Cytogenetics Overview and Prenatal Analysis
40 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What percentage of spontaneous abortions are associated with chromosomal abnormalities?

  • 25%
  • 33%
  • 50% (correct)
  • 66%

Which condition is characterized by eye fusion, often referred to as Cyclops?

  • Turner Syndrome
  • Klinefelter Syndrome
  • Edward's Syndrome
  • Patau's Syndrome (correct)

What is the most common type of prenatal cytogenetic analysis performed?

  • Chorionic Villus Biopsy
  • Alpha Fetoprotein Test
  • Umbilical Cord Blood Biopsy
  • Amniocentesis (correct)

What is the rate of biological elimination for Trisomy 21?

<p>65% (B)</p> Signup and view all the answers

Which of the following is NOT considered a sex chromosome aneuploidy?

<p>Trisomy 13 (B)</p> Signup and view all the answers

Which condition typically results in a fetal loss during the first trimester?

<p>Trisomy 16 (B)</p> Signup and view all the answers

What percentage of pregnancies recognized with genetic abnormalities will end in spontaneous fetal loss?

<p>15% (A)</p> Signup and view all the answers

What developmental level do babies with Edward's Syndrome typically reach if they survive?

<p>6 months (A)</p> Signup and view all the answers

What is the purpose of prenatal chromosomal analysis?

<p>To screen for possible genetic alterations (A)</p> Signup and view all the answers

Which type of analysis involves collecting amniotic fluid?

<p>Amniocentesis (A)</p> Signup and view all the answers

Which of the following factors increases the incidence of chromosomal abnormalities?

<p>Advanced maternal age (A)</p> Signup and view all the answers

What is a karyotype?

<p>The number of chromosomes and their size distribution (A)</p> Signup and view all the answers

Which condition is caused by a part of the brain protruding through the occipital sutures?

<p>Encephalocele (A)</p> Signup and view all the answers

What is the role of Alpha-fetoprotein (AFP) in prenatal testing?

<p>Marker for chromosomal abnormalities (A)</p> Signup and view all the answers

Which procedure involves sampling tissue from the placenta?

<p>Chorionic Villus Biopsy (A)</p> Signup and view all the answers

What percentage of spontaneous abortions is attributed to prenatal cytogenetic abnormalities?

<p>50%-60% (C)</p> Signup and view all the answers

What is the primary purpose of venous sampling through the cervix?

<p>To sample fetal blood for genetic analysis (C)</p> Signup and view all the answers

What is a common indication for conducting prenatal chromosomal analysis?

<p>Previous child with a chromosomal abnormality (D)</p> Signup and view all the answers

Which of the following techniques is specifically known as cordocentesis?

<p>Umbilical cord blood biopsy (B)</p> Signup and view all the answers

What chromosomal abnormality occurrence percentage applies to newborns who may require postnatal chromosomal analysis?

<p>0.6% - 1.0% (C)</p> Signup and view all the answers

What type of genetic carrier status might prompt chromosomal analysis in a parent?

<p>Carrier of unbalanced gametes (A)</p> Signup and view all the answers

What anomaly can indicate the need for karyotype analysis in a newborn?

<p>Multiple congenital anomalies (D)</p> Signup and view all the answers

Which abnormality is associated with elevated levels of AFP in prenatal screening?

<p>Spinal bifida (C)</p> Signup and view all the answers

What is a chorionic villi's role in prenatal procedures?

<p>It allows genetic analysis via tissue sampling (C)</p> Signup and view all the answers

Which syndrome is characterized by having three copies of chromosome 21?

<p>Trisomy 21 (C)</p> Signup and view all the answers

What is a common heart defect associated with Trisomy 21?

<p>Ventricular septal defects (C)</p> Signup and view all the answers

Which condition is associated with an increased risk in individuals with Klinefelter Syndrome?

<p>Acute Lymphoblastic Leukemia (D)</p> Signup and view all the answers

What is the incidence rate of Trisomy 13, or Patau Syndrome, in live births?

<p>1:4000 to 1:15000 (A)</p> Signup and view all the answers

Which of the following is a feature of Turner Syndrome?

<p>Hypogonadism (D)</p> Signup and view all the answers

Which chromosomal abnormality is most commonly associated with maternal age?

<p>Trisomy 13 (B)</p> Signup and view all the answers

The majority of cases of Trisomy 21 result from what type of genetic event?

<p>Meiotic nondisjunction (D)</p> Signup and view all the answers

Which genetic pattern describes an individual with 46 chromosomes but an additional chromosome 21?

<p>Mosaic type (A)</p> Signup and view all the answers

What is a significant indication for conducting cytogenetic analysis in suspected Down Syndrome cases?

<p>Unexplained mental retardation or developmental delay (D)</p> Signup and view all the answers

What does an abnormal alpha-fetoprotein (AFP) level not necessarily indicate?

<p>Advanced maternal age (C)</p> Signup and view all the answers

What developmental issues are associated with Prader-Willi Syndrome due to loss of function of genes on chromosome 15?

<p>Insatiable appetite and obesity (C)</p> Signup and view all the answers

What is a common characteristic of individuals with anencephaly?

<p>Undeveloped skull with exposed brain (B)</p> Signup and view all the answers

Which of the following disorders is NOT indicated for cytogenetic analysis?

<p>Childhood obesity (C)</p> Signup and view all the answers

During adulthood, which health issue is commonly associated with Prader-Willi Syndrome?

<p>Diabetes mellitus type 2 (B)</p> Signup and view all the answers

Which chromosomal abnormality is typically assessed in cases of Turner Syndrome?

<p>Monosomy X (D)</p> Signup and view all the answers

Which statement regarding alpha-fetoprotein (AFP) testing is true?

<p>It can detect neural tube defects in a significant number of pregnancies. (B)</p> Signup and view all the answers

Flashcards

Aneuploidy

An abnormal number of chromosomes, leading to an imbalance in DNA content.

Karyotype

The complete set of chromosomes in a cell, showing their number and arrangement.

What is the primary reason for prenatal chromosomal analysis?

To identify any potential chromosomal abnormalities that could affect the developing fetus.

Advanced Maternal Age

A pregnancy in a woman over 35 years old, increasing the risk of chromosomal abnormalities in the fetus.

Signup and view all the flashcards

Amniocentesis

A procedure to collect amniotic fluid surrounding the fetus for chromosomal analysis.

Signup and view all the flashcards

Chorionic Villus Biopsy

A procedure to sample tissue from the placenta to analyze fetal chromosomes.

Signup and view all the flashcards

Umbilical Cord Blood

Blood from the umbilical cord can be analyzed for fetal chromosomal abnormalities.

Signup and view all the flashcards

Encephalocele

A rare birth defect where part of the brain protrudes through an opening in the skull.

Signup and view all the flashcards

Cytogenetics

The study of chromosomes and their abnormalities.

Signup and view all the flashcards

Cytogenetic Abnormalities

Changes in the number or structure of chromosomes, leading to genetic disorders.

Signup and view all the flashcards

Prenatal Cytogenetic Abnormalities

Chromosomal abnormalities detected before birth.

Signup and view all the flashcards

Umbilical Cord Blood Biopsy

A prenatal test where blood from the umbilical cord is sampled to analyze fetal chromosomes.

Signup and view all the flashcards

Alpha Fetoprotein (AFP)

A protein in maternal blood, elevated levels may indicate certain fetal abnormalities.

Signup and view all the flashcards

Postnatal Chromosomal Analysis

Chromosomal analysis performed after birth.

Signup and view all the flashcards

Venous Sampling

A procedure to collect blood from a vein, often used in prenatal testing to analyze fetal blood.

Signup and view all the flashcards

Cerebrospinal Fluid (CSF)

Fluid that surrounds the brain and spinal cord, providing protection and nutrients.

Signup and view all the flashcards

Spinal Bifida

A birth defect where the spinal cord doesn't close completely during pregnancy, leading to various neurological issues.

Signup and view all the flashcards

Chorionic Villi Sampling (CVS)

A prenatal test where a sample of chorionic villi (placental tissue) is taken for genetic analysis.

Signup and view all the flashcards

Indications for Prenatal Chromosomal Analysis

Reasons for performing genetic tests during pregnancy, including maternal age, family history, and abnormal ultrasound findings.

Signup and view all the flashcards

Karyotype Analysis

A test that examines the number and structure of chromosomes to identify genetic abnormalities.

Signup and view all the flashcards

Down Syndrome

A genetic disorder caused by an extra copy of chromosome 21, leading to characteristic physical features and developmental delays.

Signup and view all the flashcards

Why is prenatal chromosomal analysis important?

It helps identify potential chromosomal abnormalities in the fetus, like Down Syndrome, early in pregnancy.

Signup and view all the flashcards

What is alpha-fetoprotein (AFP)?

A blood test during pregnancy that checks for neural tube defects like anencephaly, and can also indicate a higher risk of Down Syndrome.

Signup and view all the flashcards

Anencephaly

A severe birth defect where a significant portion of the brain and skull are missing.

Signup and view all the flashcards

Turner Syndrome

A genetic disorder affecting females, caused by a missing or incomplete X chromosome, leading to various physical and developmental characteristics.

Signup and view all the flashcards

Prader-Willi Syndrome

A genetic disorder caused by a loss of function in genes on chromosome 15, characterized by feeding difficulties early on, followed by insatiable appetite and obesity.

Signup and view all the flashcards

What is Fragile X Syndrome?

A genetic disorder affecting mostly males, caused by a mutation in the FMR1 gene, leading to cognitive and physical problems.

Signup and view all the flashcards

Why is cytogenetic analysis used in infertility cases?

Cytogenetic analysis helps identify chromosomal abnormalities in both partners that might contribute to infertility problems.

Signup and view all the flashcards

Trisomy 21

A genetic condition where individuals have three copies of chromosome 21 instead of two. This results in Down Syndrome, the most common chromosomal disorder.

Signup and view all the flashcards

Down Syndrome Characteristics

Individuals with Down Syndrome often exhibit characteristic physical features such as a flat facial profile, upward slanting eyes, single deep crease across the palm, and a protruding tongue. They may also experience intellectual disability and heart defects.

Signup and view all the flashcards

Trisomy 13

A genetic condition caused by the presence of three copies of chromosome 13 instead of two, leading to Patau Syndrome.

Signup and view all the flashcards

Patau Syndrome Characteristics

Individuals with Patau Syndrome often exhibit severe physical anomalies, including microcephaly, cleft lip and palate, polydactyly, and heart defects. They usually have a shorter life expectancy.

Signup and view all the flashcards

Trisomy 18

A genetic condition characterized by three copies of chromosome 18 instead of two, leading to Edwards Syndrome.

Signup and view all the flashcards

Edwards Syndrome Characteristics

Individuals with Edwards Syndrome often experience significant health issues, including heart defects, intellectual disability, small jaw, and clenched fists.

Signup and view all the flashcards

Maternal Age & Aneuploidy

The risk of having a child with aneuploidy (such as Trisomy 21, 13, or 18) increases with advanced maternal age (over 35).

Signup and view all the flashcards

Karyotypic Abnormalities in Trisomy 21

The majority (92.5%-95%) of cases of Trisomy 21 are caused by non-disjunction in parental meiosis, resulting in the karyotype 47,XX+21.

Signup and view all the flashcards

Study Notes

Cytogenetics

  • Cytogenetics studies chromosome structure and abnormalities.
  • Aneuploidy is an abnormal number of chromosomes; usually used to describe abnormal numbers of chromosomes.
  • Karyotype is the number of chromosomes in a normal diploid cell and their size distribution.

Prenatal Cytogenetic Analysis

  • Used to screen for genetic alterations during pregnancy.
  • Common methods: amniocentesis, chorionic villus biopsy, and umbilical cord blood biopsy.
  • Amniocentesis: collects amniotic fluid; chorionic villus biopsy: samples placental tissue; umbilical cord blood biopsy: involves extracting fetal blood.
  • Indications for prenatal testing may include advanced maternal age, multiple pregnancy losses, known family history of genetic disorders, elevated maternal serum screening results, or abnormal ultrasound findings.

Cytogenetic Abnormalities

  • Autosomal trisomies (extra copy of chromosomes 1-22) are a major cause of spontaneous abortions (52%).
  • Trisomy 18 (Edwards syndrome): Babies affected often don't survive past 6 months with a high rate of fetal loss in the first trimester.
  • Trisomy 13 (Patau syndrome): Characterized by striking eye fusion, which is often a critical feature.
  • Trisomy 21 (Down syndrome): Common chromosomal disorder; major cause of mental retardation; incidence of ~1 in 700 live births.
  • Sex chromosome aneuploidies: Include 47,XXX females, 47,XXY males, 47,XXX, Klinefelter syndrome, and Turner syndrome.
  • Klinefelter syndrome (47,XXY): Males with this condition typically have lower than normal levels of testosterone, with possible symptoms such as underdeveloped testes, gynecomastia, and infertility
  • Turner syndrome (45,X): Females with this condition have only one X chromosome; they usually have short stature, developmental delays, and/or heart defects; may have a higher risk of medical conditions throughout their lifetime.
  • Microdeletion syndromes: Include Angelman syndrome and Prader-Willi syndrome.

Prenatal Testing

  • Alpha-fetoprotein (AFP) levels can detect neural tube defects.

Chromosomal Analysis - Postnatal

  • May be indicated for patients with phenotypic abnormalities or diagnosed genetic disorders, or cases of infertility, or multiple spontaneous abortions.

Childhood and Adult Cytogenetics

  • Various tests assess for a broad range of possible issues in patients.

Trisomy 13/Patau Syndrome

  • Incidence of ~1 in 4,000-15,000 live births.
  • Caused by meiotic nondisjunction; associated with maternal age.
  • Key characteristics include microcephaly, mental retardation, microphthalmia, cleft lip/palate, polydactyly, cardiac defects, and renal defects.

Trisomy 18/Edwards Syndrome

  • Incidence of ~1 in 8,000 live births.
  • Due to meiotic nondisjunction, with an association with maternal age.
  • Individuals have low birth weight, mental retardation, micrognathia, prominent occiput, malformed ears, heart defects, and renal malformations, which often lead to death within the first year.

Trisomy 21/Down Syndrome

  • A prevalent chromosomal disorder.
  • Caused by meiotic nondisjunction; associated with maternal age.
  • Major characteristics include growth retardation, broad face, upward-slanting eyes, short nose, short stature, many "loops" on the fingertips, a small and arched palate, a broad hand, prominent palmar crease, intellectual disabilities with an associated IQ range from 20-60, delayed puberty/early menopause, and potential for congenital heart disease or intestinal blockages.

Sex Chromosome Aneuploidies

  • Conditions like Klinefelter syndrome (47,XXY), Turner syndrome (45,X), and XYY syndrome affect both males and females.
  • These conditions typically include various phenotypic features and complications, notably concerning reproductive and developmental outcomes.

Microdeletion Syndromes

  • Prader-Willi syndrome and Angelman syndrome are disorders connected to deletions within chromosome 15.
  • Prader-Willi syndrome is characterized typically by hypotonia, decreased ability to regulate appetite (a major driver of obesity), intellectual disabilities, short stature, other issues.
  • Angelman syndrome features include severe intellectual disability, seizures, jerky movements (ataxia), unusual laughter, and other characteristics.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

Related Documents

Clinical Cytogenetics PDF

Description

This quiz covers the fundamentals of cytogenetics, including chromosome structure, aneuploidy, and karyotype analysis. It also explores prenatal cytogenetic methods like amniocentesis and chorionic villus biopsy, along with the implications of cytogenetic abnormalities. Test your understanding of these critical concepts in genetics.

More Like This

Use Quizgecko on...
Browser
Open
Browser
Browser