Patients carrying GALE variants showed giant and/or grey platelets in blood films and impaired granules secretion. (A) Family segregation of the variants affecting GALE identified by whole-exome sequencing. Probands are indicated with black arrows. Partially filled symbols in purple or green represent heterozygous status for the indicated GALE variant. (B) Representative peripheral blood films from probands of the 2 pedigrees after May-Grunwald Giemsa staining (×100). Red and black arrows indicate grey and giant platelets, respectively. (C) GPs expression in control and patients, assessed by flow cytometry with fluorescent-labeled antibodies anti-CD42a, CD42b, GPVI, and CD61. The MFI of each antibody, standardized by size (FSC) and relative to the control sample, is represented. (D-E) Platelets from healthy control and family members were stimulated with agonists in the presence of appropriate monoclonal antibodies to assess (D) alpha granules secretion (anti-CD62P), (E) dense granules secretion (anti-CD63) evaluated by flow cytometry. Plots show the percentage of positive platelets. a.u., arbitrary units; ADP, Adenosine diphosphate; CRP; collagen-related peptide; MFI, mean fluorescence intensity; PBS; phosphate-buffered saline; TRAP; thrombin receptor activator peptide.