Schematic illustration of MK lineage commitment, growth and differentiation, and maturation and platelet release. Causative genes involved in congenital thrombocytopenias are listed as well as in supplemental Table 1. The upper illustration depicts the “genes” in individual developmental stages related to thrombocytopenia in humans. The lower illustration shows the membrane glycoproteins and cytoskeletal structure components within platelets. For example, the physical linkage of the GPIb–filamin A–actin cytoskeleton is responsible for both platelet biogenesis and morphology. Macrothrombocytopenia induced by activating mutations of GPIIb/IIIa (integrin αIIbβ3) is probably caused by myosin IIA–dependent cascade.