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  1. autosomes
    non-sex chromosomes, homologous
  2. sex chromosomes
    one pair of the 23, two homologous in females and nonhomologous in males
  3. giemsa stain
    uses banding techniques, unambiguously numbered chromosomes, and individual variation in ch. composition can be studied, and missing or dulication portions often resulting in disease can be identified
  4. karyotype
    ordered display of chromosomes arranged according to size with homologous chromosomes paired together
  5. locus
    area of a chromosome occupied by a gene
  6. alleles
    different forms of a nucleotide sequence
  7. polymorphic
    a locus that has two or more alleles that occur with an appreciable frequency in a population
  8. genotype
    the composition of genes at a given locus
  9. phenotype
    outward appearance of an individual which is the result of both genotype and environment
  10. heterozygote
    effects of one allele mask those of another, dissimilar alleles at corresponding chromosome loci
  11. homozygous
    identical alleles at corresponding chromosome loci
  12. dominant
    allele whose effects are observable
  13. recessive
    allele whose effects are hidden
  14. codominance
    heterozygote is distinguishable from both homozygotes
  15. mode of inheritance
    pattern in which genetic disease is inherited through the generations of a family
  16. principle of segregation
    homologous genes separate from one another during reproduction and that each each reoproductive cell carries only one of the homologous genes
  17. prinicple of independent assortment
    hereditary transmission of one gene has no effect on the transmission of another
  18. chromosomal theory of inheritance
    behavior of chrmomosomes doews essentially correspond to Mendel's laws
  19. pedigree
    tool in analysis of modes of inheritance
  20. proband
    the beginning individual of the pedigree
  21. recurrence risk
    probability that subsequent children also will have the disease
  22. occurence risk
    probability that a child will have the disease
  23. consanguinity
    mating of two related individuals and the offspring are said to be inbred
  24. sex-linked trait
    conditions caused by genes located on the sex chromosomes
  25. sex-influenced trait
    occurs much more often in one sex than in the other
  26. crossing over
    new combinations of alleles can be formed
  27. recombination
    process of forming such new arrangements of alleles
  28. base pair substitution
    one base pair is replaced by another but is subtle and is not observable as chromosome abberations
  29. silent substitution
    amino acid change that does not occur
  30. frameshift mutation
    insertion of deletion of one or more base pairs to the CNA molecule, alters the resulting amino acid sequence
  31. mutagens
    large number of agents known to increase the frequency of mutations
  32. spontaneous mutation
    mutation that occurs in the absence of exposure to known mutagens
  33. mutational hot spots
    certain areas of some chromosomes that have particularly high mutation rates
  34. spontaneous abortions
    50% of all recovered in 1st trimester have major chromosomal abberations
  35. amniocentesis detection method
    • 16 wks
    • fetal fibroblasts cultured for 2-3 wks and karyotyped
    • risk of loss 0.5%
    • only for at risk mothers and fetuses
  36. chorionic villus sampling
    • 10 wk
    • more cells collected and immediately sampled
    • risk 1%
  37. euploid
    multiple of the normal number of chromosomes
  38. polyploid
    • more than the diploid number of ch
    • some normal (liver, bronchial and epithelial) have polyploidy
  39. triploidy
    • three copies of each chromosome
    • early in development and always lethal
  40. aneuploidy
    somatic cell that does not contain a multiple of 23
  41. trisomy
    • three copied of one chromosome
    • may be survivable
    • down's syndrome
  42. monosomy
    • only one copy of a given ch
    • lethal if autosome
    • lethal if no x in male
    • one x in female = turner's
  43. nondisjunction
    • error in which homologous ch or sister ch fail to separate normally during meiosis or mitosis
    • causes monosomy/trisomy
  44. partial trisomy
    • only an extra portion of a chromosome is present in each cell
    • less severe
  45. ch mosaics
    body has two or more different cell lines, each of which has a different karyotype, nondisjunction in 1 line of cells but not the other
  46. nondisjunction can happen when
    meiosis 1 or 2
  47. trisomoy X
    • females having three X ch in each cell
    • sterility, menstrual irregularity, mental
    • more X's = more severe
  48. klinefelters syndrome
    • 47, XXY
    • male appearance
    • sterile
    • half develop female breasts
    • small testes
    • sparse body hair and high voice
    • tall
    • metal retardation
  49. turners syndrome
    • 45,X
    • sterile females
    • gonadal streaks instead of ovaries
    • short and webbing of neck
    • wide nipples
    • carctation of aorta
    • edema of feet
    • reduced carrying angle at the elbow
    • sparse body hair
  50. cri du chat deletion
    • low birth weight
    • mental ret
    • microcephaly
    • heart defects
    • facial appearance and cat cry
  51. duplication
    • less serious than deletion
    • same region of deletion causes mental ret but normal physical characterisitics
  52. inversion
    • balanced, no gain or loss of material
    • inverted order after breaking
    • no apparent physical effect
    • position effect - change in gene's expression cause by its position
  53. translocation
    • interchanging of genetic material between nonhomologous chromosomes
    • lose no important genetic material
    • carriers have no phenotypic differences but offspring will
    • acute myelogenous leukemia
  54. robertsonian translocation
    • fusion of 2 long arms
    • carriers lose no important genetic material
    • offspring have serious duplications/deletions
  55. reciprocal translocation
    • breaks take place in two different chromosomes and material is exchanged
    • carrier is normal
    • offspring have problems
  56. fragile sites
    • areas on chromosomes that develop distinctive breaks and gaps
    • no apparent relationship to disease
  57. hot spot
    repeat of CGG
  58. fragile X syndrome
    • fragile site on long arm of the X ch
    • mental retardation
  59. S&S of fragile X
    • machroordinism
    • mental retardation
    • large ears
    • prominent jaw
    • high pitched jocular speech
  60. Fragile X repeats
    • normal 29
    • 2X - man can carry
    • 4X - man affected and can pass it on
    • >700 - can see phenotype
  61. genetic anticipation
    worse in successive generations
  62. huntington's disease
    • autosomal dominant, hereditary
    • high penetrance
    • neuronal aggregation of defective proteins
    • no cure and few treatments
    • affective more in spermatogenesis
  63. huntington's disease outcome number
    • normal: 17-20
    • 27-35: meiotically unstable
    • 40-50: adult onset cases
    • >50: juvenile onset
  64. demographics of Huntington's
    • inherited through males
    • 1/10000 western countries
    • 5/500000 prevalence
    • all ethnic groups
    • onset 30-50 yo
  65. huntington's patho
    • too many copies of CAG in huntingtin gene
    • in exon 1
    • gain-of-function, negative dominant
  66. huntington's repeat aggregation
    in caudate, putamen, and striatum
  67. problems with huntington's
    • dystonia
    • chorea
    • akinesia
  68. S&S of huntington's
    • fidgetiness, restlessness
    • chorea
    • muscle spasms
    • tics
    • dystonic posturing
    • falling
    • difficulty swallowing/producing speech
    • akinesia
  69. cognitive S&S of huntington's
    • altered organization
    • slowed processing of information
    • difficulty learning new things
    • difficulty planning and prioritizing
    • difficulty multi-tasking
    • impairment of space perception
    • difficulty organizing incoming and outgoing words
  70. executive functions
    • planning, working
    • memory, attention, problem
    • solving, verbal reasoning, inhibition, mental flexibility, multi-tasking,
    • initiation and monitoring of actions
  71. psychiatric S&S of huntington's
    • depression
    • apathy
    • personality changes
    • anxiety/irritability
    • obsession with certain activities
    • delirium/mania
    • dementia
    • denial
  72. treating neurochemical symptoms of huntingtons
    • GABA
    • dopamine antagonists (haloperidol, phenothiazines)
  73. spontaneous mutation
    cause of disease in a child with no family history of the disease
  74. achondroplasia
    • autosomal dominant
    • 7/8 spontateous - mutation of FGFR3
  75. penetrance
    percentage of individuals with a specific genotype who also exhibit the phenotype
  76. age-dependent penetrance example
    • huntington's disease - does not show up until later in life 30-50
    • therefore, penetrance increases with age
  77. incomplete pentrance
    gene is present but normal phenotype
  78. obligate carrier
    person with affected parent and affected child
  79. expressitivity
    • extent of variation in phenotype associated with a particular genotype
    • penetrance can be complete but expressitivity will alter the severity of the phenotype
  80. mechanisms altering expressitivity
    • influenced by other genes
    • environmental factors
    • type of mutation
  81. neurofibromatosis
    • retinoblastoma gene
    • cafe-au-lait or malignant neurofibromas, scoliosis, seizures, gliomas, meuromas, hypertension, learning disabilities
  82. X inactivation
    • turns off one X
    • men have 0 normally
    • women have 1 normally
    • occurs at embryonic 7-14 days
    • can be mom or dad but once inactivated, stable
  83. prader-willi syndrome
    genetic imprinting deletion of ch 15 on fathers side
  84. angelman syndrome
    genetic imprinting deletion of ch 15 on mothers side
  85. S&S of PW
    • short stature
    • obesity
    • hypogonadism
  86. S&S of angelman
    • mental retardation
    • seizures
    • ataxic gait
  87. autosomal recessive
    • need two copies to get the disease
    • carries normal phenotype
    • siblings will have but not parents
    • 1/4 of 2 carrier parents will have
  88. X-linked or mostly (dominant or recessive)
    • recessive
    • hemophilia A and fragile X
  89. sex is determined by...
    SRY gene
  90. XX with SRY =
    male phenotype
  91. XY without SRY
    Female phenotype
  92. most common X-linked...
    • DMD
    • progressive muscle degeneration
    • code for muscle protein and when mutated, doesn't work
  93. cause of death in DMD pts
    respiratory and cardiac failure
  94. male example trait of disease
    male pattern baldness
  95. female examplet trait of disease
    autosomal dominant breat cancer
  96. linkage analysis
    • see how often recombinations of certain genes take place
    • crossing over during meiosis depends on linkage
  97. in situ hybridization
    • . Lab technique to identify certain DNA
    • segments/genes in a large piece of DNA/chromosome
Card Set
patho exam 2
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