Fanconi anemia laboratory findings: Difference between revisions
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==Overview== | ==Overview== | ||
The laboratory findings in Fanconi anemia include decreased hemoglobin on CBC and increased chromosomal breakage with mitomycin C or diepoxybutane. There may also be single-lineage or multi-lineage cytopenias. <ref name="pmid8502512">{{cite journal| author=Giampietro PF, Adler-Brecher B, Verlander PC, Pavlakis SG, Davis JG, Auerbach AD| title=The need for more accurate and timely diagnosis in Fanconi anemia: a report from the International Fanconi Anemia Registry. | journal=Pediatrics | year= 1993 | volume= 91 | issue= 6 | pages= 1116-20 | pmid=8502512 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=8502512 }}</ref> Flow cytometry of hematopoietic cells may show cell cycle arrest in G2/M phase. | |||
The | |||
==Laboratory Findings== | ==Laboratory Findings== | ||
=== Complete blood count (CBC) === | |||
In Fanconi anemia, the complete blood count (CBC) may reveal trilineage pancytopenia or may only show RBCs that are macrocytic for age. Macrocytosis, thrombocytopenia, and/or leukopenia may precede full-blown aplasia. | In Fanconi anemia, the complete blood count (CBC) may reveal trilineage pancytopenia or may only show RBCs that are macrocytic for age. Macrocytosis, thrombocytopenia, and/or leukopenia may precede full-blown aplasia. | ||
=== | === Chromosomal breakage test === | ||
Chromosome breakage is usually examined in short-term cultures of peripheral blood T | *Chromosome breakage is usually examined in short-term cultures of peripheral blood mitogen–stimulated T lymphocytes in the presence of DNA cross-linkers, such as diepoxybutane (DEB) or mitomycin C (MMC).<ref name="pmid85005732">{{cite journal| author=Auerbach AD| title=Fanconi anemia diagnosis and the diepoxybutane (DEB) test. | journal=Exp Hematol | year= 1993 | volume= 21 | issue= 6 | pages= 731-3 | pmid=8500573 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=8500573 }}</ref> These agents lead to increased numbers of breaks, gaps, rearrangements, and quadraradii in Fanconi anemia homozygote cells. It is considered as screening test for Fanconi anemia. | ||
*Some patients may have hematopoietic somatic mosaicism, with correction of the Fanconi anemia defect in the blood. In these cases, skin fibroblasts may be needed for the chromosome breakage test. | |||
Some patients may have hematopoietic somatic mosaicism, with correction of the Fanconi anemia defect in the blood. In these cases, skin fibroblasts may be needed for the chromosome breakage test. | * FA gene sequencing is generally suggested for all patients with a positive result from chromosomal breakage testing. The reason is that identification of the genetic defect definitively confirms the diagnosis and eliminates other chromosomal breakage disorders as the cause of the abnormal screening test. Furthermore, sequencing allows screening of family members for the purposes of identifying HCT donors, performing prenatal testing, and genetic counseling, given that heterozygous carriers will not have abnormal chromosomal breakage analysis. | ||
=== Flow cytometry === | === Flow cytometry === | ||
Flow cytometry of Fanconi anemia cells cultured with nitrogen mustard and other clastogens demonstrates an arrest in G2/M. | Flow cytometry of Fanconi anemia cells cultured with nitrogen mustard and other clastogens demonstrates an arrest in G2/M. Flow cytometry for cell cycle analysis can be performed through propidium iodide staining, Hoechst staining, or pyronin Y staining. | ||
==References== | ==References== | ||
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Shyam Patel [2]
Overview
The laboratory findings in Fanconi anemia include decreased hemoglobin on CBC and increased chromosomal breakage with mitomycin C or diepoxybutane. There may also be single-lineage or multi-lineage cytopenias. [1] Flow cytometry of hematopoietic cells may show cell cycle arrest in G2/M phase.
Laboratory Findings
Complete blood count (CBC)
In Fanconi anemia, the complete blood count (CBC) may reveal trilineage pancytopenia or may only show RBCs that are macrocytic for age. Macrocytosis, thrombocytopenia, and/or leukopenia may precede full-blown aplasia.
Chromosomal breakage test
- Chromosome breakage is usually examined in short-term cultures of peripheral blood mitogen–stimulated T lymphocytes in the presence of DNA cross-linkers, such as diepoxybutane (DEB) or mitomycin C (MMC).[2] These agents lead to increased numbers of breaks, gaps, rearrangements, and quadraradii in Fanconi anemia homozygote cells. It is considered as screening test for Fanconi anemia.
- Some patients may have hematopoietic somatic mosaicism, with correction of the Fanconi anemia defect in the blood. In these cases, skin fibroblasts may be needed for the chromosome breakage test.
- FA gene sequencing is generally suggested for all patients with a positive result from chromosomal breakage testing. The reason is that identification of the genetic defect definitively confirms the diagnosis and eliminates other chromosomal breakage disorders as the cause of the abnormal screening test. Furthermore, sequencing allows screening of family members for the purposes of identifying HCT donors, performing prenatal testing, and genetic counseling, given that heterozygous carriers will not have abnormal chromosomal breakage analysis.
Flow cytometry
Flow cytometry of Fanconi anemia cells cultured with nitrogen mustard and other clastogens demonstrates an arrest in G2/M. Flow cytometry for cell cycle analysis can be performed through propidium iodide staining, Hoechst staining, or pyronin Y staining.
References
- ↑ Giampietro PF, Adler-Brecher B, Verlander PC, Pavlakis SG, Davis JG, Auerbach AD (1993). "The need for more accurate and timely diagnosis in Fanconi anemia: a report from the International Fanconi Anemia Registry". Pediatrics. 91 (6): 1116–20. PMID 8502512.
- ↑ Auerbach AD (1993). "Fanconi anemia diagnosis and the diepoxybutane (DEB) test". Exp Hematol. 21 (6): 731–3. PMID 8500573.