First Report of MPL c.23T>G (p.M8R) Variant in Congenital Amegakaryocytic Thrombocytopenia: A Case Report.

Congenital amegakaryocytic thrombocytopenia is a rare inherited bone marrow failure syndrome primarily caused by MPL gene mutations. It presents with severe neonatal thrombocytopenia and typically progresses to pancytopenia. We report the first disease-associated case of the MPL variant c.23T>G, identified through whole-exome sequencing in an infant diagnosed with congenital amegakaryocytic thrombocytopenia. Based on ACMG criteria, we propose classification of the MPL c.23T>G (p.M8R) variant as likely pathogenic. This case highlights the importance of early genetic testing in infants with unexplained thrombocytopenia and emphasizes the need to distinguish congenital amegakaryocytic thrombocytopenia from other inherited bone marrow failure syndromes. Trial Registration: The authors have confirmed clinical trial registration is not needed for this submission.