Platelet and MK analysis. (A) Cytological investigation of blood platelets. The black arrows point to platelets in the blood smears. Note the much larger platelet size for patients (II-1 and II-2) compared with control (C). (B) Ultrastructural aspect of blood platelets. Large platelets were detected in blood of II-1 and II-2 patients, and platelets of normal size were detected in 1 control and in a I-1 family member with the heterozygous PRKACG mutation. (C) The size of 100 platelets for control, I-1, II-1, and II-2 individuals was measured. The results represent mean ± SEM. ***P < .0001, unpaired Student t test (2-tailed). (D) Cytological investigations of the bone marrow of II-1 and II-2 patients and control. (E) MK differentiation was induced from control or patient peripheral blood CD34+ cells and analyzed at day 10 of culture. Gates represent mature (CD41+CD42+) or immature (CD41+CD42−) MKs (left). The ploidy level (N) was analyzed in the gate of CD41+CD42+ MKs and was based on the percentage of cells in 8N, 16N, and 32N gates.