 To this end, eltrombopag will be given for 3-6 weeks to patients with different forms of inherited thrombocytopenia. Eltrombopag will be administered at the dosage of 50 mgday for 3 weeks. After 3 weeks of treatment, the patients who will obtain a platelet count higher than 100 x10e9L will stop therapy. The patients who will achieve a platelet count lower than 100 x10e9L will be treated with eltrombopag at a higher dosage 75 mgday for 3 additional weeks. This treatment schedule is called Phase 1 of the study. 