Radioulnar Synostosis with Amegakaryocytic Thrombocytopenia 1, also known as thrombocytopenia, congenital, with radioulnar synostosis, is related to radioulnar synostosis, nonsyndromic and radioulnar synostosis with amegakaryocytic thrombocytopenia 2, and has symptoms including petechiae of skin An important gene associated with Radioulnar Synostosis with Amegakaryocytic Thrombocytopenia 1 is HOXA11 (Homeobox A11). Affiliated tissues include bone marrow and bone, and related phenotypes are sensorineural hearing impairment and clinodactyly of the 5th finger