Beta globin gene mutations can lead to decreased production as well as inactivation of the gene. Not all of these mutations have been defined with DNA analysis, though many of them have and many are constantly being defined. There are over 150 known mutations in the beta globin gene, producing beta thalassemia trait in the heterzygotic individual, and causing a variable degree of anemia in the homozygote. In addition, there are mutations such as that leading to hemoglobin E, which do not produce disease even in the homozygous state. However, hemoglobin E combined with other variant beta globins can produce mild to severe anemia.
Many variant hemoglobins exist worldwide.
Hemoglobins E and S are significant because they can be co-inherited with thalassemia trait to produce a disease that requires treatment. Hgb E-Beta thalassemia has a wide range of clinical manifestations, from mild anemia to significant anemia requiring chronic tranfusions. The clinical manifestations of this disease resemble Hgb SS disease. Newborn Screening and Hemoglobin E A newborn screening result of Hgb EF or Hgb FE will be presumed to be Hgb E-beta thalassemia, and requires repeat electrophoresis and family studies to confirm or deny diagnosis. Hemoglobin E is the most common abnormal hemoglobin identified in the state of California on newborn screening.