FANCA Gene in Pakistani Fanconi Anemia Patients: Screening of Mutations in Exon 28 and Exon 29

Objective: This kind of study was conducted first time in Pakistan. Its objective was to ascertain the associated clinical features and analyze the FANCA exon 28 and exon 29 mutations in Pakistani Fanconi anemia (FA) patients. Methods: A total of 38 patients with Fanconi anemia were recruited presenting in the Armed forces institute of pathology (AFIP) Rawalpindi Pakistan. They were enrolled in this study on the basis of comprehensive clinical evaluation and positive Diepoxybutane (DEB)/Mitomycin C Chromosomal breakage test. Genomic DNA was extracted from peripheral blood of patients and age and gender-matched controls. Mutation analysis of FANCA gene was done by conventional Polymerase chain reaction (PCR) and DNA sequencing. Various online tools and software were used for analysis of the obtained data and identification of the sequence alterations in FANCA gene in exon 28 and exon 29 of FA patients. Results and Discussion: The current study on screening of FANCA mutational analysis in exon 28 and exon 29 revealed four novel mutations. These include three missense variants (p.F876L, p.L883H, and p.K921I) in exon 28 and a novel homozygous frameshift variant (p.S947FfsX950) in exon 29. In addition two new intronic variants were also found in this set of patients. Conclusion: The sequence variants identified in this study in 10 (26.31%) FA patients in two out of forty-three FANCA gene exons (i.e., exon 28 and exon 29) strongly emphasize the importance of large-scale molecular studies on FANCA gene in Pakistani population.

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

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 percent). In 2 patients (2.4 percent), there was an absence of both the monoubiquitinated and the non-ubiquitinated proteins (FANCD2S-/FANCD2L-) and 5 patients (5.9 percent) 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 percent (79/84) and specificity of 100 percent (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.

Chromosome Breakage Test for the Diagnosis of Fanconi's Anemia / 대한임상병리학회지

BACKGROUND: Fanconi's anemia (FA) is an autosomal recessive disease characterized by aplastic anemia, pre-malignancy, congenital malformations and chromosome breakage syndromes. As up to 30% of patients have no detectable congenital anomalies, the modern diagnosis of FA rests on chromosomal breakage of patient's cells induced by chemical clastogens such as diepoxybutane (DEB) or mitomycin-C (MMC). METHODS: We have done chromosome breakage test to differentiate FA from 11 aplastic anemia, three Diamond-Blackfan syndrome, three myelodysplastic syndrome, one acute leukemia with congenital anomaly and three siblings of FA. The peripheral blood lymphocytes from each individual were co-cultured in phytohemagglutinin-containing medium by the three methods, i.e., DEB treated, MMC treated and un-treated. RESULTS: Five cases were found to have increased chromosomal breakages to DEB and MMC, confirming diagnosis of FA. Other 21 cases showed no increased chromosomal breakages. No overlap was found between FA group and others (P<0.01). In one FA, there was no increased spontaneous breakage, but increased breakage to DEB and MMC. Of five FA, one case showed no congenital anomalies. CONCLUSIONS: Chromosme breakage test was shown to be simple, reliable and useful in ascertaining the diagnosis of FA.

A Clinical Study of Fanconi's Anemia / 대한소아혈액종양학회지

BACKGROUND: Fanconi's anemia(FA) is an autosomal recessive disease characterized by aplastic anemia and congenital malformations. As up to 30% of patients have no physical stigmata, the modern diagnosis of FA rests on chromosomal breakage of patient's cells induced by chemical clastogens such as diepoxybutane(DEB) or mitomycin-C(MMC). METHODS: We reviewed the clinical manifestations, laboratory findings, diagnostic methods, treatment and outcome of 6 patients diagnosed to have a FA at the Chonnam University Hospital for the last 6 years. RESULTS: Six cases(16.2 %) were found to have FA among 37 aplastic children who were diagnosed during the same period. The mean age at diagnosis was 6.3 years which was the usual onset of hematologic findings. All patients had features of aplastic anemia, and had one or more anomalies, such as low birth weight, hyperpigmentation, cafeau-lait spots, mental retardation, developmental delay, peculiar face(broad nasal bases, epicanthal folds, micrognathia), polydactyly, microcephaly, short stature, and dislocation of hip. We found increased breaks in cultured cells with DEB and MMC in 5 cases tested. The median duration of follow-up was 30 months. Oxymetholone and prednisolone treatment was partially beneficial in three cases. Immunosuppressive treatment with ALG/ATG was not successful in two cases tried. Four cases are living now, without transfusion in three. Two patients were died of disseminated fungal infection and transplant-related problems, respectively. CONCLUSIONS: Fanconi's anemia should be sought carefully in any patients with aplastic anemia because the prognosis, treatment modality, and the approach to bone marrow transplantation are quite different when the hematologic disorder is inherited rather than acquired.