How does thalassemia major first show itself?
During pregnancy the inherited thalassemia major does not affect the fetus. This is because the fetus has a special sort of hemoglobin, called “fetal hemoglobin” (HbF for short). Children and adults have a different hemoglobin called “adult hemoglobin” (HbA for shot). When a baby is born, most of its hemoglobin is still the fetal kind, but during the first 6 months of life it is gradually replaced with adult hemoglobin. The problem with thalassemia, is that the child cannot make adult hemoglobin. Therefore children with thalassemia major are well at birth, but usually become ill before they are 18 months old. They usually become quite anemic (their Hb level is usually less than 8 g/dl). So they become pale, do not grow as well as they should, and often have a big spleen. The number of months that can pass before a thalassemic child becomes ill, can differ quite a lot from case to case. This is because thalassemia can be caused by several different defects in the hemoglobin genes. Some
