Which disease affects hemoglobin? A Comprehensive Guide

September 25, 2025 •

4 min read

Over 600 distinct types of inherited blood disorders, known as hemoglobinopathies, affect the hemoglobin protein. Hemoglobin is the vital protein in red blood cells that carries oxygen throughout the body. Knowing which disease affects hemoglobin is crucial for understanding health risks and proper treatment.

Quick Summary

Several diseases impact hemoglobin, with the most common being the inherited hemoglobinopathies, such as sickle cell disease and thalassemia, which cause the body to produce abnormal hemoglobin or not enough hemoglobin. Other conditions, including nutritional and acquired anemias, also affect hemoglobin levels and function.

Key Points

Hemoglobinopathies Defined: Hemoglobinopathies are inherited genetic disorders that cause abnormal hemoglobin structure or production, impacting oxygen transport.
Sickle Cell Disease: This is an inherited disease causing red blood cells to become sickle-shaped, which can block blood flow and lead to pain crises and organ damage.
Thalassemia: This inherited disorder results in the body producing too little hemoglobin, leading to various degrees of anemia depending on the type.
Iron Deficiency Anemia: The most common type of anemia, it occurs when a lack of iron prevents the body from making enough hemoglobin, often due to diet or blood loss.
Aplastic Anemia: A rare condition where bone marrow fails to produce sufficient blood cells, including red blood cells, causing a drop in hemoglobin levels.
Diagnosis is Key: Blood tests like a Complete Blood Count (CBC) and Hemoglobin Electrophoresis are used to diagnose these conditions, with early detection critical for proper management.

Hemoglobinopathies: Inherited Blood Disorders

Hemoglobinopathies are genetic disorders that affect the hemoglobin protein. Hemoglobinopathies impact the structure or production of the hemoglobin molecule, which is essential for oxygen transport. Sickle cell disease and thalassemia are two of the most well-known hemoglobinopathies.

Sickle Cell Disease

Sickle cell disease (SCD) is a group of inherited red blood cell disorders. It is caused by a genetic mutation that results in an abnormal form of hemoglobin, known as hemoglobin S (HbS). Instead of the normal disc shape, red blood cells with HbS become hard, sticky, and crescent or "sickle" shaped when oxygen levels are low. These sickle-shaped cells can get stuck in small blood vessels, blocking blood flow and causing severe pain episodes and organ damage over time.

Types of Sickle Cell Disease

Hemoglobin SS (HbSS): The most common and severe form of SCD, caused by inheriting two copies of the hemoglobin S gene, one from each parent.
Hemoglobin SC (HbSC): A milder form of SCD, resulting from inheriting a hemoglobin S gene and a hemoglobin C gene.
Hemoglobin S Beta Thalassemia: Inherited when a person receives a hemoglobin S gene and a beta thalassemia gene. The severity depends on the specific type of beta thalassemia gene inherited.

Thalassemia

Thalassemia is a group of inherited blood disorders that cause the body to produce less hemoglobin than normal. This reduced production is due to genetic defects affecting the alpha-globin or beta-globin protein chains that make up hemoglobin. The resulting anemia can range from mild to life-threatening, depending on the number and type of genes affected.

Types of Thalassemia

Alpha-thalassemia: Caused by gene defects that reduce or eliminate the production of alpha-globin chains. Severity ranges from silent carriers with no symptoms to the fatal Hemoglobin Barts disease.
Beta-thalassemia: Caused by gene mutations that reduce or eliminate the production of beta-globin chains. Beta-thalassemia major (Cooley's anemia) is the most severe form, requiring lifelong blood transfusions.

Acquired & Other Conditions Affecting Hemoglobin

While hemoglobinopathies are inherited, other conditions can also affect hemoglobin. These are not caused by genetic defects in the hemoglobin protein itself, but rather by external factors impacting red blood cell production or function.

Iron Deficiency Anemia

Iron is an essential component of hemoglobin production. Without enough iron, the body cannot produce a sufficient amount of hemoglobin, leading to iron deficiency anemia. This is the most common form of anemia and can be caused by inadequate dietary intake, blood loss, or malabsorption issues.

Aplastic Anemia

Aplastic anemia is a rare but serious condition where the bone marrow fails to produce enough blood cells, including red blood cells. This leads to a drop in all blood cell counts, including hemoglobin. It can be acquired from viral infections, exposure to toxins, autoimmune diseases, or can be inherited.

Polycythemia Vera

Unlike most conditions that cause low hemoglobin, polycythemia vera results in an overproduction of red blood cells, leading to a high hemoglobin count. This causes the blood to thicken, increasing the risk of blood clots, heart attack, and stroke.

Comparison of Hemoglobin-Affecting Diseases


Feature	Sickle Cell Disease	Thalassemia	Iron Deficiency Anemia	Aplastic Anemia
Cause	Inherited gene mutation for hemoglobin S	Inherited gene mutation/deletion for alpha or beta globin chains	Insufficient iron for hemoglobin production	Bone marrow failure
Effect on Hemoglobin	Abnormal, sickle-shaped hemoglobin protein	Reduced or absent production of normal hemoglobin	Lack of sufficient hemoglobin for red blood cells	Decreased overall hemoglobin production
Red Blood Cell Appearance	Sickle-shaped and stiff	Smaller than normal (microcytic)	Smaller and paler than normal (microcytic, hypochromic)	Normal size and shape, but lower count
Inherited vs. Acquired	Inherited	Inherited	Acquired (diet, blood loss)	Both inherited and acquired

Diagnosis and Management

Diagnosing a disease that affects hemoglobin typically involves a series of blood tests. These include a complete blood count (CBC), which measures the number and quality of red blood cells and hemoglobin levels. Hemoglobin electrophoresis and genetic testing can identify specific hemoglobin disorders. Early diagnosis is essential, especially for inherited conditions, to begin appropriate management and treatment, which can range from lifestyle adjustments to blood transfusions or even bone marrow transplants.

Conclusion

Numerous diseases can affect hemoglobin, altering its structure, production, or quantity. Inherited conditions like sickle cell disease and thalassemia cause significant problems with red blood cell function, while acquired issues such as iron deficiency and aplastic anemia impact the body's ability to produce hemoglobin effectively. Understanding the distinct mechanisms of these diseases is crucial for accurate diagnosis and effective patient care. For comprehensive information and resources on blood disorders, including hemoglobinopathies, visit the American Society of Hematology website [https://www.hematology.org/education/patients/anemia].

Frequently Asked Questions

Both are inherited blood disorders, but they affect hemoglobin differently. Sickle cell disease causes the hemoglobin protein itself to be abnormal, leading to crescent-shaped red blood cells. Thalassemia, however, is a problem with the production of hemoglobin, causing a reduced amount of normal hemoglobin and potentially fewer red blood cells.

Yes, absolutely. The most common example is iron deficiency anemia, where the body lacks the iron needed to produce enough hemoglobin. Deficiencies in other nutrients, such as vitamin B12 and folate, can also lead to anemia and subsequently affect hemoglobin levels.

No, a high hemoglobin count, a condition known as polycythemia, can also indicate a health problem. Conditions like polycythemia vera, a type of blood cancer, or chronic obstructive pulmonary disease (COPD) can cause the body to produce too many red blood cells, which can thicken the blood and lead to complications.

Doctors typically start with a Complete Blood Count (CBC) to measure hemoglobin and red blood cell levels. If abnormalities are found, further tests like hemoglobin electrophoresis can identify specific hemoglobin variants, while genetic testing can confirm inherited disorders.

No, many are not. While conditions like sickle cell disease and thalassemia are inherited, other hemoglobin-affecting diseases like iron deficiency anemia can be acquired through diet, blood loss, or other health issues. Aplastic anemia, a condition of bone marrow failure, can also be either inherited or acquired.

Symptoms can vary greatly depending on the specific disorder and its severity, but common signs often include fatigue, weakness, pale skin, shortness of breath, dizziness, and cold hands and feet. More severe symptoms can include jaundice, pain crises, or organ damage.

For some conditions, like iron deficiency anemia, dietary changes can be a primary treatment. For inherited disorders like sickle cell disease, lifestyle adjustments such as staying hydrated and avoiding extreme temperatures can help manage symptoms. It is always important to consult with a healthcare provider for a proper management plan.