ACTN1-related Macrothrombocytopenia: A Novel Entity in the Progressing Field of Pediatric Thrombocytopenia

The most common cause of thrombocytopenia in children is immune thrombocytopenia. Nevertheless, some atypical
cases should evoke the hypothesis of genetic thrombocytopenia.
Indeed, in the past years, 30 new genes had been described in
the field of inherited thrombocytopenia. We report a series of 11
cases of a newly diagnosed entity: ACTN1-related macrothrombocytopenia. Mutations in the gene ACTN1 cause mild
macrothrombocytopenia characterized by elevated mean platelet
volume and elevated immature platelet fraction, and low bleeding
tendency. Its transmission is autosomal dominant. Molecular
diagnosis is made by sequencing the ACTN1 gene. Its potential role
in hematological malignancy predisposition remains unclear and
should be clarified. Conclusion: We identified 11 patients with
ACTN1-related macrothrombocytopenia diagnosed through
pediatric probands. The aim was to underline the specificities of
this entity, especially in children, and bring it to the knowledge of
pediatricians.