Any syndrome in which the cause of the disease is a mutation in the MECOM gene. MECOM-associated syndrome has a variable phenotypic pattern, ranging from isolated radioulnar synostosis with no or mild hematological involvement to severe bone marrow failure without obvious skeletal abnormalities. The clinical picture can also include clinodactyly, cardiac and renal malformations, B-cell deficiency, amegakaryocytic thrombocytopenia, and presenile hearing loss. The disease is Monarch Disease Ontology identifier MONDO_0100458 (MECOM-associated syndrome).