Pedigree of affected family, light microscopy of red blood cells, and electron microscopy of platelets.

(A) Patients with the X-linked thrombocytopenia are represented by filled symbols, female carriers by dotted circles. (B) Light microscopy (magnification × 1000) of dysmorphic red blood cells in peripheral blood smear of affected patient after May-Grünwald-Giemsa staining, showing anisocytes, poikilocytes, megalocytes, and acanthocytes. (C) Electron microscopy (magnification × 12 600) of platelets. Left panel: platelets of a normal individual. Discoid platelets and more round forms with normal organelles and granules. Right panel: platelets of affected patient (representative of the 6 patients studied). Enlarged round platelet showing a cytoplasmic cluster composed of smooth endoplasmic reticulum and abnormal membrane complexes. Note paucity of alpha granules.