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When you’re pregnant, it seems that there’s an endless number of tests to be done. Everything from infection to genetic disease usually gets tested for at one time or another. In this blog, we’re going to add one more to the list of diseases that you may want to think about. It’s actually a family of diseases called hemoglobinopathies.
What is Hemoglobinopathy?
When we talk about hemoglobinopathy, we’re referring to a disorder of the oxygen carrying cells of the blood known as red blood cells. The part of the red blood cell that does the work of carrying the oxygen is known as hemoglobin, which is made up of two main parts. The iron-containing heme binds to oxygen, and the protein known as globin, which is attached to the heme, assists with transport and delivery of that oxygen.
Sometimes, due to inherited defects, one (or both) of two things can happen. The blood cells may not make enough globin, or the globin the cells do make may not be normally formed. If these things happen, there can be a couple of issues:
- There can be problems carrying enough oxygen in the blood. This is a type of anemia. Unlike many types of anemia, this can’t be fixed by giving iron. The anemia can be severe and may cause not only fatigue and poor growth, but problems with vital organs such as the heart and spleen.
- The red blood cells can lose their shape and plug the vessels carrying them, leading to many different problems in affected organs. The most common hemoglobinopathy to do this is sickle cell disease.
….and How Common?
Although there are many, many hemoglobinopathies which are very rare, there are some which, while still fairly uncommon, we see a little more frequently. All states now do newborn screening for hemoglobinopathies. An examination of newborn records in California found that 1 in 6,600 births had sickle cell disease, 1 in 9,000 births had alpha-thalassemia, and 1 in 55,000 births had beta-thalassemia. The latter two conditions stem from an inability to make enough globin proteins to form a sufficient amount of hemoglobin. While it’s true that hemoglobinopathies are more prevalent in those of African, Mediterranean and Asian descent, no ethnicity is immune from any of the hemoglobinopathies.
Screening: Why and How
There are very good reasons not to have a hemoglobinopathy. Although it’s not possible to predict how severely a child will be affected, those with sickle cell disease are prone to increased serious infections. They often need antibiotics to prevent an infection turning bad, sometimes in the hospital. They’re prone to other problems such as bone pain, belly pain, and severe anemia due to all the blood pooling in the spleen.
Patients with thalassemia can suffer from anemia severe enough to need regular transfusions. They can have heart failure and damage to other organs from too much iron floating around in the blood.
Although there are treatments to prevent complications from hemoglobinopathies, the only cure is through stem cell transplantation—no easy feat. For all these reasons, it’s recommended that parents be screened for hemoglobinopathies. Today’s parents may not be aware that they have one, because not all states have been screening people for a long time, and mild “carrier” states occasionally go unreported.
Screening involves any one of a number of blood tests. Usually, testing is done to look for an abnormal hemoglobin. Generally, both parents have to have genetic material for a “bad” hemoglobin to make the baby sick (although one parent can have a sickle cell gene and another a thalassemia gene, and the baby can have significant disease).
Screening of the parents can be done before conception. If the mother is already pregnant, it can still be done. If both parents carry a gene for a hemoglobinopathy, there are various ways of testing the fetus. As with lots of inherited diseases, there’s about a 1 in 4 chance that a child of carriers of the disease will be affected. If it turns out that a fetus will have a hemoglobinopathy, parents can talk with their obstetrician—maybe also with a hematologist and a genetic counselor—about whether to continue the pregnancy, taking into account the amount of disease the hemoglobinopathy is likely to cause and the wishes and beliefs of the parents. These conversations also help families plan what to expect both with the current baby-to-be and any born in the future.
Hemoglobinopathy is not an easy diagnosis to give. However, it’s one that’s better known sooner rather than later. Unlike many other problems thatit can’t be prevented as can other problems that crop up in the prenatal period. However, more knowledge can lead to better decisions for everyone concerned—even if it means yet another test.