Chapter 6

  1. What are the primary causes of congenital defects?
    • Genetic factors
    • Environmental factors during embryonic development
    • Affect a quarter of a million infants in US each year, leading cause of infant death
  2. Single gene disorders are caused by a mutant allele, which may be present on either an ____ or the X-or-Y _____ ______.
    autosome, or "sex" chromosome
  3. True/False: A single mutant allele from an affected parent is transmitted to an offspring, depending on the gender of the offspring.
    False. Single mutant allele can affect both genders equally
  4. Marfan Syndrome Characteristics:
    • 75% family origin 25% new mutations
    • 1 in 20,000 people
    • Makes abnormal connective tissue: eyes, heart and blood vessels, skeletal system
  5. Huntington's Disease is an autosomal (dominant/recessive) disorder. List the traits:
    • Dominant
    • Causes brain neurons to degenerate
    • Affects: movement, cognition, and causes psychiatric disorders: dementia, aggressiveness, social withdrawal, mistaken for chronic alcoholism
  6. Cystic fibrosis:
    • Autosomal recessive disorder
    • most common life-threatening genetic disorder in Caucasians (1/25 US Citizens)
    • Abnormal Cl- Transported across epithelium: affects respiratory tract, GI tract, Reproductive tract
  7. Sickle Cell Disease is an autosomal (Dominant/recessive) disorder that...
    • Recessive
    • is an abnormal hemoglobin in RBC
    • chronic hemolytic anemia and blood vessel occlusion
    • No cure
    • Occurs most in persons of African descent because mutant allele is protective against malaria
  8. Phenylketonuria (PKU) is autosomal (dominate/recessive) disorder. Describe:
    • Recessive
    • 1 in 10,000 people
    • Excess phenylalanine cause brain damage
  9. Tay-Sachs Disease is autosomal (dominate/recessive) disorder. Explaine:
    • recessive
    • Predominately in Eastern European Jews
    • Excess ganglioside in lysosome damage brain neurons and retina
    • deterioration of motor and menatl function
    • seziures
    • blindness
  10. X-linked recessive disorders affect which gender most?
  11. Hemophilla A
    • Abnormal coagulation causes bleeding in the soft tissues, GI tract, hip, knee, elbow, and ankle joints
    • Seen more in males -X chromosome
    • From Queen Victoria
  12. Name two common CONGENITAL Multifactorial inheritance disorders
    • Cleft lip/palate
    • Clubfoot
  13. What are some adult multifactorial inheritance disorders? (More often due to genetics and environment)
    • Coronary artery disease
    • Diabetes mellitus
    • Hypertension
    • Cancer (some forms)
    • Bipolar disorder and schizophernia
  14. Structural Chromosomal Disorder: Cri Du Chat ("cry of cat") syndrome
    • Deletion of segment from chromosome #5
    • Small head and unusual features
    • Mewing sound present in newborn
    • Children have feeding problems
    • Often die in infancy
  15. Aneuploidy
    • zygote that has an abnormal chromosome number
    • results in spontaneous abortions
  16. Polysomy individuals:
    • have more than two of one type of chromosome
    • XXY or XXXY
    • Klinefelter syndrome
  17. Trisomy individuals:
    • Have one extra chromosome for one type of chromosome
    • extra number 21 chromosome
    • Down's syndrome
  18. Monosomy individual:
    • only one chromosome (not a pair) for one type of chromosome
    • One less X chromosome
    • Turner's Syndrome
  19. Klinefelter Syndrome
    • Male born with more than one X chromosome
    • Small testes and inability to produce sperm
    • Low testosterone levels during puberty
    • 1 in 500 to 1 in 1000 male births
  20. Turner's Syndrome:
    • Female born with only one X chromosome
    • Short in stature
    • webbing of neck
    • absence of ovaries, no menstruation
    • visuospatial organization
    • attention deficit problems
  21. What is the most common chromosomal disorder?

    A. Down's syndrome
  22. True/False: Risk of down syndrome increases with the age of the mother
    • True
    • 1 in 25 if mother is over 45
  23. Down Syndrome
    • aka Trisomy 21
    • Short stature
    • Small square head
    • Epicanthal fold of eyes
    • Slanted eyes
    • Mental retardation
    • Heart defects
    • Prone to Alzheimer's
  24. What are some known causes of congenital disorders or malformations?
    • Diabetes melitus
    • smoking
    • Alcohol
    • Measles and rubella viruses
    • Taxoplasma gondii
    • Radiation
  25. What is a teratogenic agent?
    An environmental agent that produces abnormalities during embryonic or fetal development
  26. What are some teratogenic agents?
    • Radiation
    • Chemicals and drugs: alcohol-fetal syndrome, anticoagulants(warfarin), Cancer drugs(aminopterin, methotrexate)
    • Infectious agents: viruses, bacteria, protistans
  27. Fetal Alcohol Syndrome (FAS)
    • Harmful effects extend throughout pregnancy
    • Changes facial features, growth deficits, CNS abnormalities
Card Set
Chapter 6
Genetic and Congenital Disorders