Since these diseases are phenotypically identical, we hypothesized an interplay between ETV6 and ANKRD26 and found that ANKRD26 interacts with ETV6 through GPS2, preventing the transcription factor from entering the nucleus to exert its functions and suggesting a common mechanism in the pathogenesis of these three tumor-predisposing inherited thrombocytopenias. The gene discussed is GPS2; the disease is Thrombocytopenia.