There is only one copy for each chain on each chromosome. The Alpha-chain gene is located on chromosome 16 . There are two Alpha-chain genes on each chromosome. Both Alpha and Beta-thalassemia are characterized by microcytic anemia. In thalassemia, the red blood count is relatively higher than expected for the level of hemoglobin.
Hydrops fetalis results from four Alpha-chain gene deletions .
Hemoglobin Barts is used as a newborn screening test for Alpha-thalassemia. He had no history of blood loss, drug intake or previously similar episodes. There was no positive family history of anemia, blood transfusion, cholecystectomy or neonatal jaundice. His physical examination revealed a very pale child with mild jaundiced and marked irritability. His spleen was 3 cm below the left costal margin and the liver was 2 cm below the right costal margin.