Down Syndrome and Prenatal Diagnosis
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Questions and Answers

What is the name of the trisomy condition characterized by the presence of all or a part of chromosome 18 in the cells of the body three times?

  • Edward syndrome (correct)
  • Down syndrome
  • Patau syndrome
  • Turner syndrome

    • What is the term for the condition where clumps of cysts develop within the kidneys?

  • Klinefelter syndrome
  • Polycystic kidney disease (correct)
  • Ventricular septal defect
  • Trisomy 21

    • What is a characteristic of Trisomy 21, also known as Down syndrome?

  • Mental deficiency
  • Prominent occiput
  • The Simian line (correct)
  • Small testes

    • What is the name of the syndrome characterized by a male person with an extra X chromosome?

    <p>Klinefelter syndrome</p> Signup and view all the answers

    What is the term for the extra fingers or toes that can occur in some individuals with trisomy?

    <p>Polydactyly</p> Signup and view all the answers

    What is the name of the trisomy condition characterized by the presence of all or a part of chromosome 13 in the cells of the body three times?

    <p>Patau syndrome</p> Signup and view all the answers

    What is the term for the heart defect that can occur in individuals with Trisomy 18?

    <p>Ventricular septal defect</p> Signup and view all the answers

    What is the characteristic of Klinefelter syndrome?

    <p>Tall stature with disproportionately long lower limbs</p> Signup and view all the answers

    What percentage of liveborn infants have an obvious major congenital anomaly?

    <p>3%</p> Signup and view all the answers

    What is the primary cause of congenital anomalies according to multifactorial inheritance?

    <p>Combination of genetic and environmental factors</p> Signup and view all the answers

    What is the term for a group of anomalies occurring together due to a common cause?

    <p>Syndrome</p> Signup and view all the answers

    During which period of gestation do malformations typically occur?

    <p>3rd to 8th week</p> Signup and view all the answers

    What is the percentage of Trisomy 21 cases associated with increasing maternal age?

    <p>94 %</p> Signup and view all the answers

    What is the term for the upward slant of the eye fissures?

    <p>Up-slanting palpebral fissures</p> Signup and view all the answers

    What is the term for a condition where a part of the fetus is altered due to mechanical forces?

    <p>Deformation</p> Signup and view all the answers

    What is the term for the crease on the palm of the hand?

    <p>Transverse palmar crease</p> Signup and view all the answers

    What is the result of a vascular accident leading to intestinal atresia?

    <p>Disruption</p> Signup and view all the answers

    What is the term for a condition where certain pairs of chromosomes get an extra chromosome in every cell?

    <p>Trisomy</p> Signup and view all the answers

    What is the term for the bending of the fifth finger towards the fourth finger?

    <p>Incurved fifth finger</p> Signup and view all the answers

    What is the term for the skin folds at the nape of the neck?

    <p>Excessive skin at the nape of neck</p> Signup and view all the answers

    What is the percentage of 2-year-olds with congenital anomalies?

    <p>6%</p> Signup and view all the answers

    What is the term for the unusual flexibility of the joints?

    <p>Hyper flexibility of joints</p> Signup and view all the answers

    What is the term for the small size of the jaw?

    <p>Micrognathia</p> Signup and view all the answers

    What is the term for the extra finger or toe?

    <p>Polydactyly</p> Signup and view all the answers

    Which of the following medications may cause fetal harm?

    <p>All of the above</p> Signup and view all the answers

    What is the primary mechanism by which cocaine may cause birth defects?

    <p>Its role as a vasoconstrictor leading to hypoxia</p> Signup and view all the answers

    Which of the following hormones may cause masculinization of the genitalia of female embryos?

    <p>Androgenic agents</p> Signup and view all the answers

    What is the primary purpose of amniocentesis?

    <p>To diagnose chromosomal abnormalities</p> Signup and view all the answers

    Which of the following maternal diseases may cause a variety of malformations in the fetus?

    <p>Diabetes</p> Signup and view all the answers

    What is the primary purpose of the triple test during prenatal diagnosis?

    <p>To detect Down syndrome</p> Signup and view all the answers

    What is the primary risk associated with maternal consumption of heavy metals during pregnancy?

    <p>Congenital anomalies</p> Signup and view all the answers

    At what gestational age is chorionic villus sampling typically performed?

    <p>10-12 weeks</p> Signup and view all the answers

    What percentage of newborns are born with congenital anomalies?

    <p>5%</p> Signup and view all the answers

    What is the definition of teratogen?

    <p>Any environmental agent that causes damage to the fetus during prenatal period</p> Signup and view all the answers

    What is the effect of rubella on a fetus?

    <p>Cataract, glaucoma, heart defects, and deafness</p> Signup and view all the answers

    What is the mechanism of teratogen?

    <p>Physiological or biological processes that explain the cause or how specific events occur</p> Signup and view all the answers

    What is the effect of ionizing radiation on a fetus?

    <p>It can cause any type of birth defect depending upon dose and stage of development</p> Signup and view all the answers

    What is the effect of thalidomide on a fetus?

    <p>It can cause limb defects and heart malformations</p> Signup and view all the answers

    What is toxoplasmosis?

    <p>An infectious agent</p> Signup and view all the answers

    What is the percentage of males with chromosomal anomalies that have gynecomastia?

    <p>40%</p> Signup and view all the answers

    Study Notes

    Technique of Amniocentesis and CVS

    • Amniocentesis: a prenatal diagnosis technique used to detect chromosomal and metabolic abnormalities, and DNA analysis
    • CVS (Chorionic Villus Sampling): a prenatal diagnosis technique used to detect chromosomal abnormalities, similar to amniocentesis

    Ultrasound Diagnosis

    • Used to detect structural defects in many organs, including:
      • CNS (Central Nervous System)
      • Heart
      • Kidney
      • Limbs
    • Can detect polydactyly (extra fingers/toes), micrognathia (small jaw), and umbilical hernia (associated with Trisomy 18 in 50% of cases)

    Trisomy 21 (Down Syndrome)

    • Caused by an extra copy of chromosome 21 (47, +21)
    • Frequency increases with increasing maternal age (94%)
    • Clinical features include:
      • Brachycephaly (short head)
      • Up-slanting palpebral fissures (eye openings)
      • Epicanthal folds (skin folds at the inner corner of the eyes)
      • Brushfield spots (small white spots on the iris)
      • Flat nasal bridge
      • Folded or dysplastic ears
      • Open mouth
      • Protruding tongue
      • Short neck
      • Excessive skin at the nape of the neck
      • Transverse palmar crease (single palmar crease)
      • Space between the first and second toes
      • Hyper flexibility of joints

    Neonatal Features of Trisomy 21

    • Flat facial profile
    • Dysplasia of pelvis
    • Anomalous ears
    • Excessive skin at the nape of the neck
    • Slanted palpebral fissures
    • Hypotonia (low muscle tone)
    • Hyper flexibility of joints

    Congenital Anomalies (Birth Defects)

    • Definition: structural abnormalities present at birth
    • Causes: genetic, environmental, and multifactorial factors
    • Types of abnormalities:
      • Malformations: occur during organ formation (e.g. cleft lip and palate)
      • Disruptions: result in morphological changes due to exposure to destructive processes (e.g. vascular accidents)
      • Deformations: caused by mechanical forces affecting the fetus (e.g. talipes equinovarus)
      • Syndromes: groups of anomalies occurring together due to a common cause (e.g. Down Syndrome)

    Trisomy

    • Definition: a condition where certain pairs of chromosomes get an extra chromosome in every cell
    • Most common types of trisomy:
      • Trisomy 13 (Patau syndrome)
      • Trisomy 18 (Edwards syndrome)
      • Trisomy 21 (Down syndrome)

    Trisomy 18 (Edwards Syndrome)

    • Caused by an extra copy of chromosome 18
    • Clinical features include:
      • Mental deficiency
      • Growth retardation
      • Prominent occiput
      • Short sternum
      • Ventricular septal defect
      • Micrognathia
      • Low-set malformed ears
      • Flexed digits
      • Hypoplastic nails
      • Rocker-bottom feet

    Other Chromosomal Anomalies

    • Turner syndrome (45,X): a female missing one X chromosome
    • Klinefelter syndrome (47,XXY): a male with an extra X chromosome
    • Structural chromosomal anomalies: include chromosomal deletion, duplication, translocation, inversion, and ring and iso chromosomes

    Teratogens

    • Definition: environmental agents that cause damage to the fetus during the prenatal period
    • Examples: viruses, drugs, chemicals, and radiation
    • Effect: variation in the development of the embryo, fetus, or child
    • Mechanism: the physiological or biological processes that explain the cause or how specific events occur

    Environmental Factors

    • Infectious agents:
      • Viruses (e.g. rubella, cytomegalovirus, herpes simplex, varicella)
      • Toxoplasmosis
      • Syphilis
    • Radiation:
      • Ionizing radiation can kill rapidly proliferating cells, producing any type of birth defect
    • Chemical agents:
      • Thalidomide (produces limb defects and heart malformations)
      • Diphenylhydantoin (produces facial defects and mental retardation)
      • Tetracycline (produces bone and teeth anomalies)
      • Aspirin (may cause harm in large doses)
      • Cocaine (may cause birth defects due to its effect as a vasoconstrictor)
      • Alcohol (causes fetal alcohol syndrome)
    • Hormones:
      • Androgenic agents (cause masculinization of the genitalia of female embryos)
      • Endocrine hormones (e.g. diethylstilbestrol, cause malformation of the uterus, uterine tubes, upper vagina, and vaginal cancer)
      • Insulin (can cause congenital anomalies)
      • Cortisone (in large doses, may cause cleft palate)
    • Maternal disease:
      • Diabetes (can cause variety of malformations, including heart and neural tube defects)
    • Nutritional deficiency:
      • Vitamin deficiencies (particularly)
    • Heavy metals:
      • Organic mercury (can cause birth defects)

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    Congenital Anomalies (Birth Defects) PDF

    Description

    This quiz covers the techniques of amniocentesis and CVS, and the ultrasound features of Down syndrome, including polydactyly, micrognathia, and umbilical hernia. It also discusses the clinical features of Trisomy 21.

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