Last Updated on November 20, 2025 by Ugurkan Demir
Hereditary anaemia includes many inherited disorders that affect red blood cells. Sickle cell disease is one of the most common and severe. We know how it affects people and their families. We’re dedicated to giving them the care they need.
Sickle cell disease happens when the body makes abnormal hemoglobin S. This causes red blood cells to change shape. This genetic problem can lead to serious health issues. It’s very important to get help from a specialist.
At Liv Hospital, we offer top-notch care for those with these genetic conditions. We aim to provide the best healthcare and support.Learn 7 key facts about hereditary anaemia, including Sickle Cell Disease, gene mutation, and Hemoglobin S. Get the powerful details.
Key Takeaways
- Sickle cell disease is a severe form of hereditary anaemia.
- Abnormal hemoglobin S causes red blood cells to distort.
- Genetic mutation is the underlying cause of sickle cell disease.
- Comprehensive care is key for managing the condition.
- Liv Hospital provides specialized care for international patients.
Understanding Hereditary Anaemia
Hereditary anaemia is a group of genetic disorders affecting the blood. They involve problems with hemoglobin production or function. These conditions are passed down from parents and can greatly affect a person’s life.
Definition and Classification of Inherited Blood Disorders
Hereditary anaemias are divided based on the blood or red blood cell defects. The main types include disorders of hemoglobin structure, like sickle cell disease, and disorders of hemoglobin production, such as thalassemias.
Sickle Cell Disease is a well-known hereditary anaemia. It results from a mutation in the HBB gene, affecting hemoglobin production. This leads to abnormal hemoglobin, known as Hemoglobin S.
Common Types of Hereditary Anaemias
Other notable hereditary anaemias include thalassemia, Fanconi anemia, and Diamond-Blackfan anemia. Each has its own genetic and clinical characteristics.
| Condition | Genetic Defect | Clinical Features |
| Sickle Cell Disease | Mutation in HBB gene | Anemia, pain crises, infections |
| Thalassemia | Mutations in HBA or HBB genes | Anemia, fatigue, bone deformities |
| Fanconi Anemia | Mutations in FA genes | Bone marrow failure, congenital abnormalities |
Knowing about these conditions is key to helping those affected. The diagram of sickle cell disease shows how red blood cells can change shape.
Sickle Cell Disease: A Prevalent Form of Hereditary Anaemia
Sickle cell disease is a common hereditary anaemia worldwide. It affects how red blood cells make hemoglobin, causing health issues.
Global Prevalence: Over 7 Million People Affected
About 7.7 million people worldwide have sickle cell disease. It’s a big health problem. It’s more common in Africa, the Mediterranean, the Middle East, and India.
The disease is linked to malaria. The genetic mutation that causes it also protects against malaria.
Historical Discovery and Terminology
James B. Herrick first described it in 1910. He saw sickle-shaped red blood cells in a patient. This started our understanding of the disease.
The term “drepanocytose” is also used for sickle cell disease. Knowing its history helps us understand it better today.
Understanding sickle cell disease’s global impact and history is key. It shows why we need more research and support for those affected.
The Genetic Basis: Sickle Cell Mutation in the HBB Gene
Sickle cell disease comes from a change in the HBB gene. This gene codes for a part of hemoglobin. The change makes abnormal hemoglobin, called hemoglobin S, which can make red blood cells bend into a sickle shape.
Understanding the HBB Gene Function
The HBB gene tells our bodies how to make a part of hemoglobin. Hemoglobin is key for carrying oxygen. If the HBB gene has a mutation, it can mess up hemoglobin’s job.
Normally, the HBB gene helps hemoglobin work right. But with sickle cell disease, a mutation changes hemoglobin. This change makes red blood cells bend into sickle shapes.
| Gene | Function | Mutation Effect |
| HBB | Codes for beta-globin subunit of hemoglobin | Results in sickle cell disease due to glutamate to valine substitution |
| Normal HBB | Produces normal beta-globin | No disease |
How the Sickle Cell Mutation Occurs
The sickle cell mutation happens because of a single DNA change in the HBB gene. This change makes abnormal hemoglobin S. People need two copies of this mutated gene to have the disease.
The process of mutation involves:
- A single nucleotide substitution in the DNA sequence of the HBB gene.
- The substitution of glutamate with valine at the sixth position of the beta-globin chain.
- The production of abnormal hemoglobin S, which polymerizes under low oxygen conditions, causing red blood cells to sickle.
Knowing how sickle cell disease is caused is key for finding treatments. Doctors can spot the HBB gene mutation. This helps them give families the right advice and care.
Hemoglobin S: The Molecular Basis of Sickle Cell Anaemia
Sickle cell anemia is caused by hemoglobin S, a different type of hemoglobin. This happens because of a genetic mutation. Hemoglobin S is abnormal because of a change in the beta-globin chain. This change makes red blood cells sickle when there’s not enough oxygen.
Normal Hemoglobin vs. Hemoglobin S Structure
Normal hemoglobin (HbA) is made of two alpha-globin chains and two beta-globin chains. Hemoglobin S (HbS) has different beta-globin chains because of the mutation. This change affects how hemoglobin works under different conditions.
Key differences between HbA and HbS include:
| Characteristics | HbA | HbS |
| β-globin chain position 6 | Glu (Glutamic Acid) | Val (Valine) |
| Polymerization under low O2 | No | Yes |
| Red Blood Cell Shape | Normal | Sickled |
How Haemoglobin Sickle Cell Anemia Affects Oxygen Transport
Hemoglobin S polymerizes under low oxygen, making red blood cells sickle. This also makes them less able to carry oxygen. Sickled cells are stiff and break down easily, causing anemia and less oxygen to tissues.
The process of sickling is reversible initially, but repeated episodes cause permanent damage. Knowing how hemoglobin S works is key to finding treatments that help with oxygen transport.
Understanding hemoglobin S and its effects on oxygen transport helps us see the complexity of sickle cell anemia. It shows why we need good management strategies.
The Distinctive Morphology: Sickle Blood Cells
In sickle cell disease, red blood cells lose their normal shape. They become crescent moon or sickle-shaped. This change happens because of a genetic mutation that affects hemoglobin production.
Diagram of Sickle Cell Disease: Visualizing the Abnormal Shape
A diagram helps us see the abnormal shape of red blood cells in sickle cell disease. The change in shape is not just cosmetic. It shows a deep change in the cell’s structure and function.
The sickle shape comes from hemoglobin S polymerizing under low oxygen. This makes the red blood cells rigid and sickle-shaped.
The Process of Sickling and Its Triggers
Sickling is a complex process with several factors. Low oxygen levels are a key trigger, causing hemoglobin S to polymerize. Dehydration also plays a role, increasing hemoglobin S concentration in cells.
Other triggers include infections, stress, and high altitudes. When these triggers cause sickling, red blood cells can get stuck in small blood vessels. This can lead to pain crises and organ damage.
Knowing how sickling works and what triggers it is key to managing sickle cell disease. By avoiding or reducing these triggers, people with the disease can lessen complications.
Clinical Manifestations and Complications
Sickle cell disease shows many symptoms, like pain crises and chronic problems. These issues affect many parts of the body. It’s important to understand them well to care for those with this disease.
Acute Complications: Pain Crises and Emergencies
Pain crises are a big problem in sickle cell disease. They can happen for reasons like dehydration, infection, or cold weather. These crises need quick medical help to manage pain and avoid more harm.
Acute chest syndrome is a serious issue that needs fast treatment. It’s a life-threatening condition.
Handling these crises means fixing the immediate cause and supporting the body. We stress the need for early action and constant watch to lessen the harm.
Chronic Complications and Organ Damage
Long-term problems in sickle cell disease come from repeated blockages and breakdown of red blood cells. Chronic anemia, cardiovascular disease, and kidney damage are common. These issues greatly reduce quality of life and life span.
The reasons behind these long-term issues are complex. They involve sickled red blood cells, endothelial cells, and inflammation. Knowing how these work helps in finding new treatments to stop or lessen organ damage.
Dealing with these long-term issues needs a team effort. Doctors, including hematologists and primary care physicians, work together. They tailor care to meet each patient’s needs.
Genetic Inheritance: What Type of Genetic Disease is Sickle Cell Anemia
It’s important to know how sickle cell disease is inherited. This condition affects how red blood cells make hemoglobin. We’ll look at how it’s passed down and its effects on families.
Autosomal Recessive Inheritance Pattern Explained
Sickle cell disease follows an autosomal recessive pattern. This means a person needs two copies of the HBB gene defect to have the disease. Both males and females have an equal chance of getting it.
If both parents carry the sickle cell trait, there’s a 25% chance their child will have the disease. There’s also a 50% chance the child will carry the trait like the parents. And a 25% chance the child won’t have the disease or carry the trait.
Carrier Status and Sickle Cell Trait
Being a carrier means having one normal and one mutated HBB gene. Carriers usually don’t show the full symptoms but can pass the mutated gene to their kids. They might face health issues under certain conditions.
| Genotype | Phenotype | Carrier Status |
| Normal/Normal | Normal | Not a carrier |
| Normal/Mutated | Carrier | Carrier |
| Mutated/Mutated | Sickle Cell Disease | Not applicable |
Knowing if you’re a carrier is key for family planning. It helps understand the risk of passing the condition to future generations. Genetic counseling is often suggested for carriers to discuss their options.
Variations of Sickle Cell Disease
Sickle cell disease is not just one condition. It’s a range of disorders with different genetic and clinical features. This variety comes from how the sickle cell gene works with other genes that affect hemoglobin.
Sickle Cell Thalassemia and Other Compound Heterozygous States
Sickle cell thalassemia happens when someone has one sickle cell gene and one thalassemia gene. Thalassemia is a group of disorders that affect hemoglobin production. This mix can lead to mild to severe symptoms.
Other compound heterozygous states exist, like hemoglobin SC disease. This occurs when someone has one sickle cell gene and one hemoglobin C gene. These conditions have unique symptoms and challenges.
Different Genotypes and Their Clinical Implications
The genotype of someone with sickle cell disease affects how severe their condition is. Genetic factors like alpha-thalassemia or other hemoglobin variants can change the severity of pain crises and the risk of complications.
The following table summarizes some of the key variations of sickle cell disease and their clinical implications:
| Condition | Genotype | Clinical Features |
| Sickle Cell Anemia | SS | Severe anemia, frequent pain crises, increased risk of infections |
| Sickle Cell Thalassemia | S/β-thalassemia | Variable severity, ranging from mild to severe anemia and pain crises |
| Hemoglobin SC Disease | SC | Milder anemia compared to SS, but at risk for pain crises and complications |
Knowing about the different types of sickle cell disease is key to good care. Healthcare providers can tailor treatments based on each patient’s unique needs by understanding the various genotypes and their implications.
Ethnic Distribution and Population Genetics
Sickle cell disease mainly affects people from Africa, the Mediterranean, the Middle East, and India. This is because these areas used to have a lot of malaria. Malaria and sickle cell disease are linked in a way that protects against malaria.
African, Mediterranean, Middle Eastern, and Indian Prevalence
In sub-Saharan Africa, up to 2% of newborns have sickle cell disease. It’s also common in the Mediterranean, like in Greece and Turkey. In the Middle East and India, certain groups have a higher risk.
| Region | Prevalence of Sickle Cell Disease |
| Sub-Saharan Africa | High (up to 2% of newborns) |
| Mediterranean Region | Moderate to High |
| Middle East | Moderate |
| India | Variable (high in some tribal communities) |
The spread of sickle cell disease is tied to malaria. The sickle cell trait offers some protection against malaria. This is why the gene is more common in malaria areas.
Evolutionary Advantage: Malaria Protection Hypothesis
The malaria protection hypothesis says people with the sickle cell trait (HbAS) have an advantage in malaria areas. This is because they are less likely to get Plasmodium falciparum, the worst malaria parasite.
“The high frequency of the sickle cell gene in certain populations is thought to be due to the protection it affords against malaria, illustrating a classic example of natural selection in humans.”
Research shows kids with the sickle cell trait get less severe malaria. This is why the trait is more common in malaria areas. It’s an evolutionary advantage that keeps the gene around, despite the disease’s harm.
Knowing about sickle cell disease’s spread and genetics helps in making health plans. It also aids in giving genetic advice to affected communities.
Diagnosis and Modern Testing Methods
Diagnosing sickle cell disease involves newborn screening and advanced lab tests. Early detection is key to managing the disease well.
Newborn Screening Programs
Newborn screening is critical for catching sickle cell disease early. A simple blood test is done when the baby is 24 to 48 hours old. Early detection leads to better care for affected kids.
We suggest all newborns get screened for sickle cell disease. This helps doctors watch for and manage problems early on.
Laboratory Tests for Sickle Cell Disease
Several tests diagnose sickle cell disease. Hemoglobin electrophoresis is a main test that spots abnormal hemoglobin, like Hemoglobin S. Other tests include:
- High-performance liquid chromatography (HPLC)
- Isoelectric focusing
- Molecular genetic testing
These tests confirm the diagnosis and show the specific type of hemoglobin.
Genetic Testing and Counseling
Genetic testing finds carriers of the sickle cell gene and helps with prenatal diagnosis. Genetic counseling helps families understand test results and plan for the future.
Genetic counseling is vital for families with sickle cell history. It gives them the info they need to know their risks and options.
Conclusion: Living with Sickle Cell Disease and Future Directions
Sickle cell disease is a complex condition caused by a mutation in the HBB gene. This hereditary anaemia affects millions worldwide. It causes significant morbidity and impacts the quality of life for those affected.
Living with sickle cell disease requires a lot of care and management. Advances in medical care have improved the outlook for individuals with this condition. We see progress in genetic research, giving hope for future treatments.
Future directions for managing sickle cell disease include new therapies. These aim to reduce pain crises and other complications. As research advances, we expect better outcomes for those living with this condition. For more information, visit resources like sickle cell anaemia wikipedia.
FAQ
What is sickle cell disease?
Sickle cell disease is a genetic disorder. It affects the hemoglobin in red blood cells, making them ‘sickle’ shaped. This can cause health problems.
What is the genetic basis of sickle cell disease?
It’s caused by a mutation in the HBB gene. This gene codes for a part of hemoglobin. The mutation leads to abnormal hemoglobin, called hemoglobin S.
How is sickle cell disease inherited?
It’s inherited in an autosomal recessive pattern. A person needs two defective HBB genes, one from each parent, to have the disease.
What is the difference between sickle cell trait and sickle cell disease?
Sickle cell trait means having one normal and one defective HBB gene. People with it are usually healthy but can pass the defective gene. Sickle cell disease means having two defective genes.
What are the clinical manifestations of sickle cell disease?
It can cause acute problems like pain crises and emergencies. It also leads to chronic issues that damage organs.
How is sickle cell disease diagnosed?
It’s diagnosed through newborn screening, lab tests, and genetic testing. Early diagnosis helps manage the disease and prevent complications.
Is there a cure for sickle cell disease?
There’s no cure, but treatments can help manage symptoms and prevent complications. Researchers are working on new treatments.
What is the relationship between sickle cell trait and malaria?
Sickle cell trait may offer some protection against malaria. This is why it’s more common in malaria-prone areas.
Can sickle cell disease be prevented?
It’s a genetic disorder, so prevention isn’t possible. But genetic counseling and testing can help parents understand their risk.
What are the variations of sickle cell disease?
Variations include sickle cell thalassemia and other compound heterozygous states. These have different effects based on the genotype.
How does hemoglobin S affect oxygen transport?
Hemoglobin S can cause red blood cells to sickle and lose oxygen transport ability under low oxygen conditions.
What is drepanocytosis in English?
Drepanocytose is the French term for sickle cell disease. In English, it’s called sickle cell disease or sickle cell anemia.
Reference
- National Heart, Lung, and Blood Institute. (n.d.). What is anemia? https://www.nhlbi.nih.gov/health/anemia
