ANKRD26-related thrombocytopenia is characterized by lifelong mild-to-moderate thrombocytopenia with a normal platelet size and no syndromic associations. Most individuals have normal hemostasis or a mild bleeding phenotype and do not develop severe spontaneous bleeding. Some individuals may have concomitant erythrocytosis and leukocytosis. The risk for myeloid malignancies (including myelodysplastic syndrome, acute myelogenous leukemia, and chronic myelogenous leukemia) is increased in individuals with ANKRD26 pathogenic variants.