Anemia caused by the reduction of hemoglobin in relation to the red cell volume. As a result, the red cells have an area of central pallor which is increased in size. The leading cause is iron deficiency. The disease is Monarch Disease Ontology term MONDO_0001357 (hypochromic anemia). Also known as: anaemia hypochromic, anemia hypochromic, hypochromic anaemia (disease), hypochromic anemia (disease).