Aggregates of non-muscular myosin IIA in erythrocytes associate with GATA1- and GFI1B-related thrombocytopenia

Carlo Zaninetti, Jose' Rivera, Leonard Vater, Sandra Ohlenforst, Eva Leinøe, Doris Böckelmann, Kathleen Freson, Thomas Thiele, Houssain Makhloufi, Matthias Rath, Wolfgang Eberl, Martina Wolff, Carmen Freyer, Jan Wesche, Barbara Zieger, Ute Felbor, Florian H Heidel, Andreas Greinacher*

*Corresponding author for this work


BACKGROUND: The transcription factor GATA1 is an essential regulator of erythroid cell gene expression and maturation and is also relevant for platelet biogenesis. GATA1-related thrombocytopenia (GATA1-RT) is a rare X-linked inherited platelet disorder (IPD) characterized by macrothrombocytopenia and dyserythropoiesis. Enlarged platelet size, reduced platelet granularity, and noticeable red blood cell anisopoikilocytosis are characteristic but unspecific morphological findings in GATA1-RT.

OBJECTIVES: To expand the investigation of platelet phenotype of patients with GATA1-RT by light- and immunofluorescence microscopy on a blood smear.

METHODS: We assessed blood smears by light- and immunofluorescence microscopy after May-Grünwald Giemsa staining using a set of 13 primary antibodies against markers belonging to different platelet structures. Antibody binding was visualized by fluorescently labeled secondary antibodies.

RESULTS: We investigated 12 individuals with genetically confirmed GATA1-RT from 8 unrelated families. While confirming the already known characteristic of platelet morphology (platelet macrocytosis and reduced expression of markers for α-granules), we also found aggregates of nonmuscular myosin heavy chain II A (NMMIIA) in the erythrocytes in all individuals (1-3 aggregates/cell, 1-3 μm diameter). By systematically reanalyzing blood smears from a cohort of patients with 19 different forms of IPD, we found similar NMMIIA aggregates in the red blood cells only in subjects with GFI1B-related thrombocytopenia (GFI1B-RT), the other major IPD featured by dyserythropoiesis.

CONCLUSION: Aggregates of NMMIIA in the erythrocytes associate with GATA1-RT and GFI1B-RT and can facilitate their diagnosis on blood smears. This previously unreported finding might represent a novel marker of dyserythropoiesis assessable in peripheral blood.

Original languageEnglish
JournalJournal of thrombosis and haemostasis : JTH
Issue number4
Pages (from-to)1179-1186
Number of pages8
Publication statusPublished - Apr 2024


  • Anemia
  • Blood Platelets/metabolism
  • Erythrocytes
  • GATA1 Transcription Factor/genetics
  • Humans
  • Nonmuscle Myosin Type IIA
  • Proto-Oncogene Proteins/genetics
  • Repressor Proteins/genetics
  • Thrombocytopenia
  • blood platelets
  • inherited thrombocytopenia
  • erythrocytes
  • blood morphology
  • immunofluorescence


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