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Foundation Sciences · Genetics
Prader–Willi and Angelman Syndromes (Imprinting)
Prader–Willi and Angelman syndromes both involve 15q11–13 but differ by parent of origin, illustrating genomic imprinting.
📌 Learning Objectives
- Describe the underlying mechanism of Prader–Willi and Angelman Syndromes (Imprinting).
- Identify the key clinical features and complications of Prader–Willi and Angelman Syndromes (Imprinting).
- Outline the appropriate investigations and management of Prader–Willi and Angelman Syndromes (Imprinting).
- Discuss the implications for patients and families of Prader–Willi and Angelman Syndromes (Imprinting).
📋 Overview
Loss of paternal 15q11–13 causes Prader–Willi (hypotonia, hyperphagia, obesity, hypogonadism). Loss of maternal 15q11–13 causes Angelman (severe ID, ataxia, seizures, happy demeanour).
🔬 Basic Science
Loss of paternal 15q11–13 causes Prader–Willi (hypotonia, hyperphagia, obesity, hypogonadism). Loss of maternal 15q11–13 causes Angelman (severe ID, ataxia, seizures, happy demeanour).
🏥 Clinical Relevance
Behavioural management of hyperphagia is central in Prader–Willi syndrome.
🧪 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.
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- Prader–Willi: loss of paternal 15q11–13 contribution.
- Angelman: loss of maternal 15q11–13 (UBE3A gene) contribution.
- Mechanisms include deletion, uniparental disomy and imprinting defects.
- Methylation testing is the first-line diagnostic for both syndromes.
- These syndromes are classic examples of genomic imprinting.
Exam Pearls ⌄
⭐ High Yield
Prader–Willi: loss of paternal 15q11–13 contribution.
Angelman: loss of maternal 15q11–13 (UBE3A gene) contribution.
Mechanisms include deletion, uniparental disomy and imprinting defects.
Methylation testing is the first-line diagnostic for both syndromes.
These syndromes are classic examples of genomic imprinting.
💡 Clinical Pearl
Prader-Willi: Behavioural management of hyperphagia is central in Prader–Willi syndrome.
⚠️ Exam Tip — Common Mistakes
Confusing the mechanism of Prader–Willi and Angelman Syndromes (Imprinting) with related conditions.
Missing classic clinical features of Prader–Willi and Angelman Syndromes (Imprinting) in SBA stems.
Failing to consider Prader–Willi and Angelman Syndromes (Imprinting) in the differential diagnosis.
Key Facts ⌄
Prader–Willi: loss of paternal 15q11–13 contribution.
Angelman: loss of maternal 15q11–13 (UBE3A gene) contribution.
Mechanisms include deletion, uniparental disomy and imprinting defects.
Methylation testing is the first-line diagnostic for both syndromes.
These syndromes are classic examples of genomic imprinting.
Related Topics ⌄
References ⌄
- GMC MLA Content Map
- NICE Clinical Knowledge Summaries
- BMJ Best Practice
Further Resources
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