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Foundation Sciences · Genetics
Microdeletion Syndromes
Microdeletion syndromes result from loss of contiguous genes too small to be detected by standard karyotype but seen on FISH or microarray.
📌 Learning Objectives
- Describe the underlying mechanism of Microdeletion Syndromes.
- Identify the key clinical features and complications of Microdeletion Syndromes.
- Outline the appropriate investigations and management of Microdeletion Syndromes.
- Discuss the implications for patients and families of Microdeletion Syndromes.
📋 Overview
Examples include 22q11.2 deletion (DiGeorge), 7q11.23 (Williams), 15q11–13 (Prader–Willi/Angelman) and 5p (Cri du Chat) syndromes. Phenotypes reflect haploinsufficiency of multiple contiguous genes.
🔬 Basic Science
Examples include 22q11.2 deletion (DiGeorge), 7q11.23 (Williams), 15q11–13 (Prader–Willi/Angelman) and 5p (Cri du Chat) syndromes. Phenotypes reflect haploinsufficiency of multiple contiguous genes.
🏥 Clinical Relevance
Genetic counselling is important for recurrence risk estimation.
🧪 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.
microdeletion
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digeorge
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cri du chat
- Microdeletion syndromes are below the resolution of standard karyotyping.
- 22q11.2 deletion causes DiGeorge/velocardiofacial syndrome.
- Williams syndrome (7q11.23) features supravalvular aortic stenosis and a friendly personality.
- CMA is first-line for unexplained developmental delay or multiple congenital anomalies.
- Most microdeletions are de novo rather than inherited.
Exam Pearls ⌄
⭐ High Yield
Microdeletion syndromes are below the resolution of standard karyotyping.
22q11.2 deletion causes DiGeorge/velocardiofacial syndrome.
Williams syndrome (7q11.23) features supravalvular aortic stenosis and a friendly personality.
CMA is first-line for unexplained developmental delay or multiple congenital anomalies.
Most microdeletions are de novo rather than inherited.
💡 Clinical Pearl
Microdeletion: Genetic counselling is important for recurrence risk estimation.
⚠️ Exam Tip — Common Mistakes
Confusing the mechanism of Microdeletion Syndromes with related conditions.
Missing classic clinical features of Microdeletion Syndromes in SBA stems.
Failing to consider Microdeletion Syndromes in the differential diagnosis.
Key Facts ⌄
Microdeletion syndromes are below the resolution of standard karyotyping.
22q11.2 deletion causes DiGeorge/velocardiofacial syndrome.
Williams syndrome (7q11.23) features supravalvular aortic stenosis and a friendly personality.
CMA is first-line for unexplained developmental delay or multiple congenital anomalies.
Most microdeletions are de novo rather than inherited.
Related Topics ⌄
References ⌄
- GMC MLA Content Map
- NICE Clinical Knowledge Summaries
- BMJ Best Practice
Further Resources
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