Essential thrombocythemia in two sisters originating from different stem cell levels

Area of Science:

• Hematology
• Genetics
• Oncology

Background:

• Essential thrombocythemia (ET) is a rare myeloproliferative neoplasm.
• Familial occurrences of ET are uncommon, prompting further investigation into underlying genetic factors.
• Understanding the clonal origin of ET is crucial for disease classification and management.

Purpose of the Study:

• To investigate the occurrence and clonal basis of essential thrombocythemia in a familial setting.
• To analyze the evolution of clinical phenotype in a patient with ET.
• To determine the stem cell origin of clonal hematopoiesis in ET.

Main Methods:

• X-chromosomal inactivation analysis using phosphoglycerate-kinase (PGK) gene polymorphism to assess clonality.
• Cell separation techniques to isolate different hematopoietic lineages.
• Longitudinal clinical follow-up to monitor disease progression.

Main Results:

• Essential thrombocythemia was identified in two sisters, a rare familial presentation.
• One patient's condition evolved from ET to polycythemia vera (PV) over four years.
• Clonal hematopoiesis was confirmed in both patients via PGK gene analysis.
• Monoclonality suggested a common progenitor for multiple cell types in one sister, while the other showed monoclonality primarily in granulocytes.

Conclusions:

• Familial ET can occur and may involve distinct stem cell origins.
• The observed evolution from ET to PV highlights the dynamic nature of myeloproliferative neoplasms.
• These findings suggest that ET may arise from heterogeneous stem cell levels, impacting disease presentation and progression.