17 Questions
What percentage of people with Down syndrome have trisomy 21?
95%
Approximately how many cases of Down syndrome occur per 10,000 live births in the United States?
9.2 cases
What is the term for a mixture of normal diploid and trisomy 21 cells?
Mosaicism
What is the procedure that confirms the diagnosis of Down syndrome?
Karyotype analysis
What percentage of individuals with Down syndrome have a Robertsonian translocation?
3%
What is the estimated detection rate of trisomy 21 using maternal age and measurement of nuchal translucency?
63 percent
What is the estimated false-positive rate of first-trimester screening by means of maternal age and measurement of nuchal translucency?
5 percent
What is the advantage of chorionic villus sampling over amniocentesis?
Lower risk of maternal morbidity
What is the benefit of using fluorescent in situ hybridization (FISH) in prenatal diagnosis of trisomy 21?
Rapid diagnosis of trisomy 21
How long does karyotype analysis typically require after amniocentesis?
7 to 10 days
What is the benefit of combining first-trimester screening with measurement of maternal serum free betahCG subunit and pregnancy-associated protein A (PAP A)?
Increased detection rate of trisomy 21
What is the primary reason for using ultrasound examination in combination with the triple test?
To reduce the false-positive rate of the triple test
Which of the following ultrasonographic findings is most commonly associated with trisomy 21?
Increased nuchal fold thickness
What is the benefit of using ultrasound measurement of nuchal translucency in first-trimester screening for trisomy 21?
It can reduce the false-positive rate of the triple test
What is the primary advantage of using amniocentesis in pregnant women 35 years or older?
It can detect other chromosomal abnormalities
What is the benefit of using the triple test in combination with ultrasound examination?
It can increase the sensitivity of the triple test
Which of the following is a characteristic of trisomy 21 detected by ultrasound examination?
All of the above
This quiz covers the detection rates of trisomy 21 through various prenatal diagnosis methods, including first-trimester screening and maternal serum measurements.
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