Detection of somatic mosaicism and classification of Fanconi anemia patients by analysis of the FA/BRCA pathway

Soulier, Jean; Leblanc, Thierry; Larghero, Jérôme; Dastot, Hélène; Shimamura, Akiko; Guardiola, Philippe; Esperou, Hélène; Ferry, C; Jubert, Charlotte; Feugeas, Jean-Paul; Henri, A; Toubert, Antoine; Socié, Gérard; Baruchel, André; Sigaux, François; D’Andrea, Alan D.; Gluckman, Éliane

doi:10.1182/blood-2004-05-1852

Cited by 124 publications

(133 citation statements)

References 38 publications

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“…Western blot for BRCA2 as well as Ponceau staining were performed to exclude protein degradation on samples that showed absence of both isoforms (FANCD2S-/FANCD2L-). These data are similar to those of Soulier et al (33) who found absence of FANCD2 bands in 5.7% FA patients. This phenotype suggests mutations on FANCD2 that may either alter its level of expression or result on a dysfunctional protein.…”

Section: Chromosome Breakage Test -Diepoxybutanesupporting

confidence: 82%

“…This result is in agreement with worldwide data showing that complementation groups of the core complex represents more than 90% of the cases (20,21). Soulier et al (33) identified this phenotype in 89% of the patients (47 of 53) by FANCD2 Western blot on PBLs and on skin fibroblasts.…”

Section: Resultsmentioning

confidence: 99%

“…Despite the suggestion of a milder phenotype in these patients, reversion is frequently associated with bone marrow failure and leukemia (39). The presence of a significant number of reverted cells can mask FA diagnostic tests giving ambiguous or false-negative results (33,40). Somatic mosaicism can hide mutations on FANCD2 itself or on…”

Section: Chromosome Breakage Test -Diepoxybutanementioning

confidence: 99%

“…This test is based on the Western blot for FANCD2 where both isoforms of this central protein (monoubiquitinated and non-ubiquitinated) can be distinguished. Furthermore, Soulier et al (33) proposed an evaluation strategy to detect functional reversion in peripheral blood lymphocytes (PBLs) and to classify FA patients. These investigators showed that comparison of fibroblasts and PBLs using FANCD2 Western blots permits the detection of somatic mosaicism.…”

Section: Introductionmentioning

confidence: 99%

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FANCD2 Western blot as a diagnostic tool for Brazilian patients with Fanconi anemia

Pilonetto

Pereira

Bitencourt

et al. 2009

Braz J Med Biol Res

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Fanconi anemia is a rare hereditary disease showing genetic heterogeneity due to a variety of mutations in genes involved in DNA repair pathways, which may lead to different clinical manifestations. Phenotypic variability makes diagnosis difficult based only on clinical manifestations, therefore laboratory tests are necessary. New advances in molecular pathogenesis of this disease led researchers to develop a diagnostic test based on Western blot for FANCD2. The objective of the present study was to determine the efficacy of this method for the diagnosis of 84 Brazilian patients with Fanconi anemia, all of whom tested positive for the diepoxybutane test, and 98 healthy controls. The FANCD2 monoubiquitinated isoform (FANCDS+/FANCD2L-) was not detected in 77 patients (91.7%). In 2 patients (2.4%), there was an absence of both the monoubiquitinated and the non-ubiquitinated proteins (FANCD2S-/FANCD2L-) and 5 patients (5.9%) had both isoforms (FANCD2S+/FANCD2L+). This last phenotype suggests downstream subtypes or mosaicism. All controls were diepoxybutane negative and were also negative on the FANCD2 Western blot. The Western blot for FANCD2 presented a sensitivity of 94% (79/84) and specificity of 100% (98/98). This method was confirmed as an efficient approach to screen Brazilian patients with deleterious mutations on FANCD2 (FANCD2S-/FANCD2L-) or other upstream genes of the FA/BRCA pathway (FANCDS+/FANCD2L-), to confirm the chromosome breakage test and to classify patients according to the level of FA/BRCA pathway defects. However, patients showing both FANCD2 isoforms (FANCD2S+/FANCD2L+) require additional studies to confirm mutations on downstream Fanconi anemia genes or the presence of mosaicism.

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Section: Chromosome Breakage Test -Diepoxybutanesupporting

confidence: 82%

Section: Resultsmentioning

confidence: 99%

Section: Chromosome Breakage Test -Diepoxybutanementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

FANCD2 Western blot as a diagnostic tool for Brazilian patients with Fanconi anemia

Pilonetto

Pereira

Bitencourt

et al. 2009

Braz J Med Biol Res

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“…It is therefore possible for one allele to act as a template for homologous recombination, allowing the other allele to be repaired. If this process occurs during embryonic development, it results in a mosaic individual in which some cells are Fanconi-deficient while others will be Fanconi-competent [66,67]. Although a compelling argument somatic mosacism does not explain the variability of the FA phenotype.…”

Section: Fa Is Genetically Complexmentioning

confidence: 99%

The Fanconi anaemia pathway orchestrates incisions at sites of crosslinked DNA

Crossan

Patel

2011

The Journal of Pathology

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Fanconi anaemia (FA) is a rare, autosomal recessive, genetically complex, DNA repair deficiency syndrome in man. Patients with FA exhibit a heterogeneous spectrum of clinical features. The most significant and consistent phenotypic characteristics are stem cell loss, causing progressive bone marrow failure and sterility, diverse developmental abnormalities and a profound predisposition to neoplasia. To date, 15 genes have been indentified, biallelic disruption of any one of which results in this clinically defined syndrome. It is now apparent that all 15 gene products act in a common process to maintain genome stability. At the molecular level, a fundamental defect in DNA repair underlies this complex phenotype. Cells derived from FA patients spontaneously accumulate broken chromosomes and exhibit a marked sensitivity to DNA-damaging chemotherapeutic agents. Despite complementation analysis defining many components of the FA DNA repair pathway, no direct link to DNA metabolism was established until recently. First, it is now evident that the FA pathway is required to make incisions at the site of damaged DNA. Second, a specific component of the FA pathway has been identified that regulates nucleases previously implicated in DNA interstrand crosslink repair. Taken together, these data provide genetic and biochemical evidence that the FA pathway is a bona fide DNA repair pathway that directly mediates DNA repair transactions, thereby elucidating the specific molecular defect in human Fanconi anaemia.

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