Podcast
Questions and Answers
What is the most common type of trisomy found in live born infants?
What is the most common type of trisomy found in live born infants?
Which chromosomal disorder is associated with monosomy of a sex chromosome?
Which chromosomal disorder is associated with monosomy of a sex chromosome?
What type of structural chromosomal aberration involves the loss of a chromosome segment?
What type of structural chromosomal aberration involves the loss of a chromosome segment?
Which trisomy condition is characterized by severe developmental issues and is less common than Down syndrome?
Which trisomy condition is characterized by severe developmental issues and is less common than Down syndrome?
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What does aneuploidy refer to in genetic terms?
What does aneuploidy refer to in genetic terms?
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Which of the following is not a type of numerical chromosomal aberration?
Which of the following is not a type of numerical chromosomal aberration?
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What defines aneuploidy in chromosomal terms?
What defines aneuploidy in chromosomal terms?
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A ring chromosome results from which type of structural chromosomal change?
A ring chromosome results from which type of structural chromosomal change?
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Which type of cellular condition is characterized by a total of 47 chromosomes?
Which type of cellular condition is characterized by a total of 47 chromosomes?
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Which of the following conditions is most likely characterized by a lack of one sex chromosome?
Which of the following conditions is most likely characterized by a lack of one sex chromosome?
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Which chromosomal aberration results from the loss of one chromosome?
Which chromosomal aberration results from the loss of one chromosome?
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Which of the following conditions is considered a viable trisomy?
Which of the following conditions is considered a viable trisomy?
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What defines polyploidy?
What defines polyploidy?
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Which aberration describes the duplication of a chromosome segment?
Which aberration describes the duplication of a chromosome segment?
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Which type of chromosomal abnormalities may involve one or more autosomes?
Which type of chromosomal abnormalities may involve one or more autosomes?
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Which of these is a double set of chromosomes resulting in a total of 92?
Which of these is a double set of chromosomes resulting in a total of 92?
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What type of chromosome abnormality is characterized by a mirror image copy of a chromosome segment including the centromere?
What type of chromosome abnormality is characterized by a mirror image copy of a chromosome segment including the centromere?
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Which type of translocation involves the exchange of segments between two different chromosomes?
Which type of translocation involves the exchange of segments between two different chromosomes?
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In which chromosomes does Robertsonian translocation typically occur in humans?
In which chromosomes does Robertsonian translocation typically occur in humans?
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What is the primary clinical indication for requesting a cytogenetic analysis?
What is the primary clinical indication for requesting a cytogenetic analysis?
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What is the karyotype notation for a normal male?
What is the karyotype notation for a normal male?
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What chromosomal condition results from having an abnormal number of chromosomes?
What chromosomal condition results from having an abnormal number of chromosomes?
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Which type of aneuploidy involves the presence of an extra chromosome?
Which type of aneuploidy involves the presence of an extra chromosome?
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Which of the following is an example of monosomy?
Which of the following is an example of monosomy?
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Study Notes
Trisomy
- Trisomy 21, or Down Syndrome, is the most common trisomy in live-born infants.
Genetic Causes of Down Syndrome
- Numerical chromosomal anomalies are most common in humans.
- Trisomy 21 (Down Syndrome), Trisomy 18 (Edward Syndrome), and Trisomy 13 (Patau Syndrome) are all trisomies found in humans.
Monosomy
- Monosomy occurs when only one chromosome exists in a pair.
- All complete autosomal monosomies are lethal early in development.
- Sex chromosome monosomies can be viable, with Turner Syndrome (45, X) being an example.
Turner Syndrome
- Turner Syndrome occurs in females with a single X chromosome (45, X).
- Individuals with Turner Syndrome present with short stature and unique neck features.
Chromosomal Aberrations
- Aberrations in chromosomes can be either numerical or structural.
- Numerical aberrations are: Aneuploidy, Polyploidy.
- Structural aberrations are: Deletion, Duplication, Translocation.
Aneuploidy
- Aneuploidy is the most common and clinically significant type of chromosome disorder.
- Meiotic nondisjunction is the most common cause of aneuploidy.
- Trisomy and monosomy are the most common aneuploidies.
Nondisjunction
- Nondisjunction is a failure of homologous chromosomes to separate properly during meiosis.
Trisomy
- Trisomy is the gain of one chromosome.
- Chromosomes 13, 18, 21, X, and Y are viable for whole chromosome trisomies.
Isochromosome
- An isochromosome is a mirror image copy of a chromosome segment including the centromere.
Translocation
- Translocation involves the transfer of a portion of one chromosome to another chromosome.
- Robertsonian Translocation: The attachment of an entire chromosome to another chromosome at the centromere. This only happens with acrocentric chromosomes 13, 14, 15, 21, and 22.
- Reciprocal Translocation: The exchange of segments from two different chromosomes.
Cytogenetic Diagnostic Techniques
- Clinical cytogenetics studies chromosomes, their structure, and inheritance.
- Chromosome analysis is a diagnostic tool used in various areas of clinical medicine.
- Genome analyses, including chromosomal microarrays and whole genome sequencing (WGS), offer improved capacity and resolution.
Clinical Indications for Cytogenetic Analysis
- Problems with early growth and development.
- Stillbirth and neonatal death.
- Fertility issues.
- Family history of chromosomal abnormalities.
- Pregnancy in older women.
Conventional Karyotype
- A karyotype is a photomicrograph of individual chromosomes arranged in a standard manner.
- Living nucleated cells undergoing division can be used for studying human chromosomes, such as circulating lymphocytes, amniocytes, and bone marrow.
What Abnormalities Can Be Detected With Conventional Karyotyping
- Aneuploidy: The gain or loss of entire chromosomes.
- Large Deletions: Loss of a substantial portion of a chromosome.
- Duplications: Extra copies of a specific chromosome region.
- Translocations: The transfer of genetic material between chromosomes.
- Inversions: Segments of chromosomes that are reversed in orientation.
- Ring Chromosomes: A chromosome that forms a ring due to a break and rejoining of a chromosome's ends.
- Isochromosomes: Chromosomes that are mirror images of each other.
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Description
Explore the fascinating world of chromosomal abnormalities, focusing on trisomy conditions such as Down Syndrome, Turner Syndrome, and more. This quiz delves into the genetic causes, implications, and types of chromosomal aberrations. Test your knowledge on aneuploidy and the viability of various chromosomal configurations.
