in haematopoiesis are observed in both RCC and IBMF. Moreover the spectrum of phenotypic findings in FA is extremely wide. Some FA patients have a mild phenotype without malformation. The purpose of this study is to estimate the incidence of FA in an RCC cohort without a full clinical feature of FA, but subsequently diagnosed by chromosome breaking test. Patients and Methods: Between 01/2007 and 12/2010 reference pathologists of the European Working Group of MDS in Childhood (EWOG-MDS) provided a morphological report consistent with RCC in 137 children studied in Germany. Seventeen patients with hypercellular BM or abnormal karyotype, 2 patients, in whom dyskeratosis congenital was diagnosed after initial inclusion and one patient, in whom chromosome breaking test was not performed, were excluded. Results: Seven of remaining 117 patients had facial and/or skeletal anomalies typically noted in FA and one patient had a brother with FA. In these 8 patients, FA had been suspected by their local physicians (group FA-1). Nine patients (8.3%) without these typical anomalies were subsequently diagnosed of FA by chromosome breakage test (group FA-2). The diagnosis of RCC was finally made in the remaining 100 patients with negative chromosomal breakage test (group RCC). The clinical features of patients in each group are summarized in the Table. The mean corpuscular volume of red cells (MCV) was elevated (> +2SD) for ages in all patients with FA, but only 42 % in patient with RCC. In some children of group FA-2 additional non-haematological abnormalities were also observed. However, they were not evident and or typical to prompt the treating physicians to suspect FA. A few patients in the group RCC also had some physical anomalies, not specific for any of the known IBMF disorders. Possibly that other known or not yet described IBMF disorders remain uncovered in children with “de novo” RCC. Conclusion: Our results illustrate that the same haematological features and congenital anomalies can be noted in FA and RCC. More importantly, they indicate that the exclusion of FA by a chromosomal breakage test or other methods is mandatory in all patients prior to diagnosis RCC. Chromosomal breakage analysis may identify patients with FA in 8% of patients with a morphological description of RCC without a full clinical picture of FA. Disclosures: No relevant conflicts of interest to declare.

Download Full-text