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Table 1 Published cases of false negative NIPT results due to chromosome 21q;21q rearrangements

From: A rare Down syndrome foetus with de novo 21q;21q rearrangements causing false negative results in non-invasive prenatal testing: a case report

Case number

cfDNA screening technology

Indication for NIPT

Pregnant woman age (yrs)

Blood drawn at GA (wk + d)

Fetal DNA fraction

Z-score for T21

Karyotype

Explanation for false negative NIPT result

Study [reference]

1

MPSS

1/370 risk for T21 by serum screening

32

18 + 0

15.6%

2.04

46,XX,der(21;21)(q10;q10),+ 21

Placental biopsies had 17–53% with T21 mosaicism

Wang et al. (2013) [7]

2

MPSS

Not recorded

26

25

13.4%

Normal

46,XY,der(21;21)(q10;q10),+ 21

Not recorded

Zhang et al. (2015) [14]

3

tMPS

Not recorded

Not recorded

Not recorded

Not recorded

Normal

46,XN,der(21;21)(q10;q10),+ 21

Not recorded

Willems et al. (2016) [24]

4

MPSS

1/140 risk for T21 by serum screening

34

13 + 5

10.5%

0.68

46,XX,i(21)(q10)

Confirmed iso21q; placental trisomy mosaicism confirmed

Oepkes et al. (2016) [25]

5

MPSS

Not recorded

Not recorded

10 + 6

7%

0.63

46,XX,der(21;21)(q10;q10),+ 21

21q rearrangement (presumed iso21q); placenata not available for study

Huijsdens-van Amsterdam et al. (2018) [23]

6

MPSS

1/300–1/700 for T21 by serum screening

Not recorded

12 + 3

3%

0.83

46,XX,i(21)(q10)

Confirmed iso21q; placental not available for study

Huijsdens-van Amsterdam et al. (2018) [23]

7

tMPS

Ultrasound markers

Not recorded

23 + 0

17.2%

Normal

46,XX,der(21;21)(q10;q10),+ 21

21q rearrangement (presumed iso21q); placenata not available for study

Huijsdens-van Amsterdam et al. (2018) [23]

8

tMPS

Ultrasound markers

Not recorded

13 + 0

12.7%

Normal

46,XX,der(21;21)(q10;q10),+ 21

21q rearrangement (presumed iso21q); placenata not available for study

Huijsdens-van Amsterdam et al. (2018) [23]

9

MPSS

1/592 risk for T21 by serum screening

30

17 + 5

16.9%

0.66

46,XY,der(21;21)(q10;q10),+ 21

Placenata not available for study

This study

  1. Notes: cfDNA = cell-free DNA; GA = gestational age; iso21q = isochromosome 21q; MPSS = Massive Parallel Shotgun Sequencing; NIPT = Non-Invasive Prenatal Testing; T21 = Trisomy 21; tMPS = targeted Massive Parallel Sequencing