What is the chance a child will have sickle cell if one parent has it and the other parent does not and is homozygous?

What is hemoglobin?
Where does your hemoglobin come from?
What is hemoglobinopathy?
What is sickle cell trait?
How will I know if I have sickle cell trait?
Where can I be tested for sickle cell trait?
What is sickle cell disease?
What are "sickle cell conditions"?
How do you get sickle cell anemia or trait?
How common is sickle cell anemia?
How is sickle cell anemia detected?
How is the testing done?
What are the chances of having a baby with sickle cell trait?
What are the chances of having a baby with sickle cell disease?
What medical problems are caused by sickle cell disease?
What should future parents know?
How can I be tested?
What services are available in Missouri for persons with sickle cell conditions?
Where can I get more information about services available in Missouri?
What does DHSS offer for adult sickle cell patients 21 years of age and older?

What is hemoglobin?
Hemoglobin (Hb) is the special protein within the red blood cells that carries oxygen from the lungs to the rest of the body. Hemoglobin is what makes your blood look red in color.

Where does your hemoglobin come from?
Your hemoglobin type is inherited through family genes. The color of your hair, the color of your eyes, and your hemoglobin type are all examples of things that are determined by genes. You receive one gene for hemoglobin type from your mother and one from your father. Hemoglobin A or normal adult hemoglobin is the most common type. There are over 500 different types or variations of hemoglobin.

What is hemoglobinopathy?
Hemoglobinopathy is a term used to describe disorders caused by the presence of abnormal hemoglobin production in the blood.

What is sickle cell trait?
Sickle cell trait occurs when a person inherits a normal hemoglobin gene (Hb A) from one parent, and a sickle hemoglobin gene (Hb S) from the other parent. This results in hemoglobin AS or sickle cell trait. A person with sickle cell trait may also be called a sickle cell carrier. Sickle cell trait is not a disease and usually does not affect one's health, but individuals with sickle cell trait can pass the sickle hemoglobin gene to their children.

How will I know if I have sickle cell trait?
A simple blood test called a hemoglobin electrophoresis will detect sickle cell trait. This test will tell if you are a carrier of the sickle cell trait or if you have the disease.

Where can I be tested for sickle cell trait?
Your physician can give you the test or the test may be obtained at some hospitals, sickle cell centers, and health department clinics.

What is sickle cell disease?

Sickle cell anemia (Hb SS) is the most common type of sickle cell disease. There are other hemoglobin types such as hemoglobin C or hemoglobin E, that in combination with the gene for sickle hemoglobin can result in different forms of sickle cell disease (Hb SC, Hb SE, Hb S/beta thalassemia).

What are "sickle cell conditions"?
They are sickle cell trait and the various types of sickle cell disease.

How do you get sickle cell anemia or trait?
You inherit the abnormal hemoglobin from your parents. You cannot catch it from someone else or pass it to another person like a cold or other infections. You are born with sickle cell hemoglobin and it is present for life. If you inherit only one sickle gene, you have sickle cell trait and will not develop the disease. If you inherit two sickle cell genes, you have sickle cell anemia.

How common is sickle cell anemia?
Sickle cell anemia affects millions of people throughout the world. It is particularly common among people whose ancestors come from Africa; Spanish speaking regions (South America, Cuba, Central America); Saudi Arabia; India; and Mediterranean countries, such as Turkey, Greece, and Italy. In the United States, most people who have sickle cell disease are African American. In Missouri, the disease occurs in approximately 1 in every 400 African-American births, and approximately 1 in 12 African Americans carry the sickle cell trait.

How is sickle cell anemia detected?
Most states now perform a blood test for sickle cell disease on all newborn infants. Early diagnosis of sickle cell anemia is critical so that children who have the disease can receive proper treatment. Since May 1989, all babies born in Missouri are tested for sickle cell conditions through the Missouri Newborn Screening Program (MNSP). This test is performed at the same time and from the same blood samples as other routine newborn screening tests. If the test shows the presence of sickle hemoglobin, a second blood test is performed to confirm the diagnosis. These tests also tell whether the child carries the sickle cell trait.

How is the testing done?
A small blood sample is taken from the infant's heel, usually before the baby leaves the hospital. The blood sample will show whether the baby has sickle cell trait, sickle cell disease or any other abnormal hemoglobin.

What are the chances of having a baby with sickle cell trait?

• two normal hemoglobin genes, or
• one normal hemoglobin gene and one sickle cell gene.

With EACH pregnancy there is a:

• 50% chance that the baby will have normal red blood cells (AA).
• 50% chance that the baby will have sickle cell trait (AS).

What are the chances of having a baby with sickle cell disease?

• two normal hemoglobin genes, or
• one normal hemoglobin gene and one sickle cell gene, or
• two sickle cell genes

With EACH pregnancy there is a:

• 25% chance that the baby's red blood cells will be normal (AA).
• 50% chance that the baby will have sickle cell trait (AS).
• 25% chance that the baby will have sickle cell disease (SS).

What medical problems are caused by sickle cell disease?
Sickle shaped red blood cells tend to get stuck in narrow blood vessels blocking the flow of blood. This can cause damage to organs including the spleen, liver and kidneys. Other complications include pain episodes, lung problems and stroke.

What should future parents know?
People who are planning to become parents should know whether they are carriers of the sickle cell gene. If they are, they may want to seek genetic counseling to find out what the chances are that their child will have sickle cell trait or sickle cell anemia.

How can I be tested?
Your doctor can do a simple blood test called a hemoglobin electrophoresis. This test will tell if you are a carrier of the sickle cell trait or if you have the disease.

What services are available in Missouri for persons with sickle cell conditions?

• The Missouri Newborn Screening Program (MNSP) tests newborns for sickle cell and other hemoglobinopathies.
• Family members of infants identified with sickle cell conditions can be screened at county and city health departments, family planning clinics and hospitals.
• Educational genetic counseling is available through the Missouri Sickle Cell Anemia Program (MSCAP) for individuals identified with sickle cell trait or other carrier conditions.
• Educational programs about sickle cell trait and sickle cell disease are available for schools, community groups and other interested groups.
• Hemoglobinopathy (Sickle Cell) Resource Centers are established throughout the State to provide comprehensive services for individuals and families with sickle cell disease. Each resource center is located in a hospital that provides inpatient, outpatient and emergency care.

Where can I get more information about services available in Missouri?
For more information, contact us.

What does DHSS offer for adult sickle cell patients 21 years of age and older?
The Sickle Cell fact sheet provides information for patients 21 years of age and older.

Sickle cell anemia is a genetic disorder where the body produces an abnormal hemoglobin called hemoglobin S. Hemoglobin is the protein in red blood cells that carries oxygen. Red blood cells are normally flexible and round, but when the hemoglobin is defective, blood cells take on a “sickle” or crescent shape. This causes the red blood cells to get stuck inside blood vessels and block blood flow and oxygen transport to some parts of the body, thereby causing sickle cell anemia.

Mutations leading to sickle cell anemia

Hemoglobin is made up of four different protein subunits, which includes two subunits called alpha-globin and two called beta-globin. Sickle cell anemia is caused by mutations in a gene called HBB, which is the gene that provides instructions for the production of beta-globin.

There are multiple mutations that can occur in the HBB gene. One of these leads to the production of hemoglobin S.

Inheritance of sickle cell anemia

Sickle cell anemia is an autosomal recessive disease, meaning that it only occurs if both the maternal and paternal copies of the HBB gene are defective.

In other words, if an individual receives just one copy of the defective HBB gene, either from their mother or their father, they do not have sickle cell anemia but have what is called “sickle cell trait”. People with sickle cell trait usually do not have any symptoms or problems but they can pass the mutated gene onto their children.

There are three inheritance scenarios that can lead to a child having sickle cell anemia:

If both parents have sickle cell trait, then there is a 25 percent risk of the child having sickle cell anemia and a 50 percent risk of them having sickle cell trait. There is also a 25 percent chance that the child will not inherit either copy of the mutated gene.

If one parent has sickle cell anemia and the other has sickle cell trait, there is a 50 percent risk that their children will have sickle cell anemia and 50 percent risk they will have sickle cell trait.

If both parents have sickle cell anemia, then their children will also definitely have the disease.

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Sickle Cell Anemia News is strictly a news and information website about the disease. It does not provide medical advice, diagnosis or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.