Relevance of early diagnosis in polycythemia vera and essential thrombocythemia: A single center's experience

OBJECTIVES

This work aims to describe the proportion of patients with polycythemia vera (PV) or essential thrombocythemia (ET) and thrombosis prior to the diagnosis who had erythrocytosis or thrombocytosis prior to the thrombosis.

PATIENTS AND METHODS

This is a retrospective review of 63 patients with PV and 130 with ET.

RESULTS

In regard to PV, we found prior erythrocytosis in 7 (11.1%) of the 17 cases (27%) with thrombosis prior to diagnosis. In ET, we found prior thrombocytosis in 10 (7.7%) of the 25 cases (19.2%) with thrombosis prior to diagnosis. The median time between the laboratory finding and thrombosis was 8.2 months and 11.8 months for PV and TE, respectively. In both entities, patients with thrombosis prior to diagnosis had significantly lower survival.

CONCLUSION

A significant proportion of patients with thrombosis prior to the diagnosis of PV and ET present with erythrocytosis or thrombocytosis prior to the episode of thrombosis. This could allow for anticipating diagnosis and treatment.

Alx3-deficient mice exhibit folic acid-resistant craniofacial midline and neural tube closure defects

Neural tube closure defects are among the most frequent congenital malformations in humans. Supplemental maternal intake of folic acid before and during pregnancy reduces their incidence significantly, but the mechanism underlying this preventive effect is unknown. As a number of genes that cause neural tube closure defects encode transcriptional regulators in mice, one possibility is that folic acid could induce the expression of transcription factors to compensate for the primary genetic defect. We report that folic acid is required in mouse embryos for the specific expression of the homeodomain gene Alx3 in the head mesenchyme, an important tissue for cranial neural tube closure. Alx3-deficient mice exhibit increased failure of cranial neural tube closure and increased cell death in the craniofacial region, two effects that are also observed in wild type embryos developing in the absence of folic acid. Folic acid cannot prevent these defects in Alx3-deficient embryos, indicating that one mechanism of folic acid action is through induced expression of Alx3. Thus, Alx3 emerges as a candidate gene for human neural tube defects and reveals the existence of induced transcription factor gene expression as a previously unknown mechanism by which folic acid prevents neural tube closure defects.