Autosomal recessive inheritance of a platelet phenotype that mimics Paris-Trousseau thrombocytopenia. (A) Pedigree of the consanguineous family with the probands in black. (B) MGG stained blood film showing a normal sized platelet (thin arrow) and giant platelet (thick arrow). (C) Platelet aggregation measured by Multiplate in homozygous R324W FLI1 blood (top, II.2) and heterozygous R324W FLI1 (bottom, I.1) in response to arachidonic acid (AA) in blue and collagen in red. (D) Western blotting using monoclonal antibodies against MYH10 (mouse monoclonal, clone A-3) and MPL (rabbit polyclonal), with tubulin (mouse monoclonal, clone SAP.4G5) used as protein loading control, on probands (II.1 and II.2), their parents (I.1 and I.2), and unrelated controls (C1, C2). (E) Photographs of II.1 platelet EM demonstrating α-granule defect characteristic of Paris-Trousseau thrombocytopenia on the left compared with a platelet with normal granule appearance on the right.