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Chapter 5. Clinical Cytogenetics
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In regards to chromosome aneuploidies in humans:
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A. They are rare at the time of conception.
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B. They are seen more often as pregnancy progresses.
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C. If present at conception, they most often end in a miscarriage.
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D. All whole chromosome trisomies are incompatible with postnatal life.
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E. All whole chromosome monosomies are incompatible with postnatal life.
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C is the correct answer. The other answers are incorrect because:
A. Chromosome aneuploidies are not rare at conception. They occur in about 50% of all conceptions.
B. Chromosome abnormalities are frequently lost as miscarriages. The numbers decrease as pregnancy progresses.
C. Trisomy 13, 18 and 21 are compatible with post-natal life.
D. A 45X karyotype is a human monosomy associated with Turner syndrome.
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The incidence of chromosome abnormalities at the time of conception is:
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E is the correct answer. The other answers are incorrect because:
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The incidence of chromosome abnormalities at the time of conception is 50% (1/2).
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A. is the only whole chromosome monosomy seen in live births in humans.
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B. the most common congenital heart disease is a ventricular septal defect.
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D. girls with this condition are usually tall for age.
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E. is more accurately described as Turner's syndrome.
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A is the correct answer. The other answers are incorrect because:
A. Turner syndrome is the only whole chromosome monosomy seen in live births in humans.
B. The most common congenital heart disease in Turner syndrome is coarctation of the aorta.
C. Turner syndrome only occurs in females.
D. Girls with Turner syndrome condition are usually short for age.
E. The apostrophe "s" does not go on the end of an eponym.
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In regards to chromosome disorders in humans:
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A. they occur rarely and are not of major clinical importance.
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B. they may show a paternal age effect.
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C. aneuploidies for the ...