Thalassemia Associated With an Abnormal Hemoglobin
Abnormal hemoglobin have an altered structure, and sometimes an altered behavior. Occasionally a person inherits b-thalassemia from one parent, and an abnormal hemoglobin from the other parent. Sometimes this causes problems, and sometimes not.
The important abnormal hemoglobin are:
Hemoglobin S (Hb S)
Hemoglobin C (Hb C)
Hemoglobin E (Hb E)
Hemoglobin D (Hb D)
They are carried in the same way as thalassemia, by healthy carriers who have one gene for normal hemoglobin, and one for the abnormal hemoglobin. Carriers of Hb S, for instance are said to have sickle cell trait, and carriers of HB E are said to have Hb E trait. Carriers of abnormal hemoglobin can be detected by blood tests. Like thalassemia carriers can.
People who inherit Hb S from both parents have sickle-cell disease. But people with inherit Hb C or Hb D or Hb E from both parents are perfectly well.
People who inherit b-thalassemia from one parents and Hb S or Hb E from the other may have a severe anemia.
But people who inherit b-thalassemia from one parent and Hb C or Hb D from the other, are perfectly healthy -- just like healthy carriers of b-thalassemia trait.
Worldwide, HB S is the commonest abnormal hemoglobin. So the commonest combination is HB S/b-thalassemia.
It is rather more like sickle-cell disease than like thalassemia, so we recommend people with HB S/b-thalassemia to read a book written for people with sickle-cell disease.1
1For instance, A Handbook on Sickle Cell Disease: A Guide for Families. Produced by the Sickle Cell Society, c/o Brent Community Health Council, 16 High Street, Harlesden, London NW10 4lX.
Price £1, including postage.
Hemoglobin E (HBE) is very common indeed in parts of India and South-East Asia, and also in part of South Turkey and Eastern Saudi Arabia. So HB E/b-thalassemia is another “combined” form of thalassemia that is common among people from these areas
It is usually but not always milder than b-thalassemia major. In fact, It is usually like thalassemia intermedia. A few people with HB E/b-thalassemia need regular blood transfusions, some need transfusion occasionally, some need to have their spleen removed, and a few are very well with no treatment at all.
So if you have HB E/b-thalassemia, read Section 4 on Thalassemia Intermedia. But there is one thing you should remember as you read it. With HB/b-thalassemia, your blood carries oxygen rather better than in thalassemia intermedia, So you can be stay well at a rather lower hemoglobin level. If your average hemoglobin level is above 7g/dl, you will probably lead a reasonably normal life without regular transfusions. If it is above 8g/dl, you should expect to be very well indeed. However, if it is less than 6.5g/dl, you will probably need blood transfusions, or you may need to have your spleen removed, if it is very big.
The fact is, we do not know as much about HB E/b-thalassemia as about other forms of thalassemia, but we are learning. And we hope we will be able to write more about it in the future.