Macrocytic anemia: Macrocytic anemia is a blood disorder where the red blood cells are larger than normal but have low levels of haemoglobin which is needed to carry oxygen throughout the body. The condition usually results from a deficiency of vitamin B12 or folate, digestive problems, malabsorption and certain medications which affect folic acid levels. Various rare inherited disorders may also result in macrocytic anemia e.g. Lesch-Nyhan syndrome. Severity and range of symptom may vary depending on the underlying condition.