Demographic data. From April 2016 to December 2022, 4211 women underwent invasive prenatal genetic diagnosis in our center. Among them, 169 cases (169/4211,4%) underwent chorionic villus and 4042 cases (4042/4211,96%) underwent amniocentesis. Clinical indications include only advanced maternal age (467/4211,11.09%), high-risk maternal serum screening (832/4211, 19.76%), high risk of NIPT (573/4211,13.6%), abnormal ultrasound (1379/4211, 32.75%) and other indications(960/4211,22.80%), such as intrauterine growth retardation, history of adverse pregnancy or family history, maternal request, in vitro fertilization, drug use or exposure to toxic substances during pregnancy, consanguineous marriage, and parental anxiety. The mean gestational age was 12 weeks (11-13) for chorionic villus and 20 weeks (16-30) for amniocentesis.
Table 1 CMA results of 4211 cases with different indications for prenatal diagnosis
Subgroups
|
Total
|
Normal
|
Abnormal
|
Common Autosomal Aneuploidies
|
Rare Autosomal Aneuploidy
|
Sex Chromosome Aneuploidy
|
CNVs(P/LP)
|
CNVs(VUS)
|
|
|
|
|
|
|
|
|
T21
|
T18
|
T13
|
|
|
|
|
|
|
AMA- only
|
467(11.09%)
|
437(93.58%)
|
30(6.42%)
|
6(1.28%)
|
2(0.43%)
|
|
|
2(0.43%)
|
11(2.35%)
|
9(1.93%)
|
|
Abnormal MSS
|
832(19.76%)
|
782(94.00%)
|
50(6.00%)
|
6(0.72%)
|
5(0.6%)
|
|
2(0.24%)
|
3(0.36%)
|
21(2.52%)
|
13(1.56%)
|
|
Abnormal NIPT
|
573(13.60%)
|
349(60.91%)
|
224(39.09%)***
|
16(2.79%)
|
3(0.53%)
|
2(0.35%)
|
7(1.22%)
|
122(21.29%)
|
49(8.55%)
|
25(4.36%)
|
|
Abnormal ultrasound
|
1379(32.75%)
|
1252(90.79%)
|
127(9.21%)
|
34(2.47%)
|
17(1.23%)
|
1(0.07%)
|
1(0.07%)
|
8(0.58%)
|
49(3.55%)
|
17(1.24%)
|
|
Others
|
960(22.80%)
|
911(94.90%)
|
49(5.10%)
|
3(0.31%)
|
2(0.21%)
|
|
1(0.1%)
|
2(0.21%)
|
29(3.02%)
|
12(1.25%)
|
|
Total
|
4211
|
3731(88.6%)
|
480(11.4%)
|
65(1.54%)
|
29(0.69%)
|
3(0.07%)
|
12(0.29%)
|
136(3.23%)
|
159(3.78%)
|
76(1.8%)
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
***The significance is at the p < 0.001 level.
From April 2016 to December 2022, a total of 4211 samples were analyzed by whole chromosome microarray, and the results of 480 samples were abnormal (480/4211,11.4%), including 245 cases of chromosomal numerical abnormality (245/4211, 5.82%) and 235 cases of CNVs abnormality (235/4211)((see Table 1 and Figure 1). Among 245 cases of chromosomal numerical abnormality, 65 cases were trisomy 21 (65/4211, 1.54%), trisomy 18 (29/4211,0.69%) and trisomy 13 (3/4211,0.07%). 7 cases of rare autosomal abnormalities, including 3 cases of trisomy 2, 2 cases of trisomy 9, 1 case of trisomy 16, 1 case of trisomy 22, 1 case of trisomy 4 and 1 case of trisomy 13. There were 136 cases (136/4211,3.23%) of sex chromosome aneuploidy. 64 cases (64/235,27.2%) of parents were analyzed by CMA, )of which 47 cases (47/235,20%) were parental inheritance and 17 cases (17/235,7.2%) were de novo mutation. Of the 235 CNV abnormalities, 159 cases (159/4211,3.78%) were P/LP (See Schedule 1), and 76 cases (76/4211,1.80%) were VUS (See Schedule 2). In different clinical diagnosis group, Rate of abnormal diagnosis in abnormal NIPT is significantly higher than that in the other four clinical indication groups (P<0.001). Rate of abnormal diagnosis in abnormal ultrasound is significantly higher than others(9.21% vs 5.10%,P< 0.001). There was no significant difference between the other two groups(p>0.05).
AMA only. The pregnant women in this group are only over 35 years old and have no other indications, with an average age of 39.3 years (35-53 years old). There were 30 cases (30/467, 6.42%) of chromosomal abnormality detected by CMA, including 10 cases of aneuploidy (10/467, 2.14%) and 20 cases of CNV abnormalities (20/467, 4.28%). 467 AMA patients were divided into three subgroups according to maternal age (see Table 2), and the relationship between maternal age and chromosomal abnormality rate was analyzed. The aneuploidy rate was positively correlated with increasing age, while CNVs did not have this growth trend.
Table 2 CMA results of 467 pregnant women with only AMA
Subgroups
|
35-39
|
40-44
|
≥45
|
gamma value
|
P
|
Normal
|
229(93.85%)
|
182(93.33%)
|
26(92.86%)
|
-
|
-
|
Abnormal
|
15(6.15%)
|
13(6.67%)
|
2(7.14%)
|
0.047
|
0.866
|
Aneuploidy
|
3(1.23%)
|
6(3.08%)
|
1(3.57%)
|
0.392
|
0.289
|
CNVs(P/LP)
|
7(2.87%)
|
4(2.05%)
|
0(0%)
|
-0.26
|
0.878
|
CNVs(VUS)
|
5(2.05%)
|
3(1.53%)
|
1(3.57%)
|
-0.009
|
0.608
|
Abnormal MSS results. The center screened the serum of pregnant women in the second trimester by detecting the levels of AFP and free β-HCG. 832 cases of abnormal MSS were analyzed by CMA, and 50 cases (50/832, 6.00%) were abnormal, including 16 cases of aneuploidy (16/832, 1.92%) and 34 cases of CNVs (34/832,4.08%). 832 cases with abnormal MSS were divided into three subgroups according to risk types: 721 cases with high risk of trisomy 21 syndrome (721/832, 86.66%), 28 cases with high risk of trisomy 18 syndrome (28/832, 3.36%) and 83 cases with intermediate risk of trisomy 21 syndrome (83/832, 9.98%). Among them, 6 cases were trisomy 21 syndrome, all of which were high risk of 21 trisomy syndrome. There were 5 cases of trisomy 18, of which 4 cases showed high risk of trisomy 21 syndrome and 1 case showed high risk of trisomy 18 syndrome (see Table 3). There are 2 cases of rare autosomal aneuploidy, one 1 case of trisomy 4 mosaicism and 1 case of trisomy 16 mosaicism.
Table 3 CMA results of 832 pregnant women with abnormal MSS
Subgroups
|
Total
|
Normal
|
Abnormal
|
T21
|
T18
|
Sex Chromosome Aneuploidy
|
Rare Autosomal Aneuploidy
|
CNVs(P/LP)
|
CNVs(VUS)
|
|
High risk of trisomy 21 syndrome(≥1/270)
|
721(86.66%)
|
678(94.04%)
|
43(5.96%)
|
6(0.83%)
|
4(0.55%)
|
2(0.28%)
|
2(0.28%)
|
19(2.63%)
|
10(1.39%)
|
|
High risk of trisomy 18 syndrome(≥1/350)
|
28(3.36%)
|
25(89.29%)
|
3(10.71%)
|
|
1(3.57%)
|
1(3.57%)
|
|
|
1(3.57%)
|
|
Intermediate risk of trisomy 21 syndrome(1/270-1/1000)
|
83(9.98%)
|
79(95.18%)
|
4(4.82%)
|
|
|
|
|
2(2.41%)
|
2(2.41%)
|
|
total
|
832
|
782(94.00%)
|
50(6.00%)
|
6(0.72%)
|
5(0.60%)
|
3(0.36%)
|
2(0.24%)
|
21(2.52%)
|
13(1.56%)
|
|
Abnormal NIPT results. We used CMA to evaluate 573 cases of NIPT abnormalities (including chromosomal aneuploidy and CNVs detected by NIPT) A total of 224 cases of chromosomal abnormalities were detected (224 / 573,39.09 % ), including 159 cases of aneuploidy ( 150 / 573,26.18 % ), 7 cases of ROH ( 7 / 573,1.22 % ), and 67 cases of CNVs ( 67 / 573,11.69 % ). The 573 cases with abnormal NIPT results were divided into 5 subgroups according to different chromosomal abnormalities. In the abnormal chr21 group, there were 16 cases of trisomy 21 and 1 case of CNVs among the 23 high-risk populations with trisomy 21. In the abnormal chr18 group, there were 3 cases of trisomy 18 and 8 cases of CNVs among 22 high-risk populations with trisomy 18. In the abnormal chr13 group, there were 3 cases of trisomy 13 and 3 cases of CNVs among 12 high-risk populations with trisomy 13 Among 235 cases with high risk of other autosomal abnormalities, 54 cases (54/235,23.0%) were detected, including 6 cases of aneuploidy (6/235, 2.55%), including 1 case of trisomy 16 mosaicism, 1 case of trisomy 22 mosaicism, 3 cases of trisomy 2 mosaicism, 1 case of trisomy 9 mosaicism, 6 cases of ROH ( 6 / 235,2.55 % ), 42 cases of CNVs ( 42 / 235,17.87 % ). Among 281 cases of sex chromosome abnormality, 122 cases of sex chromosomal aneuploidy, 1 case of ROH and 13 cases of CNVs were confirmed by CMA. (see Table 4). In addition, the positive diagnosis rate of chr21 was significantly higher than that of other autosomal abnormalities (73.9% vs 22.98%, p < 0.001), and the positive diagnosis rate of sex chromosome abnormality was also significantly higher than that of other autosomal abnormalities (48.04% vs 22.98%, p < 0.001).
Table 4 CMA results of 573 pregnant women with abnormal NIPT
Subgroups
|
Total
|
Normal
|
Abnormal
|
Aneuploidy
|
ROH
|
CNVs(P/LP)
|
CNVs(VUS)
|
T21
|
23(4.01%)
|
6(26.09%)
|
17(73.91%)
|
16(69.57%)
|
|
|
1(4.35%)
|
T18
|
22(3.84%)
|
11(50.00%)
|
11(50.00%)
|
3(13.64%)
|
|
8(36.36%)
|
|
T13
|
12(2.09%)
|
6(50.00%)
|
6(50.00%)
|
3(25.00%)
|
|
2(16.67%)
|
1(8.33%)
|
Other autosomes
|
235(41.01%)
|
181(77.02%)
|
54(22.98%)
|
6(2.55%)
|
6(2.55%)
|
28(11.91%)
|
14(5.96%)
|
Sex chromosomes
|
281(49.04%)
|
145(51.06%)
|
136(48.04%)
|
122(43.42%)
|
1(0.36%)
|
11(3.91%
|
2(0.71%)
|
Total
|
573
|
349(60.91%)
|
224(39.09%)
|
150(26.18%)
|
7(1.22%)
|
49(8.55%)
|
18(3.14%)
|
Abnormal ultrasound. 1379 cases of fetal abnormalities were examined by ultrasound. and 127 cases (127/1379,9.21%) were found by CMA analysis, including 61 cases of chromosomal aneuploidy (61/1379, 4.42%) and 66 cases of CNV abnormalities (66/1379,4.79%). According to the characteristics of ultrasound, 1379 cases of ultrasound abnormalities were divided into five subgroups. multiple (more than two ) structural abnormalities in 27 cases (1.96 %, 27 / 1379), single system structural abnormalities in 447 cases (32.41 %,447 / 1379 ), single ultrasound soft marker abnormalities in 774 cases (56.13 %, 774 / 1379 ), multiple ( more than two ) ultrasound soft marker abnormalities in 70 cases (5.08 %, 72 / 1379), structural abnormalities combined with soft marker abnormalities in 61 cases (4.42 %,61 / 1379 ). In general, the chromosomal abnormality rate of multi-system structural abnormalities group was the highest (18.52%5/27), followed by structural abnormality combined with ultrasound soft marker abnormality group (16.39%,10/61), multiple ultrasound soft marker groups(10%,7/70)and single ultrasound soft marker abnormality group (75/779,9.69%). In the subgroup of single-system structural abnormalities, cardiovascular system abnormalities were the most common (39.15 %, 175 / 447), and CMA detected 5.71 % (10 / 175) of chromosomal abnormalities. The second was Genito-urinary system abnormalities (91 / 447,20.35 %), CMA detected 5.49 % ( 5 / 91 ) of chromosomal abnormalities. In this study, the detection rate of chromosomal abnormalities in the Musculoskeletal system was the highest (19.05 %, 4 / 21 ), followed by Central nervous system abnormalities ( 15.15 %, 5 / 33 ).In the subgroup of single ultrasound soft marker abnormality, the most common abnormality is thickened nuchal translucency (29.07%,225/774), chromosome abnormality accounted for 18.22 % ( 41 / 225 ), followed by Choroid plexus cyst ( 16.41 %, 127 / 774 ), chromosome abnormality accounted for 7.09 % ( 9 / 127 ). However, in this study, the detection rate of chromosomal abnormalities with Renal echogenicity enhancement was the highest (28.57 %, 2 / 7 ), followed by nuchal cystic hygroma ( 22.22 %, 8 / 36 ) ( see Table 5 ).
Table 5 CMA results of 1379 pregnant women with ultrasound abnormalities
Subgroups
|
Total
|
Normal
|
Abnormal
|
Common Autosomal Aneuploidies
|
Sex Chromosome Aneuploidy
|
Rare Autosomal Aneuploidy
|
CNVs(P/LP)
|
CNVs
(VUS)
|
|
|
|
|
T21
|
T18
|
T13
|
|
|
|
|
Abnormality of a single ultrasonic soft marker
|
774(56.13%)
|
699(90.31%)
|
75(9.69%)
|
26(3.36%)
|
10(1.29%)
|
1(0.13%)
|
5(0.65%)
|
1(0.13%)
|
24(3.10%)
|
8(1.03%)
|
Thickened nuchal translucency
|
225(16.32%)
|
184(81.78%)
|
41(18.22%)
|
16(7.11%)
|
6(2.67%)
|
1(0.44%)
|
2(0.89%)
|
|
12(5.93%)
|
4(1.78%)
|
Aplasia/Hypoplasia of the nasal bone
|
29(2.10%)
|
28(96.55%)
|
1(3.45%)
|
|
|
|
|
|
1(3.45%)
|
|
Intracardiac echogenic focus
|
48(3.48%)
|
48(100%)
|
|
|
|
|
|
|
|
|
Persistent left superior vena cava
|
12(0.87%)
|
12(100%)
|
|
|
|
|
|
|
|
Ventriculomegaly
|
104(7.54%)
|
97(93.27%)
|
7(6.73%)
|
4(3.85%)
|
|
|
|
|
2(1.92%)
|
1(0.96%)
|
Single umbilical artery
|
29(2.10%)
|
27(93.10%)
|
2(6.90%)
|
|
|
|
|
1(3.45%)
|
1(3.45%)
|
Choroid plexus cyst
|
127(9.21%)
|
118(92.91%)
|
9(7.09%)
|
2(1.57%)
|
3(2.36%)
|
|
|
|
3(2.36%)
|
1(0.79%)
|
Echogenic bowel
|
45(3.26%)
|
44(97.78%)
|
1(2.22%)
|
|
|
|
|
|
1(2.22%)
|
Enlarged posterior fossa
|
14(1.02%)
|
14(100%)
|
|
|
|
|
|
|
|
|
Renal echogenicity enhancement
|
7(0.51%)
|
5(71.43%)
|
2(28.57%)
|
|
|
|
|
|
2(28.57%)
|
|
Polyhydramnios
|
38(2.76%)
|
37(97.37%)
|
1(2.63%)
|
|
|
|
|
|
1(2.67%)
|
|
Oligohydramnios
|
10(0.73%)
|
9(90.00%)
|
1(10.00%)
|
|
|
|
|
|
1(10%)
|
Nuchal cystic hygroma
|
36(2.61%)
|
28(77.78%)
|
8(22.22%)
|
4(11.11%)
|
1(2.78%)
|
|
3(8.33%)
|
|
|
|
Aberrant subclavian artery
|
50(3.63%)
|
48(96.00%)
|
2(4.00%)
|
|
|
|
|
|
|
2(4.00%)
|
Abnormality of multiple
ultrasonic soft markers
|
70(5.08%)
|
63(90.00%)
|
7(10.00%)
|
1(1.43%)
|
|
|
2(2.86%)
|
|
3(4.29%)
|
1(1.43%)
|
Structural anomaly in a single system
|
447(32.41%)
|
417(93.29%)
|
30(6.71%)
|
4(0.90%)
|
2(0.45%)
|
|
1(0.22%)
|
|
15(3.35%)
|
8(1.79%)
|
Cardiovascular system
|
175(12.69%)
|
165(94.29%)
|
10(5.71%)
|
2(1.14%)
|
|
|
|
|
6(3.43%)
|
2(1.14%)
|
Musculoskeletal system
|
21(1.52%)
|
17(80.95%)
|
4(19.05%)
|
|
|
|
1(4.76%)
|
|
2(9.52%)
|
1(4.76%)
|
Pleural abnormalities
|
46(3.34%)
|
46(100%)
|
|
|
|
|
|
|
|
|
Genito-urinary system
|
91(6.60%)
|
86(94.51%)
|
5(5.49%)
|
|
|
|
|
|
2(2.20%)
|
3(3.30%)
|
Abdominal abnormalities
|
49(3.55%)
|
43(87.76%)
|
6(12.24%)
|
2(4.08%)
|
1(2.04%)
|
|
|
|
2(4.08%)
|
1(2.04%)
|
Faciocervical system
|
13(0.94%)
|
13(100%)
|
|
|
|
|
|
|
|
|
Vascular malformations
|
7(0.51%)
|
7(100%)
|
|
|
|
|
|
|
|
|
Central nervous system
|
33(2.39%)
|
28(84.85%)
|
5(15.15%)
|
|
1(3.03%)
|
|
|
|
3(9.09%)
|
1(3.03%)
|
Sacrococcygeal teratoma
|
12(0.87%)
|
12(100%)
|
|
|
|
|
|
|
|
|
Structural anomaly in
multiple systems
|
27(1.96%)
|
22(81.48%)
|
5(18.52%)
|
1(3.70%)
|
2(7.41%)
|
|
|
|
2(7.41%)
|
|
Structural anomaly
combined with soft marker
abnormalities
|
61(4.42%)
|
51(83.61%)
|
10(16.39%)
|
2(3.28%)
|
3(4.92%)
|
|
|
|
5(8.20%)
|
|
Total
|
1379
|
1252(90.79%)
|
127(9.21%)
|
34(2.47%)
|
17(1.23%)
|
1(0.07%)
|
8(0.58%)
|
1(0.07%)
|
49(3.55%)
|
17(1.24%)
|
Other indications. Other indications of prenatal examination, such as (intrauterine growth retardation, history of adverse pregnancy or family history, maternal request, in vitro fertilization, drug use or exposure to toxic substances during pregnancy, consanguineous marriage, and parental anxiety). Among 960 cases of other indications, CMA results showed that 8 cases (0.83%,8/960) had chromosomal aneuploidy and 41 cases (4.27%,41/960) had CNV abnormalities (see Table 1). Among 960 cases with other indications, there were 633 cases with adverse pregnancy or family history, including 6 cases with chromosome aneuploidy (0.95%,6/633,) and 22 cases with CNVs abnormality (6.47%,22/633). Among 120 cases of intrauterine growth retardation, 5 cases were CNVs(P/LP) and 2 cases were CNVs(VUS). Five cases of CNVs with obvious clinical significance included 1 case of 5q23.2q35.3 duplication with Xq23q28 deletion, 1 case of 16p11.2 deletion syndrome, 2 cases of Wolf-Hirschhorn syndrome and 1case of 13q31.1q32.1 deletion.
Detection of ROH by CMA platform. In this study, we used CMA to detect 11 cases of ROH ((see Schedule 2), including 1 case of the whole X chromosome, 1 case of the whole chromosome 4, 2 cases of the long arm fragment of chromosome 15, 1 case of the short arm fragment of chromosome 16, 2 cases of the partial fragment of chromosome 8, 1 case of the short arm fragment of chromosome 5, 1 case of the long arm fragment of chromosome 12 and 8.
Pregnancy follow-up outcome. A total of 4211 pregnant women were followed up (see Table 6). Among 3731 pregnant women with normal CMA results, 3568 cases (3568 / 3731,95.63 % ) were normal after birth, and 100 cases were terminated for various reasons (100/3731, 2.68%), Among them, 56 cases were induced by abnormal ultrasound structure, 11 cases were fetal death, 11 cases were accidental abortion, 4 cases were induced by monogenic disease, 5 cases were mosaicism of karyotype results, 4 cases were placental abruption, 9 cases did not want to induce labor for personal reasons. 45 cases (45 / 3731,1.21 %) of fetal abnormalities occurred after birth. The most common abnormality was cardiac structural abnormalities (15 / 45,33.33 %), followed by death after birth (5 / 45,11.11 %).45 cases (45/3731, 1.21%) had fetal abnormalities after birth. The main abnormality was cardiac structural abnormality (15/45, 33.33%), followed by death after birth (5/45, 11.11%). Among the 404 pregnant women with CNVs (P / LP), 332 (332 / 404,82.18 %) terminated pregnancy and 70 (70 / 404,17.33 % ) continued pregnancy. Among them, 65 (65 / 404,16.09 % ) fetuses were normal after birth, and 5 ( 5 / 404,1.24 % ) fetuses were abnormal after birth. These 5 abnormalities included 1 case of post-natal death caused by trisomy 2 mosaicism, 3 cases of ichthyosis, 1 case of atrial septal defect and ventricular septal defect. Among 76 pregnant women with VUS, 30 (30/76,39.47%) chose to terminate their pregnancy, and 45 (45/76,59.21%) chose to continue their pregnancy. Among them, 44 (44/76,57.89%)fetuses were normal after birth, and 1(1/76,1.32%) fetus was abnormal after birth (six fingers in the right hand). Follow-up information of 21 pregnant women was refused, 18 cases had normal CMA results, 2 cases had CNVs(P/LP) results and 1 case had VUS results.
Table 6 Follow-up results of 4211 pregnant women tested for CMA
CMA results
|
Total
|
Normal child after birth
|
Induced delivery
|
Abnormal child after birth
|
Refuse
|
Normal
|
3731(88.60%)
|
3568(95.63%)
|
100(2.68%)
|
45(1.21%)
|
18(0.48%)
|
CNVs(P/LP)
|
404(9.59%)
|
65(16.09%)
|
332(82.18%)
|
5(1.24%)
|
2(0.49%)
|
CNVs(VUS)
|
76(1.81%)
|
44(57.89%)
|
30(39.47%)
|
1(1.32%)
|
1(1.32%)
|
Total
|
4211
|
3677(87.32%)
|
462(10.97%)
|
51(1.21%)
|
21(0.50%)
|