Monica Bessler, MD, PhD

Monica Bessler, MD, PhD, is a pediatric hematologist and director of the Bone Marrow Failure Center at The Children's Hospital of Philadelphia. Dr. Bessler is also the Buck Family Endowed Chair in Hematology.

Locations: Main Campus
Appointments and Referrals: 1-800-TRY-CHOP (1-800-879-2467)

  • Background

    Dr. Bessler is currently the Director of The Pediatric and Adult Comprehensive Bone Marrow Failure Center at the Children’s Hospital of Philadelphia and the Perelman School of Medicine University of Pennsylvania Health System in Philadelphia, PA.

    Prior to her current position, she was Professor in Internal Medicine and Professor in Molecular Biology and Pharmacology at Washington University School of Medicine in St. Louis, MO.

    Dr. Bessler received a physician’s degree from the Medical School of the University of Zurich, Switzerland in 1981 and her medical degree from University of Basel, Switzerland in 1984. Then, in 1994, she received a PhD in genetics from the University of London. She is board certified in Internal Medicine and Hematology.

    Her clinical interests include acquired and inherited bone marrow failure, paroxysmal nocturnal hemoglobinuria, dyskeratosis congenita, Diamond Blackfan anemia, Shwachman Diamond syndrome and familial aplastic anemia and myelosdysplastic syndromes (MDS). Furthermore Dr. Bessler has a special interest in pediatric-adult transition for patients with bone marrow failure. She sees pediatric and adult patients and is interested in determining the adult manifestation and treatment of diseases that usually occurs in childhood as well as determining the early clinical signs in children with bone marrow failure conditions that usually only become obvious in the adult.

    Outside the clinic her laboratory research aims to define the molecular mechanisms that cause bone marrow failure and the factors that determine the clinical outcome and response to treatment. Bone marrow failure (BMF) is the inability of the bone marrow to produce sufficient blood cells. BMF may be brought about by a number of causes. These may be genetic (inherited bone marrow failure syndromes, IBMFS) or acquired. BMF may affect all, or only individual blood cell lineages. The aims of her research are a) to develop more specific tests or biomarkers that distinguish and diagnose individual forms of BMF, b) to identify the pathways that lead to BMF, c) to characterize the pathways responsible for late complications, such as the development of myelodysplastic syndrome (MDS) and leukemia, and finally d) to investigate specific and more targeted treatments for patients with BMF, allowing personalized therapy for patients with problems in blood cell production.

  • Education and Training

    Medical School

    MD - University of Zurich, Zurich Switzerland


    Clinical Pathology - Kantonspital St. Gallen, University of Basel, Basel, Switzerland
    Internal Medicine - Hospital Waid, Zurich University of Zurich, Zurich, Switzerland
    Internal Medicine - Hospital Triemli, Zurich, University of Zurich, Zurich, Swi


    Research fellow in Clinical Hematology - Department of Hematology, University Hospital of Zurich, Zurich, Switzerland
    Research fellow in Clinical Genetics - Institute for Clinical Genetics, University of Zurich, Zurich, Switzerland
    Research fellow in Hematology - Royal Postgraduate Medical School, Hammersmith Hospital, London, England

    Additional Training

    Research Associate - Department of Human Genetics, Memorial Sloan-Kettering Cancer Center, New York, NY

    Board Certification

    Internal medicine

    Graduate Degree

    PhD in Genetics - University of London, London, UK

  • Titles and Academic Titles

    Attending Hematologist

    Director, Comprehensive Bone Marrow Failure Center

    Buck Family Endowed Chair in Hematology

    Professor of Pediatrics, Perelman School of Medicine at the University of Pennsylvania
    Professor of Internal Medicine, Perelman School of Medicine at the University of Pennsylvania

  • Departments and Services
  • Publications



    Babushok DV and Bessler M. Anemia: Pathophysiology, Diagnosis and Management. Edited by Edward J. Benz, Nancy Berliner and Fred J. Schiffman. Cambridge University Press. 2014 in Press.

    Bessler M, Mason PJ, Link DC, Wilson DB. Inherited Bone Marrow Failure Syndromes. In: Orkin, SH Ginsburg, D, Nathan DG, Look, AT, Fisher, DE, Lux, SE, eds. Nathan’s and Oski’s Hematology of Infancy and Childhood. 8th edition. Philadelphia: W.B. Saunders Co; 2014. In press



    Bessler M, Mason PJ, Link DC, Wilson DB. Inherited bone marrow failure syndromes. In: Orkin, SH Ginsburg, D, Nathan DG, Look, AT, Fisher, DE, Lux, SE, editors. Nathan’s and Oski’s hematology of infancy and childhood. 7th ed. Philadelphia: W.B. Saunders Co; 2008. p. 307-395.

    Du HY, Bessler M, Mason PJ. Telomerase mutations and premature ageing in humans. In: Rudolf KL, editor. Telomeres and telomerase in aging, disease, and cancer. New York: Springer; 2008. p. 77-107. 


    Bessler M, Kulkarni S, Jasinski M, Schaefer A, Keller P, Tremml G. Mice with blood cells deficient in GPI-linked proteins — the generation of a murine model to investigate the pathogenesis and pathophysiology of paroxysmal nocturnal hemoglobinuria (PNH). Proceedings of the International Symposium on paroxysmal nocturnal hemoglobinuria and related disorders. Tokyo (Japan): Springer-Verlag; 2003. p. 27-40. 


    Bessler M, Atkinson JP. Paroxysmal nocturnal hemoglobinuria (PNH). In: Stamatoyannopoulos, A. Nienhuis, P. Majerus, H. Varmus, editors. The molecular basis of blood diseases. 2nd ed. Philadelphia: W. B. Saunders Company; 2000. p. 564-79.

    Kinoshita T, Bessler M, Takeda J. Animal models of paroxysmal nocturnal hemoglobinuria. In: Paroxysmal nocturnal hemoglobinuria and the glycophosphoinositol-linked proteins. London: Academic Press; 2000. p. 139-55.



    Gu BW, Apicella M, Mills J, Fan JM, French D, Podsakoff GM, Bessler M, Mason PJ. Impaired telomere maintenance and decreased canonical WNT signaling but normal ribosome biogenesis in induced pluripotent stem cells from X-linked dyskeratosis congenita patients. PLOS 2015. In press.

    Babushok DV, Perdigones, N, Perinc, JC, Olson TS, Yeb, W, Roth, JJ, Lind,C , Cattier C, Li Y, Hartung H, Paessler, ME, Frank, DM, Xie HM, Shanna, C, Cockroft JD, Podsakoff, GM, Monos, D, Biegel, JA, Philip J. Mason, PJ, Bessler, M. Emergence of Clonal Hematopoiesis in the majority of Patients with Acquired Aplastic Anemia. Cancer Genetics 2015. In press. PMID: 25800665 NIHMSID 660724.


    Schrezenmeier H, Muus P, Socié G, Szer J, Urbano-Ispizua A, Maciejewski JP, Brodsky RA, Bessler M, Kanakura Y, Rosse W, Khursigara G, Bedrosian C, Hillmen P. Baseline characteristics and disease burden in patients in the international paroxysmal nocturnal hemoglobinuria registry. Haematologica. 2014 May;99(5):922-9. PMID: 24488565, PMCID: PMC4008114.

    Pesciotta EN, Sriswasdi S, Tang HY, Speicher DW, Mason PJ, Bessler M. Dysferlin and other non-red cell proteins accumulate in the red cell membrane of diamond-blackfan anemia patients. PLoS One. 2014 Jan 14;9(1):e85504. doi: 10.1371/journal.pone.0085504. PMID:24454878; PMCID: PMC3891812.


    Williams D.A, Bennett C, Bertuch A, Bessler M, Coates T, Corey S, Dror Y, Huang J, Lipton J, Olson TS, Reiss UM, Rogers ZR, Sieff C, Vlachos A, Walkovich K, Wang W, Shimamura A. Diagnosis and treatment of pediatric acquired aplastic anemia (AAA): an initial survey of the north american pediatric aplastic anemia consortium (NAPAAC). Pediatric Blood & Cancer 2013, in press. PMCID: PMC3714320

    Babushok, D.V., Xie, H.M., Roth, J.J., Perdigones, N., Olson, T.S., Cockroft, J.D., Gai, X., Perin, J.C., Li, Y., Paessler, M.E., Hakonarson, H., Podsakoff, G.M., Mason, P.J., Biegel, J.A. and Bessler, M. Single nucleotide polymorphism analysis of bone marrow failure patients reveals characteristic patterns of genetic changes, Br. J. Haematology, 2013, 2013,88 (10) 862-867. PMID:24116929; PMCID: PMC3986350.

    Babushok DV, Li Y, Roth JJ, Perdigones N, Cockroft JD, Biegel JA, Mason JP, Bessler M. Common Polymorphic Deletion of Glutathione S-Transferase Theta Predisposes to Acquired Aplastic Anemia: Independent Cohort and Meta-Analysis of 609 Patients. American Journal of Hematology. 2013 in press. PMID:23798465; PMCID: PMC3983712.

    Garcon L, Ge JP, Manjunath S, Mills J, Apicela M, Parikh S, Sullivan L, Podsakof G, Gadue P, French D, Mason PJ, Bessler M, Weiss M. Ribosomal and Hematopoietic Defects in Induced Pluripotent Stem Cells Derived From Diamond Blackfan Anemia Patients. Blood. 2013 122(6):912-921. PMID:23744582; PMCID:PMC3739037.

    Gu BW, Ge JP, Fan JM, Bessler M, Mason JP. Slow growth and unstable ribosomal RNA lacking pseudouridine in mouse embryonic fibroblasts cells expressing catalytically inactive dyskerin. FEBS Letters. 2013, 587(14):2112-2117. PMID:23726835; PMCID:PMC3773870.

    Olson TS, Chan ES, Paessler ME, Frantz CN, Sullivan K, Russo P, and Bessler M. Liver failure due to hepatic angiosarcoma in an adolescent with dyskeratosis congenita. Journal of Pediatric Hematology and Oncology 2013. In press. PMID:23588325; PMCID:PMC3714320

    Vogiatzi P, Perdigones N Mason PJ, Wilson DB Bessler M. A family with Hoyeraal-Hreidarsson syndrome and four variants in two genes of the telomerase core complex. Pediatric Blood & Cancer 2013 60(6):E4-6. doi: 10.1002/pbc.24389. PMID: 23335200. PMCID: PMC3860171. 

    Posters and Presentations

    Invited Lectures


    Paroxysmal Nocturnal Hemoglobinuria (PNH), National Organization for Rare Disorders, White Plane, NY, October 2014.

    “Paroxysmal Nocturnal Hemoglobinuria” Bone Marrow Failure Disease Symposium Washington University Medical Center St. Louis, Missouri, October 2014.

    “Pediatric Adult Transition” Dyskeratosis outreach. Camp Sunshine Portland, ME, October 2014.

    Key Note Speacker. Bone Marrow Failure Disease Symposium at Hershey. “Towards Precision Medicine in BMF”, September 2014.

    “Pediatric Adult Transition” Shwachman Diamond Syndrome Foundation. Camp Sunshine Portland, ME, September 2014.

    Scientific Program Guest Speaker. Institute for Research in Immunology and Cancer, IRIC-Université de Montréal, CANADA “A systems biology approach to bone marrow failure”, March 2014.

    Keynote Speaker, K12 Clinical Hematology Research Scholars Symposium University of Pennsylvania & The Children’s Hospital of Philadelphia. “Following your Passion as a Career Development Plan", May 2014.

    New Directions in PNH: What's on the Horizon? 2014 Regional Conference: PNH: Current Thinking on the Disease, Diagnosis, and Treatment. Philadelphia PA, May 2014.

    Aplastic Anemia, MDS and PNH. 2014 Regional Conference: PNH: Current Thinking on the Disease, Diagnosis, and Treatment. Philadelphia PA, May 2014.

    Keynote Speaker, 10th Annual Texas Children’s Cancer and Hematology Centers, Research Symposium, Huston TX. “Toward Precision Medicine in Bone Marrow Failure”, May 2014.


    Paroxysmal Nocturnal Hemoglobinuria (PNH), National Organization for Rare Disorders, Philadelphia, PA, October 2013.

    Using IPCs for the investigation of X-linked dyskeratosis congenita. Telomeres and Disease, Banbury Center of Cold Spring Harbor Laboratory, September 2013.

    Turning Skin into Blood for DBA: What does the IPSC technology mean for DBA. Portland Main, July 2013.

    Paroxysmal Nocturnal Hemoglobinuria (PNH), National Organization for Rare Disorders, Austin, TX, February 2013.

  • Awards and Honors

    2011, Presidential Lecture at the 53rd Meeting of the America Society of Hematology
    2005, Hematology Faculty F1000 Medicine
    2003, Bursary Award from the Aplastic Anemia & Myelodysplastic Syndrome International Foundation
    2000-2002, Edward Mallinckrodt, Jr. Foundation Award
    1998-2000, Junior Faculty Award, American Society of Hematology
    1997-2000, James S. McDonnell Fellowship
    1995, Ellermann Prize
    1991-1994, Weston Scholarship, London UK
    1991-1994, Overseas Research Students Award, UK
    1991-1993, Fellowship of Walter Honegger Stiftung, Zurich, Switzerland
    1990, Prize of the Swiss Society of Hematology

  • Editorial and Academic Positions

    Editorial Positions

    2008-present, Clinical and Translational Science (CTS), editorial board
    2005-present, F1000 Medicine, faculty member


    New England Journal of Medicine
    Nature Medicine
    The EMBO Journal
    The Journal of Clinical Investigation
    Experimental Hematology
    Brit. Journal of Haematology
    Molecular & Cellular Biology
    Developmental Biology
    Journal of Laboratory Investigation
    Leukocyte Biology

    Academic and Institutional Committees

    2012-present, Clinical Hematology and Transfusion Medical Research Career Development Program (K12) University of Pennsylvania, co-director

  • Leaderships

    Memberships in Professional Organizations


    1997-present, European Society of Haematology
    1994-present, British Genetics Society


    2007-present, Association of American Physicians
    2003-present, American Society of Clinical Investigations
    1994-present, American Society of Hematology