type

Abnormal chromosome number (example)

detection rate (%)

triploid

8

16

45, X

5

10

16-trisomic

4

8

18-trisomic

3

6

22-trisomic

3

6

13-trisomic

2

4

21-deficiency

1

2

21-trisomic

1

2

47, XXY

1

2