Alexa Siddon, MD
Professor of Laboratory MedicineCards
About
Research
Publications
2026
Leukocytosis and a JAK2 mutation: The importance of expertise in somatic variant interpretation
Puzo C, Hager K, Rose M, Wong E, Tormey C, Siddon A. Leukocytosis and a JAK2 mutation: The importance of expertise in somatic variant interpretation. Leukemia Research Reports 2026, 25: 100563. PMID: 41626141, PMCID: PMC12854866, DOI: 10.1016/j.lrr.2026.100563.Peer-Reviewed Original ResearchThis study investigates a rare JAK2 mutation in a patient with eosinophilia, demonstrating its likely benign nature and emphasizing the importance of expert interpretation in genetic testing for accurate diagnosis.
2025
ASCP Board of Certification Survey of Medical Laboratory Science education 2023: faculty
Duzan D, Fong K, Freeman V, Goodyear N, Nadder T, Siddon A, Spiczka A, Taff T, Tanabe P. ASCP Board of Certification Survey of Medical Laboratory Science education 2023: faculty. Lab Medicine 2025, 57: lmaf073. PMID: 41441795, DOI: 10.1093/labmed/lmaf073.Peer-Reviewed Original ResearchJoining the National Resident Matching Program Fellowship Match: the hematopathology experience
Courville E, Seifert R, Sadigh S, Chen X, Calli J, Hasserjian R, Siddon A. Joining the National Resident Matching Program Fellowship Match: the hematopathology experience. Academic Pathology 2025, 13: 100230. PMID: 41488033, PMCID: PMC12756700, DOI: 10.1016/j.acpath.2025.100230.Peer-Reviewed Original ResearchThis study investigates the impact of hematopathology fellowships joining the National Resident Matching Program, showing improved applicant-program matching rates and satisfaction for both parties in 2025.ASCP Board of Certification survey of Medical Laboratory Science education 2023: programs
Duzan D, Fong K, Freeman V, Goodyear N, Nadder T, Siddon A, Spiczka A, Taff T, Tanabe P. ASCP Board of Certification survey of Medical Laboratory Science education 2023: programs. Lab Medicine 2025, 57: lmaf069. PMID: 41273160, DOI: 10.1093/labmed/lmaf069.Peer-Reviewed Original ResearchASCP Board of Certification survey of Medical Laboratory Technician education 2023: faculty and programs
Duzan D, Fong K, Freeman V, Goodyear N, Nadder T, Siddon A, Spiczka A, Taff T, Tanabe P. ASCP Board of Certification survey of Medical Laboratory Technician education 2023: faculty and programs. Lab Medicine 2025, 57: lmaf071. PMID: 41240385, DOI: 10.1093/labmed/lmaf071.Peer-Reviewed Original ResearchHypomethylating Agent and Venetoclax Combination Is a Safe and Effective Alternative to Intensive Chemotherapy in Older (≥ 70 Years) Patients With Newly Diagnosed Favorable Risk Acute Myeloid Leukemia
Ball S, Jain A, Al Ali N, Aguirre L, Bewersdorf J, Kent A, Rose A, Hayden A, Siddon A, Lykon J, Madarang E, Swoboda D, Padron E, Sweet K, Sallman D, Lancet J, Carraway H, Watts J, Zeidan A, Pollyea D, Komrokji R. Hypomethylating Agent and Venetoclax Combination Is a Safe and Effective Alternative to Intensive Chemotherapy in Older (≥ 70 Years) Patients With Newly Diagnosed Favorable Risk Acute Myeloid Leukemia. American Journal Of Hematology 2025, 100: 1920-1923. PMID: 40772639, DOI: 10.1002/ajh.70031.Commentaries, Editorials and LettersHeterogeneity in outcomes of TP53‐mutated myeloproliferative neoplasms based on disease phenotype and mutational status
Badar T, Foran J, Bewersdorf J, Wang Y, Coltoff A, Kettani M, Shah K, Oliva F, Lin C, Jamy O, Diebold K, Shallis R, Siddon A, Katkov D, Schoen A, Khan I, Foucar C, Atallah E, Goldberg A, Patel A. Heterogeneity in outcomes of TP53‐mutated myeloproliferative neoplasms based on disease phenotype and mutational status. British Journal Of Haematology 2025, 207: 683-686. PMID: 40400334, DOI: 10.1111/bjh.20187.Commentaries, Editorials and LettersAssessing AML-based risk criteria in patients with accelerated/blast-phase MPN treated with less-intensive therapy
Shaw R, Yoon J, Johnston H, Davidson M, Siddon A, Shallis R, Chen E, Burkart M, Oh T, Iyer S, Madarang E, Muthiah C, Kassner J, Rampal R, Murthy S, Bradley T, Abaza Y, Garcia J, Gupta V, Pettit K, Odenike O, Patel A. Assessing AML-based risk criteria in patients with accelerated/blast-phase MPN treated with less-intensive therapy. Blood Advances 2025, 9: 2453-2457. PMID: 39969200, PMCID: PMC12144506, DOI: 10.1182/bloodadvances.2024015712.Peer-Reviewed Original ResearchImpact of memory T cells on SARS-CoV-2 vaccine response in hematopoietic stem cell transplant
VanOudenhove J, Liu Y, Nelakanti R, Kim D, Busarello E, Ovalle N, Qi Z, Mamillapalli P, Siddon A, Bai Z, Axtmayer A, Corso C, Kothari S, Foss F, Isufi I, Tebaldi T, Gowda L, Fan R, Seropian S, Halene S. Impact of memory T cells on SARS-CoV-2 vaccine response in hematopoietic stem cell transplant. PLOS ONE 2025, 20: e0320744. PMID: 40294012, PMCID: PMC12036906, DOI: 10.1371/journal.pone.0320744.Peer-Reviewed Original ResearchConceptsHematopoietic stem cell transplantationMemory T cellsStem cell transplantationCell transplantationT cellsSARS-CoV-2Hematopoietic stem cell transplant recipientsAntigen-specific T-cell activationSARS-CoV-2 mRNA vaccinesSARS-CoV-2 vaccine responsesSevere diseaseAnti-spike IgGT cell activationAdaptive immune responsesRobust antibody responsesPost-vaccination responseSARS-CoV-2 infectionMRNA vaccine seriesSingle-cell RNAMyeloablative chemotherapyCellular responsesImmune profileVaccine responseCOVID-19 infectionMRNA vaccinesInvestigation of NPM1 mutation frequency in cutaneous blastic plasmacytoid dendritic cell neoplasms
Hamdan H, Siddon A, Ramia de Cap M, Germans S, Cantu M, Fuda F, Vandergriff T, Aggarwal N, Weinberg O. Investigation of NPM1 mutation frequency in cutaneous blastic plasmacytoid dendritic cell neoplasms. Human Pathology 2025, 158: 105766. PMID: 40216030, DOI: 10.1016/j.humpath.2025.105766.Peer-Reviewed Original ResearchConceptsBlastic plasmacytoid dendritic cell neoplasmBPDCN patientsBPDCN casesCutaneous blastic plasmacytoid dendritic cell neoplasmAcute myeloid leukemiaPlasmacytoid dendritic cell neoplasmDendritic cell neoplasmNPM1 mutationsMyeloid sarcomaCell neoplasmsSarcoma patientsImmunohistochemical stainingAbsence of NPM1 mutationsFrequency of NPM1 mutationsBone marrow of patientsLow white blood cell countCutaneous myeloid sarcomaWhite blood cell countMarrow of patientsTime of diagnosisHigher hemoglobin levelsBlood cell countPercentage of involvementSRSF2 mutationsComplex karyotype
Academic Achievements & Community Involvement
Clinical Care
Overview
Alexa Siddon, MD, is a pathologist who specializes in diagnosing diseases of the blood, such as leukemia and disorders, including bone marrow failure. Her interest in medicine began at a young age, when she accompanied her mother to the workplace—a clinical laboratory. In college, Dr. Siddon completed emergency medical technician (EMT) training and, later, decided to attend medical school.
“I chose pathology because I enjoy putting together the entire story of a patient to make a diagnosis,” says Dr. Siddon, who directs the hemopathology lab at the Veteran Affairs Connecticut Healthcare System. When examining patient samples, Dr. Siddon relies on an arsenal of sophisticated tools to make an accurate diagnosis. “For example, we might look at a bone marrow sample under a microscope, and we would also do genetic sequencing to see if we can discover genetic mutations that might make the patient eligible for a clinical trial.”
“My main focus is patient care,” Dr. Siddon says. “The more information I can give our colleagues, including hematology oncologists, the better care they can provide.”
At Yale School of Medicine, Dr. Siddon is an assistant professor of laboratory medicine.
Clinical Specialties
Fact Sheets
Cytogenic Studies for Leukemia Diagnosis
Learn More on Yale MedicineDiagnosing Leukemia
Learn More on Yale Medicine
News
News
- June 08, 2026
Pathology, Laboratory Medicine Honor Residents, Fellows in Graduation Ceremony
- May 06, 2026
17 Pathology Faculty Members Listed Among Connecticut’s Top Doctors
- March 17, 2026
Yale Pathology Will Have Strong Presence at USCAP 2026
- June 12, 2025
Pathology, Laboratory Medicine Residents, Fellows Feted at Graduation Ceremony
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