Effect of DIAPH1 R1213* variant on platelet morphology. Illustration of the typical platelet morphology for cases 10, 16, 17, and 21. (A) Arrows highlight platelets of different size (case 21). Original magnification, ×100; May-Grünwald-Giemsa stain. (B) Transmission electron microscopy (TEM) revealed an abnormal large granule (LG) (case 21). (C) TEM image of control platelets shows they are discoid and of regular size and have homogeneously distributed granules. All examined platelets of the patients show a heterogeneous size, shape, and distribution of α granules. (D) TEM image of a very thin elongated platelet and other platelets with a more round shape with few granules (case 10). (E) TEM image illustrates a very round platelet with many granules (case 17). (F) TEM of platelets from case 16 revealed an abnormal presence of vacuoles (V) and a membrane complex (MC). Bars represent 1 μm. The TEM images were acquired using either an EM900 (Carl Zeiss) or a JEM-1010 (JEOL) transmission electron microscope.