Alpha thalassemia

Newborn screening for Alpha thalassemia requires collecting a small amount of blood from your baby’s heel. To learn more about this process, visit the Blood Spot Screening page.

Screening measures certain types of hemoglobins in your baby’s blood. Babies with a hemoglobin known as “Bart’s hemoglobin” may have one of the types of Alpha thalassemia. Typically, the more Bart’s hemoglobin present, the more severe the type of Alpha thalassemia. Bart’s hemoglobin gets its name because it was originally discovered at St. Bartholomew’s Hospital in London.

If your baby’s blood spot screening result for Alpha thalassemia needs follow-up, your baby’s health care provider will contact you. Together, you will discuss next steps and follow-up plans.

An out-of-range screening result usually means that your baby has one of the Alpha thalassemia types and your baby may need more follow-up testing. To learn more about screening results, visit the Blood Spot Screening Results page.

Your baby may need the following tests after an out-of-range screening result:

• Blood tests
• Genetic testing using a blood sample

You should complete any recommended follow-up testing as soon as possible. Babies with severe types of Alpha thalassemia can have serious health problems if they are not diagnosed and treated.

False-positive newborn screening results for this condition are rare. However, screening samples that are collected after a baby receives red blood cells from someone else (a red cell transfusion) will be inaccurate.

Newborn screening helps babies lead healthier lives. If your baby has an out-of-range result, follow up with your health care provider quickly. It is important to follow their instructions. Your baby may need to get treatment right away, even if they are not showing signs or symptoms. In some cases, your baby’s health care provider may decide it is best to watch (monitor) your baby to decide next steps. Careful monitoring and early treatment will help your baby stay as healthy as possible.

Signs and symptoms of Alpha thalassemia depend on the type of Alpha thalassemia a baby has. In some cases, signs of the condition appear right at birth. In these cases, it is important to see a doctor and start treatment quickly. Other children may only have minor signs and symptoms.

Signs of the condition may include the following:

Silent Carrier

• Usually has no signs or symptoms

Alpha thalassemia Minor

• Typically, no signs or symptoms at birth
• May develop mild anemia (low levels of red blood cells)

HbH Disease

• Typically, no signs or symptoms at birth
• Usually develop moderate to severe anemia (low levels of red blood cells) in childhood, which leads to:
  • Pale or yellow skin or eyes (jaundice)
  • Feeling tired or weak
  • Large liver and spleen (hepatosplenomegaly)
  • Slow growth or delayed puberty
  • Bone problems
  • Darker urine

Alpha Thalassemia Major

• These babies usually do not live very long after birth, unless the disorder is identified in utero and in utero transfusions are provided.

Alpha thalassemia is caused by changes in the HBA1 and/or HBA2 genes. These genes give the body instructions for making alpha-globin, a protein found in hemoglobin.

Your baby has two copies (alleles) of each gene, for a total of four alpha globin alleles (HBA1, HBA1, HBA2, HBA2). The number of alpha globin alleles that are missing or changed determines what type of Alpha thalassemia your baby has. The missing or changed allele can be either HBA1 or HBA2.

• An Alpha thalassemia silent carrier has three normal alpha globin alleles and one missing allele. Their three normal alleles make enough working hemoglobin to bring oxygen to their body. This is why they usually have no symptoms.
• A baby with Alpha thalassemia minor has two normal alpha globin alleles and two missing alleles. Their two normal alleles make enough working hemoglobin most of the time.
• There are two forms of HbH disease. A baby with deletional HbH disease has one normal alpha globin gene and three missing alleles. A baby with non-deletional HbH disease has one normal alpha globin gene, one changed gene, and two missing alleles. In HbH disease, one normal gene makes a small amount of normal hemoglobin so that people can lead healthy lives with monitoring and/or treatment.
• A baby with Alpha thalassemia major does not have any normal alpha globin alleles. Their bodies cannot make any normal hemoglobin. This condition is so serious that damage to their body begins before birth and survival is rare.

Alpha thalassemia is a genetic condition. Babies inherit it from their biological (birth) parents. To learn more about genetic conditions, visit MedlinePlus Genetics.

• Alpha thalassemia is inherited in a complex way, but usually in an autosomal recessive manner.
• For each of the two alpha-globin genes (HBA1 and HBA2) one allele is inherited from the mother, and the other allele is inherited from the father.
• Babies inherit the silent carrier type of Alpha thalassemia when only one parent passes down one missing HBA1 or HBA2 allele.
• Babies inherit Alpha thalassemia minor when parents pass down two missing HBA1 or HBA2 alleles.
• Babies inherit HbH disease when parents pass down three missing HBA1 or HBA2 alleles.
  • If one parent has Alpha thalassemia minor and the other parent is a silent carrier, there is a 1 in 4 chance with each pregnancy that the baby will have HbH disease.
• Babies inherit Alpha thalassemia major when parents pass down four missing HBA1 or HBA2 alleles.
  • If both parents have Alpha thalassemia minor, there is a 1 in 4 chance with each pregnancy that the baby will have Alpha thalassemia major.
• Genetic counselors and medical geneticists can help families learn about this condition and the chance of having children with it. Visit the National Society of Genetic Counselors to find a genetic counselor and the American College of Medical Genetics and Genomics to find a medical geneticist.