Abdul Mannan: Normal Blood DEB Test Does Not Always Rule Out Fanconi Anaemia
Abdul Mannan, Consultant Haematologist at Betsi Cadwaladr University Health Board, shared a post on LinkedIn about articles, published in American Journal of Hematology, adding:
“A normal blood DEB test does not always rule out Fanconi anaemia.
That is a high-yield trap in inherited marrow failure.
A child may have short stature, café-au-lait pigmentation, macrocytosis and progressive pancytopenia.
Yet peripheral-blood DEB/MMC chromosome-fragility testing can be normal.
Why?
- Somatic reversion can restore DNA cross-link repair in some blood-cell clones
- Those revertant cells can dilute the abnormal chromosome-breakage signal
- The blood result may therefore look reassuring when it should not be
What should you do when the phenotype still points to Fanconi anaemia?
- Repeat DEB or MMC chromosome-breakage testing using cultured skin fibroblasts
- Pair this with germline molecular testing, ideally from fibroblast DNA if mosaicism is suspected
- If fibroblast testing is negative, reconsider other inherited marrow-failure disorders
The practical lesson: test the tissue that is least likely to have been ‘rescued’ by a revertant blood-cell clone.
This approach is supported by paediatric marrow-failure guidance and reports of reverse mosaicism masking blood DEB findings.
Would a negative blood DEB assay ever stop your FA work-up?”
Title: Diagnostic work-up for severe aplastic anemia in children: Consensus of the North American Pediatric Aplastic Anemia Consortium
Authors: Kristin A Shimano, Anupama Narla, Melissa J Rose, Nicholas J Gloude, Steven W Allen, Katie Bergstrom, Larisa Broglie, Beth A Carella, Paul Castillo, Jill L O de Jong, Yigal Dror, Amy E Geddis, James N Huang, Bonnie W Lau, Catherine McGuinn, Taizo A Nakano, Kathleen Overholt, Jennifer A Rothman, Anjali Sharathkumar, Evan Shereck, Adrianna Vlachos, Timothy S Olson, Alison A Bertuch, Marcin W Wlodarski, Akiko Shimamura, Jessica Boklan

Title: Natural gene therapy by reverse mosaicism leads to improved hematology in Fanconi anemia patients
Authors: María José Ramírez, Roser Pujol, Juan Pablo Trujillo-Quintero, Jordi Minguillón, Massimo Bogliolo, Paula Río, Susana Navarro, José A Casado, Isabel Badell, Estela Carrasco, Judith Balmaña, Albert Català, Julián Sevilla, Cristina Beléndez, Bienvenida Argilés, Mónica López, Cristina Díaz de Heredia, Gayatri Rao, Eileen Nicoletti, Jonathan D Schwartz, Juan A Bueren, Jordi Surrallés

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