Lecture 14 Flashcards

1
Q

Pseudoautosomal region

A

Regions of X Y chromosome that match. Line up during meiotic recombination

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2
Q

X-linked recessive

A
  • more severe in male
  • skipped generations
  • no male to male transmission
  • daughters of affected father are carriers
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3
Q

Recurrence risk for X-linked recessive if mother is carrier

A

Daughter: 50% carrier, 50% normal
Son: 50% affected, 50% normal

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4
Q

6 x-linked recessive disorders

A
-dystrophin associated muscular dystrophy
    DMD
    Becker muscular dystrophy
-G6PD deficiency
-Hemophilia A and B
-Lesch-Nyhan syndrome (HGPRT deficiency)
-Red-green color blindness
-x-linked SCID
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5
Q

X-linked dominant 4

A
  • predominantly female
  • no male to male
  • affected male transmits to all his daughters
  • variable expressivity
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6
Q

Y-linked disease 3

A
  • mutations in the SRY genes
  • H-Y histocompatibility antigen
  • hairy ears
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7
Q

Reduced penetrance

A

Same as incomplete dominance, may complicate an autosomal dominant

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8
Q

Locus heterogeneity 5 diseases

A
  • osteogenesis imperfecta: defect in collagen, mutations of chromosome 17 or chromosome 7
  • sensorineural hearing impairment
  • retinitis pigmentosa
  • Charcot Marie Tooth disease (AD, AR, x-linked)
  • SCID (AR, x-linked)
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9
Q

Variable expression reasons 3

A

Random chance
Other genetic factors or sex influence
Environmental exposure

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10
Q

Variable expression diseases 4

A

Hemochromatosis (AR)
Xeroderma pigmentosum (AR)
CF (AR)
Embryonic development disorder

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11
Q

Germline mosaicism

A

Mutant sperm in testis

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12
Q

Pleitropy

A

A disease causing mutation affects multiple organ systems

  • Marfan syndrome (AD)
  • osteogenesis imperfecta
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13
Q

Delayed age of onset 3

A

Huntington disease (AD)
Hemochromatosis
Familial breast cancer (BRCA-1 or BRCA-2 mutation)

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