Embryology_Funk.txt

  1. Trisomy 21 (Down Syndrome)
    • 1. Extra copy of chromosome 21. In 75% of cases, occurs as a result of maternal (oocyte) nondisjunction.
    • 2. Growth and mental retardation.
    • 3. Craniofacial defects: brachycephaly, up-slanting palpebral fissures, medial epicanthial folds, small nose with low nasal bridge, small ears.
    • 4. Cardiac defects in approximately 40% of cases: usually septal defects of PDA (patent ductus arteriosus).
  2. Trisomy 18 (Edward syndrome)
    • 1. Extra copy of chromosome 18.
    • 2. Mental retardation
    • 3. Cardiac defects
    • 4. Craniofacial: Low-set ears, micrognathia
    • 5. Clenched fists: flexion of fingers, hands
    • 6. Limited capacity for survival; only about 5-10% live to first year; only handful of case reports of children living to 10 years old.
  3. Trisomy 13 (Patau Syndrome)
    • 1. Extra copy of chromosome 13.
    • 2. Mental retardation;holoprosencephaly
    • 3. Cardiac defects
    • 4. Deafness
    • 5. Craniofacial: Cleft-lip and palate, eye defects
    • 6. Limited capacity for survival; usually only survive 7 days postnally.
  4. Trisomy 8 (Warkany Syndrome)
    • 1. Extra copy of chromosome 8.
    • 2. Mental retardation
    • 3. Long, slender trunk
    • 4. Craniofacial: Prominent forehead, strabismus, micrognathia, cleft palate.
  5. Klinefelter Syndrome; (47, XXY)
    • 1. Extra copy of chromosome X.
    • 2. Male;
    • 3. presence of Barr bodies
    • 4. Sterile, testicular atrophy
    • 5. gynecomastia
  6. f. Turner's Syndrome (45, X)
    • 1. One less copy of X chromosome.
    • -In 80% of cases, paternal nondisjunction.
    • 2. Only monosomy compatible with life.
    • 3. Female
    • 4. Short stature, broad chest, short neck
    • 5. Congenital lymphedema of hands and feet
    • 6. Streak gonads (gonadal dysgenesis)
    • 7. Lack of secondary sex characteristic development at puberty
  7. Duplications of genes
    the result of abnormal genetic crossovers. Duplication abnormalities are rare.
  8. define structural abnormalities
    (deletions, microdeletions, duplications)
  9. Angelman Syndrome (Happy Puppet Syndrome)
    • a.microDeletion on the long arm of chromosome 15.
    • b. maternal chromosome.
    • c. Mental retardation
    • d. Puppet-like gait
    • e. Absent speechProne to unprovoked periods of uncontrolled laughter
  10. Prader-Willi Syndrome
    • a. microDeletion on the long arm of chromosome 15.
    • b. paternal chromosome.
    • c. Mental retardation
    • d. Obesity and hypotonia
    • e. Hypogonadism
  11. Miller-Dieker Syndrome
    • a. Deletion short arm of chromosome 17 b. Lissencephaly (smooth brain), microcephaly
    • c. Severe mental retardation
    • d. Failure to thrive
  12. Microdeletions
    • result from breakage and loss of only a few genes.
    • a. Examples of microdeletions Angelman Syndrome (Happy Puppet Syndrome), Prader-Willi Syndrome, Miller-Dieker Syndrome
  13. Define Deletions
    Breakage and loss of part of a chromosome (viruses, radiation, drugs, etc).

    Examples of deletions 1. Cri-du-chat syndrome (deletion 5p syndrome) Deletion 4q syndrome
  14. Deletion 4q syndrome
    • a. Partial deletion of the long arm of chromosome
    • b. Growth and mental retardation, postnatal onset
    • c. Cleft palate
    • d. Limb abnormalities
  15. Cri-du-chat syndrome (deletion 5p syndrome)
    • a. Partial deletion of the short arm of chromosome
    • b. Characteristic cry of the cat sound due to malformation of larynx
    • c. Growth retardation
    • d. Mental retardation, microcephaly
    • e. Cardiac defects
  16. Numerical Abnormalities
    • Nondisjunction - chromosomes fail to separate during meiotic anaphase, resulting in aneuploidy.
    • 2. The most common aneuploidies are trisomies (one extra copy) or monosomies (one less copy).
    • 3. In women, rate of nondisjunction increases with age (example is for trisomy 21).
    • 15-29 years: 1: 1500
    • 30-34 years: 1: 800
    • 35-39 years: 1: 270
    • 40-44 years: 1: 100
    • Over 45 years: 1: 50
  17. Triple X (47, XXX)
    • 1. Extra copy of chromosome X.
    • 2. Female; two Barr bodies in cells
    • 3. Varying degrees of mental retardation
    • 4. Amenorrheic
    • 5. No classic pattern of malformation
Author
Trinabarr
ID
95979
Card Set
Embryology_Funk.txt
Description
Embryology MCM
Updated