Carriers of GALE p.Lys78ValfsX32, p.Thr150Met, p.Val128Met, and p.Leu223Pro variant displayed VWF delocalization within the MK membrane. MKs were differentiated from peripheral blood progenitor cells (probands A.II.4 and B.II.2) through a 14-days culture, in parallel with healthy controls. (A) Representative image of alpha-granules in mature-polyploid MKs and MK forming proplatelets in control, A.II.4, and B.II.2. Cells were stained with an anti-β3 integrin antibody (green). Alpha-granules were stained with anti-VWF (red). Hoechst (blue) was used for counterstaining nuclei. Arrows indicate the presence of VWF in the control MK membrane, whereas both A.II.4 and B.II.2 had a severely reduced expression of VWF in the membrane. (B) Fluorescence intensity distribution of VWF, relativized with β3 integrin (ratio VWF-β3 integrin), in the MK membrane from healthy controls, A.II.4, and B.II.2. Scale bars, 20 μm. ∗∗∗P < .001; ∗P < .05; 2-tailed Student t test.