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Foundation Sciences · Genetics
Sickle Cell Disease (Genetics)
Sickle cell disease is an autosomal recessive haemoglobinopathy caused by a point mutation in HBB (Glu→Val) producing HbS, which polymerises on deoxygenation.
📌 Learning Objectives
- Describe the underlying mechanism of Sickle Cell Disease.
- Identify the key clinical features and complications of Sickle Cell Disease.
- Outline the appropriate investigations and management of Sickle Cell Disease.
- Discuss the implications for patients and families of Sickle Cell Disease.
📋 Overview
Sickling causes haemolysis, vaso-occlusive crises, acute chest syndrome, stroke, splenic infarction, priapism and chronic organ damage. Hydroxyurea increases HbF and reduces crises.
🔬 Basic Science
Sickling causes haemolysis, vaso-occlusive crises, acute chest syndrome, stroke, splenic infarction, priapism and chronic organ damage. Hydroxyurea increases HbF and reduces crises.
🏥 Clinical Relevance
Pneumococcal vaccination and prophylactic penicillin reduce infection risk after splenic dysfunction.
🧪 Investigations
Investigation depends on clinical context: relevant blood tests, imaging, and specific genetic or histopathological tests as appropriate. Refer to specialist services where indicated.
💊 Management
Management is condition-specific and typically multidisciplinary, combining medical therapy, surgical intervention where appropriate, supportive care, and family/genetic counselling.
Revision Resources – expand the sections below for high-yield notes, exam pearls, key facts and further reading.
MLA High-Yield Notes & Quick Revision ⌄
Common SBA themes: recognising the underlying mechanism, identifying classic clinical features, and choosing the first-line investigation or management step. Watch for inheritance pattern and characteristic associations.
sickle cell
hbb
hbs
hydroxyurea
vaso-occlusive crisis
- Sickle cell is caused by a Glu6Val mutation in the β-globin (HBB) gene.
- Heterozygotes (HbAS) are usually asymptomatic and protected against malaria.
- Hydroxyurea increases HbF and reduces vaso-occlusive crises.
- Functional asplenia increases risk of encapsulated organisms (pneumococcus, Hib).
- Newborn screening allows early prophylactic penicillin and vaccination.
Exam Pearls ⌄
⭐ High Yield
Sickle cell is caused by a Glu6Val mutation in the β-globin (HBB) gene.
Heterozygotes (HbAS) are usually asymptomatic and protected against malaria.
Hydroxyurea increases HbF and reduces vaso-occlusive crises.
Functional asplenia increases risk of encapsulated organisms (pneumococcus, Hib).
Newborn screening allows early prophylactic penicillin and vaccination.
💡 Clinical Pearl
Sickle Cell: Pneumococcal vaccination and prophylactic penicillin reduce infection risk after splenic dysfunction.
⚠️ Exam Tip — Common Mistakes
Confusing the mechanism of Sickle Cell Disease with related conditions.
Missing classic clinical features of Sickle Cell Disease in SBA stems.
Failing to consider Sickle Cell Disease in the differential diagnosis.
Key Facts ⌄
Sickle cell is caused by a Glu6Val mutation in the β-globin (HBB) gene.
Heterozygotes (HbAS) are usually asymptomatic and protected against malaria.
Hydroxyurea increases HbF and reduces vaso-occlusive crises.
Functional asplenia increases risk of encapsulated organisms (pneumococcus, Hib).
Newborn screening allows early prophylactic penicillin and vaccination.
Related Topics ⌄
References ⌄
- GMC MLA Content Map
- NICE Clinical Knowledge Summaries
- BMJ Best Practice
Further Resources
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