Questions and Answers
What is DiGeorge Syndrome caused by?
A mutation in the TBX1 gene
What is the frequency of DiGeorge Syndrome in the general population?
1 in 4000
What is the percentage of cases of DiGeorge Syndrome that experience seizures?
40%
Who first described DiGeorge Syndrome?
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What is the percentage of cases of DiGeorge Syndrome that have scoliosis?
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What is the location of the gene deletion that causes DiGeorge Syndrome?
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What is the percentage of cases of DiGeorge Syndrome that have hearing deficits?
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What is the term for the similar syndrome described by Dr. Robert Shprintzen?
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What is a limitation of G-banding in evaluating 22q11.2 deletion?
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What is the primary indication for performing Chromosomal Microarray (CMA)?
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What is the advantage of using FISH in detecting 22q11.2 deletion?
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Why is genetic testing of parents essential in cases of 22q11.2 deletion?
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What is the increased risk associated with germline mosaicism?
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What is the importance of identifying chromosome 22 abnormalities in parents?
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Which of the following methods is most frequently used to detect the 22q11.2 deletion?
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What is the advantage of Chromosomal Microarray (CMA) over G-banding?
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Why is it recommended to suggest genetic testing to parents of affected individuals?
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What is the limitation of G-banding in evaluating 22q11.2 deletion?
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What is the primary indication for performing Chromosomal Microarray (CMA)?
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What is the advantage of using FISH in detecting 22q11.2 deletion?
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Why is genetic testing of parents essential in cases of 22q11.2 deletion?
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What is the increased risk associated with germline mosaicism?
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What is the primary reason why DiGeorge syndrome affects many parts of the body?
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How did the discovery of the deletion in the q arm of chromosome 22 impact the understanding of DiGeorge syndrome and velocardiofacial syndrome?
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What is the significance of the TBX1 gene in DiGeorge syndrome?
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What is the common link between DiGeorge syndrome and velocardiofacial syndrome?
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What is the psychological impact of DiGeorge syndrome on patients?
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Study Notes
DiGeorge Syndrome
- DiGeorge syndrome is an autosomal dominant microdeletion syndrome located on chromosome 22 at 22q11.21.
- The main gene deletion that causes DiGeorge syndrome is TBX1, but other genes may be involved.
- DiGeorge syndrome affects approximately 1 in 4000 people.
Developmental Effects
- Failures in developing pharyngeal pouches during embryonic development lead to multiple bodily defects.
- 40% of cases have seizures.
- 47% of cases have scoliosis.
- 28% of cases have hearing deficits.
Mental Health Risks
- Increased risk of being diagnosed with ADD and bipolar disorder.
- Schizophrenia affects 22% of patients.
Discovery and Identification
- Dr. Angelo DiGeorge first described DiGeorge syndrome in the 1960s, noting a pattern of anomalies in infants.
- Dr. Robert Shprintzen described a similar syndrome, velocardiofacial syndrome, around the same time.
- In 1981, it was discovered that DiGeorge syndrome is caused by a deletion in the q arm of chromosome 22.
- FISH studies with fluorescent probes were conducted in 1992 to determine submicroscopic deletions.
Diagnostic Methods
- G-Banding: incapable of revealing microdeletions in the 22q11.2 region.
- Chromosomal Microarray (CMA): most individuals with a 22q11.2 deletion are identified using CMA.
- FISH: frequently used to detect the 22q11.2 deletion, with customizable probes to determine deletion size.
Genetic Testing and Recurrence Risk
- Genetic testing of parents of affected individuals is essential to determine whether the condition results from inheritance or de novo.
- If occurring de novo, there is a slight increased recurrence risk due to germline mosaicism.
- If abnormalities associated with chromosome 22 are detected in parents, it suggests an increased recurrence risk in future pregnancies.
DiGeorge Syndrome
- DiGeorge syndrome is an autosomal dominant microdeletion syndrome located on chromosome 22 at 22q11.21.
- The main gene deletion that causes DiGeorge syndrome is TBX1, but other genes may be involved.
- DiGeorge syndrome affects approximately 1 in 4000 people.
Developmental Effects
- Failures in developing pharyngeal pouches during embryonic development lead to multiple bodily defects.
- 40% of cases have seizures.
- 47% of cases have scoliosis.
- 28% of cases have hearing deficits.
Mental Health Risks
- Increased risk of being diagnosed with ADD and bipolar disorder.
- Schizophrenia affects 22% of patients.
Discovery and Identification
- Dr. Angelo DiGeorge first described DiGeorge syndrome in the 1960s, noting a pattern of anomalies in infants.
- Dr. Robert Shprintzen described a similar syndrome, velocardiofacial syndrome, around the same time.
- In 1981, it was discovered that DiGeorge syndrome is caused by a deletion in the q arm of chromosome 22.
- FISH studies with fluorescent probes were conducted in 1992 to determine submicroscopic deletions.
Diagnostic Methods
- G-Banding: incapable of revealing microdeletions in the 22q11.2 region.
- Chromosomal Microarray (CMA): most individuals with a 22q11.2 deletion are identified using CMA.
- FISH: frequently used to detect the 22q11.2 deletion, with customizable probes to determine deletion size.
Genetic Testing and Recurrence Risk
- Genetic testing of parents of affected individuals is essential to determine whether the condition results from inheritance or de novo.
- If occurring de novo, there is a slight increased recurrence risk due to germline mosaicism.
- If abnormalities associated with chromosome 22 are detected in parents, it suggests an increased recurrence risk in future pregnancies.
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