Hemoglobin C disease is a blood disorder that can cause fatigue, weakness, and anemia. It occurs when a person inherits two copies of hemoglobin C genes from their parents.

Hemoglobin is an iron-rich protein that transports oxygen throughout the body. In people with the disease, a specific change in the hemoglobin gene produces an abnormal protein called hemoglobin C.

Having hemoglobin C in the blood can change the shape of blood cells. As a result, some people with the disease develop mild hemolytic anemia.

The condition is usually not serious. It is more common in people of African descent and affects about 1 in 40 African American people.

Below, we explore hemoglobin C disease in more detail, including its symptoms and treatments.

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Hemoglobin C disease is an inherited condition, which means that it passes down in families. It occurs when a genetic mutation affects hemoglobin protein, causing it to produce hemoglobin C instead of hemoglobin A.

In a person without the condition, red blood cells are soft and disk-shaped. They can easily squeeze through blood vessels to transport oxygen throughout the body.

In someone with hemoglobin C disease, the red blood cells are not as flexible and clump together easily. This causes them to break more quickly than usual. This breaking can contribute to hemolytic anemia, a condition in which red blood cells are destroyed faster than the body produces them.

Most people with this type of anemia do not have serious symptoms. However, severe hemolytic anemia can cause fever, chills, pain in the abdomen and back, and shock. And without treatment, it can lead to complications.

The hemoglobin C trait passes from parents to their children. Everyone inherits two hemoglobin genes from their parents. If a baby has a hemoglobin A gene from one parent and a hemoglobin C gene from the other, they develop hemoglobin C trait.

Hemoglobin C is a recessive gene. This means that if both parents have hemoglobin C trait, there is a 25% chance that their child will inherit two hemoglobin C genes. That means they will develop a hemoglobin disorder, such as hemoglobin C disease.

Having hemoglobin C trait is very common, and it is not an illness.

The trait is more prevalent in people of African descent, and it is present in 2–3% of African American people. It is also common in the Mediterranean region, South Europe, South America, South Asia, and the Middle East.

Most people with hemoglobin C disease have no symptoms.

If someone with the condition develops hemolytic anemia, they may experience:

  • weakness
  • paleness of the skin
  • lightheadedness
  • dark-colored urine
  • fever
  • fatigue

Hemolytic anemia symptoms can be similar to those of other blood disorders and other health issues. A person should consult a healthcare professional if they experience:

In newborns, doctors can screen for genetic abnormalities, such as hemoglobin C trait or disease. Because hemoglobin C trait is not an illness, and so causes no symptoms, many people do not know that they have it.

Diagnosing hemoglobin C disease often begins with a review of a person’s medical history and any symptoms. A person’s family medical history may reveal that a parent has the trait.

During a physical examination, the doctor assesses any signs of the condition. They may gently press on different areas of a person’s abdomen to check for tenderness, such as the upper right quadrant behind the ribs, which can indicate an enlarged spleen.

If a doctor suspects hemoglobin C disease, they can perform blood tests to check the amount of hemoglobin in the blood and the presence of any abnormal hemoglobin.

Some of the tests that a doctor may perform include:

Complete blood count: This measures the number of platelets, white blood cells, red blood cells, and hemoglobin in the blood. Abnormally low red blood cell levels can indicate anemia.

Peripheral smear or blood smear: In this test, a doctor looks at a smear of blood under a microscope. They assess the size, shape, and number of platelets, red blood cells, and white blood cells. They also look at how much hemoglobin the red blood cells contain.

Hemoglobin electrophoresis: This test measures different types of hemoglobin in the blood. It involves using an electric current to separate the hemoglobin in a sample and detect any abnormal hemoglobin.

Blood hemoglobin: This test measures the amount of hemoglobin that exists outside red blood cells.

Differential diagnosis: When a doctor suspects hemoglobin C disease, they may perform other tests to check for similar diseases, such as:

Because hemoglobin C disease usually causes no symptoms, it usually does not require treatment.

People with the disease can develop anemia. If they do, it is mild and rarely interferes with their everyday lives. In some instances, treating chronic hemolytic anemia is necessary.

Hemolysis occurs when the body destroys red blood cells and releases hemoglobin into the bloodstream. This leads to a reduction in folic acid. Taking folic acid supplements can help the body produce more red blood cells and improve anemia symptoms.

The outlook for hemoglobin C disease is good. Most people with the disease have no symptoms and do not need treatment.

If a person with hemoglobin C trait wants to have children, they might consider genetic counseling or blood tests for hemoglobin types. A genetic counselor can also help answer questions about hemoglobin C disease.

Hemoglobin C disease affects the red blood cells. It occurs when a person inherits two copies of hemoglobin C from their parents.

Usually, it requires no treatment. However, some people develop mild anemia and symptoms such as fatigue, weakness, and a fever.