The traditional cytogenetic karyotyping and its adjunct method fluorescence in situ hybridization (FISH) have been used to detect chromosomal abnormalities in many clinical settings. Here we evaluated their accuracy in a University hospital in China. Cytogenetic analysis was used to detect 23 pairs of chromosomes and FISH analysis was carried out to examine chromosomes 13, 18, 21, X, and Y. In 2930 cases, 2928 cases generated karyotype results and 193 cases are abnormal karyotypes (including 114 cases of chromosomal numerical abnormality and 79 cases of structural chromosomal abnormality). FISH analysis confirmed 114 cases of chromosomal numerical abnormality. Karyotyping coupled with FISH can make rapid and accurate diagnosis of chromosomal aberrations. Therefore, our data is helpful in studying relationships between genetic disorders, especially the chromosomal abnormalities with possible birth defects in Zhejiang Province, China.

1. Evaluation of the accuracy of FISH plus conventional fetal karyotyping in a University Hospital in China
IJGOR
Evaluation of the accuracy of FISH plus conventional
fetal karyotyping in a University Hospital in China
Hongge Li1,#
, Qiyin Zhou2,#
, Songchang Chen3
, Yuqin Luo1
, Ling Pan1
, Yeqing Qian1
,
Chenming Xu1,3*
1
Ministry of Education Key Laboratory of Reproductive Genetics, Department of Reproductive Genetics, Women's
Hospital, Zhejiang University School of Medicine, Hangzhou 310006, China
2
Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou 310029, China
3
The International Peace Maternity & Child Health Hospital, Shanghai Jiao Tong University School of Medicine, China
#
These authors contributed equally to this work.
The traditional cytogenetic karyotyping and its adjunct method fluorescence in situ
hybridization (FISH) have been used to detect chromosomal abnormalities in many clinical
settings. Here we evaluated their accuracy in a University hospital in China. Cytogenetic
analysis was used to detect 23 pairs of chromosomes and FISH analysis was carried out to
examine chromosomes 13, 18, 21, X, and Y. In 2930 cases, 2928 cases generated karyotype
results and 193 cases are abnormal karyotypes (including 114 cases of chromosomal numerical
abnormality and 79 cases of structural chromosomal abnormality). FISH analysis confirmed 114
cases of chromosomal numerical abnormality. Karyotyping coupled with FISH can make rapid
and accurate diagnosis of chromosomal aberrations. Therefore, our data is helpful in studying
relationships between genetic disorders, especially the chromosomal abnormalities with
possible birth defects in Zhejiang Province, China.
Keywords: Prenatal detection; chromosomal abnormalities, amniotic fluid; chromosome karyotype; fluorescence in situ
hybridization (FISH)
INTRODUCTION
Chromosomal abnormalities, with an incidence of 1 in
160 births, are one of the major causes of birth defects in
China and lead to genetic burden on the society, along
with psychological and economical pressure on families.
Moreover, there are no curative treatments for them so
far (Chen et al., 2011; Dai et al., 2011; Dan et al., 2012).
Chromosomal aneuploidies of 13, 18, 21, X, and Y
account for the majority of newborn chromosomal
abnormalities (Neagos et al., 2011; Ho et al., 2012).
Therefore, it is of key importance for the diagnosisof fetal
chromosomal aberrations.
Non-invasive techniques such as ultrasound and
maternal serum biochemical scanning measure
epiphenomena related with chromosomal aneuploidies,
rather than directly detecting the core pathology.
Consequently, these approaches have limited sensitivity
and specificity (Chen et al., 2011; Ho et al., 2012).
Recently, the PCR technology based non-invasive fetal
testing (NIPT) has enabled the detection of trisomies of
13, 18, and 21 with acceptable performance and has
been introduced into the clinical settings of USA and
China (Chen et al., 2011; Dan et al., 2012; Ho et al., 2012;
Lo YM. 2012; Song et al., 2013; Zhou et al., 2014; Rossi
and Berghella, 2014).
*Corresponding author: Chenming Xu, Ph.D.
Department of Reproductive Genetics, Women's
Hospital, Zhejiang University School of Medicine, 1
Xueshi Road,Hangzhou, Zhejiang 310006, China. Tel.:
+86-571-89991860, E-mail: chenming_xu2006@163.com
International Journal of Gynecology and Obstetrics Research
Vol. 2(2), pp. 012-017, August, 2015. © www.premierpublishers.org. ISSN: 1407-8019x
Research Article

2. Evaluation of the accuracy of FISH plus conventional fetal karyotyping in a University Hospital in China
Li et al. 012
However, it is worth of noting that in our hospital, the
positive cases of the NIPT as well as pregnancies with
familial history, medical history or other reasons are
advised to have invasive procedure diagnosis including
prenatal fetal karyotyping (Zhou et al., 2014).
The conventional cytogenetic banding of metaphase
chromosomes in cultured amniotic fluid amniocytes is the
golden standard for the detection of numerical and
structural chromosomal aberrations (Lo YM. 2012;
Jobanputra et al., 2002; kale et al., 2014). In addition,
rapid aneuploidy detection (RAD) methods such as
fluorescence in situ hybridization (FISH), which
enumerate chromosomes 13, 18, 21, X, and Y of
interphase chromosomes from uncultured amniotic fluid
amniocytes usually completes within 48h, has been
regarded as an adjunct method of karyotyping and it is
now wide spread used (Ho et al., 2012; Jia et al., 2011;
Elsayed et al., 2013).
Here, we assessed the performance of karyotyping and
FISH in 2930 pregnant women in our hospital, which
locates in Zhejiang Province, China, and mainly reviewed
their roles in prenatal diagnosis
MATERIALS AND METHODS
Patients
From May 2012 to December 2013, the amniocentesis
was performed in 2930 pregnant women, whose maternal
age varied from 18 to 49, at the Women’s Hospital,
Zhejiang University School of Medicine. The study was
approved by the Ethics Committee of the University
hospital and all individuals participating in the study
provided written informed consent before the invasive
procedure. Indications used to classify high-risk
pregnancies as advanced maternal age (35 years old or
beyond) (n=1032), positive maternal serum screen for
Down syndrome (n=1530), ultrasound abnormalities
(n=65), previous child with chromosomal abnormalities
(n=207), and others (n=96).
Sample collection
During the second trimester (18-24 weeks),
amniocentesis was performed by the certificated
physicians under ultrasound guidance. 25-30ml amniotic
fluid was obtained from each pregnant woman, 20ml of
amniotic fluid was reserved for cytogenetic analysis, and
5-10 ml of amniotic fluid for FISH analysis.
FISH probe kit
The VysisAneuVysion Multicolor DNA probe kit (Illinois,
USA) including locus-specific identifier probe (LSI) that
detect 13q14 (RB1 gene) and 21q22.13-q22.2 (D21S259,
D21S341, D21S342) regions of chromosomes 13 and 21,
and centrometric enumeration probes (CEP) that detect
alpha satellite sequences in the centromere regions of
chromosomes 18 (D18Z1), X (SXZ1), and Y (DYZ3),
respectively.
Cytogenetic analysis
Two parts of amniocytes were cultured in BIOAMF-2
medium independently for each patient from 20 ml
amniotic fluid in 5% CO2 incubator at 37℃ for 6-7 days.
Then prewarmed colchicine (20μg/ml) was added to the
culture medium and further incubated for 3-4 hours.
Prewarmed Trypsin-EDTA solution was added for
digestion followed by centrifugation at 1000 rpm for 10
min for cell pellet. After the treatment of 0.075M Kcl low
permeability solution at 37℃ for 5min the fixed solution
(Volume ratio of methanol: glacial acetic acid =3:1) was
added for 30min. The fixed cells were added to the glass
and baked at 80℃ for 90min. G-banding on all the
samples was performed as described elsewhere
(Jobanputra et al., 2002). 20-30 random metaphase
spreads were evaluated for each case. Karyotypes were
as previously described (Jin et al., 2011).
FISH analysis
5-10ml sample amniotic fluid was used for FISH assay as
described elsewhere (Eiben et al., 1998). Fish view expo
4.0 systems is used to analyze result by Olympus AX70
fluorescence microscope with four kinds of filter with red,
green, sky blue, and blue. Each hybrid-zone counts about
100 cells, which background and signal are clear:
1)probe CEP18/CEPX/CEPY: Displayed 2 blue, 1 green,
1 red signal in the nuclei of normal male, and 2 blue, 2
green signal in the nuclei of normal female; 2) probe
LSI13/LSI21: In normal cells display 2 green signal, 2 red
signals.
Report delivery and posttest counseling
Karyotyping results were obtained within 2 to 3 weeks
and FISH reports were finalized within 3 working days
from sample collection. The report included the fetal
aneuploidies of chromosomes 13, 18, 21, X, and Y. Fetal
sex was not reported according to the Law on Maternal
and Infant Health of China. Posttest counseling was
provided for all study participants and clinicians advised
each individual based on the outcome of the test results.
In addition, the follow-up investigation was performed to
document the phenotype of the neonates and comparing
this with results of the antenatal karyotype and FISH
analysis as previously described (Dan et al., 2012).
RESULTS
Conventional chromosome analysis
Among 2930 amniotic fluid samples, 2 cases without

3. Evaluation of the accuracy of FISH plus conventional fetal karyotyping in a University Hospital in China
Int. J. Gynecol. Obstet. Res. 013
Table 1. Chromosomal abnormality in the cytogenetic study
Numerical chromosomal
abnormality
Structural chromosomal abnormality
Karyotype
Case
s
Karyotype Cases Karyotype Cases
47,XN,+21 68 46,XN,inv(9) 34 46,X,t(X;16)(p22;p12) 1
47,XN,+18 21 46,XN,5p- 2 46,XN,t(2;16)(p21,q21) 1
47,XN,+13 2 46,XN,9p- 1 46,XN,der(21;22) (q10;q10) 1
47,XXY 9 46,X,inv(Y) 2 46,XN,der(14;21) (q10;q10) 1
47,XYY 3 46,XN,inv(4) 1 46,XN,del(3)(p24) 1
47,XXX 3 46,XN,inv(2)(p23;q23) 1 46,XN,del(9)(p23) 1
45,X 5 46,XN,inv(7)(p14;q21) 1 46,X,t(X;3) (p22;q29) 1
45,X/46,XX 1 46,XY,t(Y;21) 2 46,XN,t(7;11)(p22,p23) 1
69,XXX 1 46,XN,t(8;18) 1 46,XN,der(7)t(3;7)(q25;q32) 1
47,XN,inv(9),+21 1 46,XN,t(7;11) 1 46,XN,t(5;20) (q23;q13.3) 1
46,XN,t(1:2:4) 1 46,XN,t(11;15) (q23; p10) 1
46,XN,t(11;16) 1 46,XN,t(9;14) (p12 ;q13) 2
46,XN,t(2;3) 1 46,XN,t(8;19) (q24.3;q13.1) 1
46,XN,t(3;15) 1 46,XN,t(6;14) (q25;q24) 1
46,XN,t(6;7) 1 46,XN,t(2;15) (q21;q26) 1
45,XN,der(13;14)(q10;q10) 6 47,XN,+mark 1
46,XN,t(4;10)(p15.3;q26.3) 2
46,XN,t(10;16)(q22,q24) 2
45,XN,der(15;21)(q10;q10) 1
Total 114 79
karyotyping results due to the failure of amniocytes
culture, indicating the successful cytogenetic analysis
rate is 99.93% (2928/2930). The results of conventional
karyotyping are summarized in Table 1. As showed, the
karyotyping confirmed 2735 cases of euploid and 193
cases of abnormal karyotypes. Thus, the abnormal
karyotype rate is 6.59% (193/2928). Of the 193 cases of
abnormalities, 114 cases were identified as numerical
chromosomal abnormality involved in 13, 18, 21, X, and
Y, and 79 cases were classified as structural
chromosomal abnormality related with translocation,
inversion, mosaic, etc. In addition, 59.65% (68/114) of
numerical chromosomal abnormality is karyotype
47,XN,+21 and 43.04% (34/79) of structural
chromosomal abnormality is karyotype 46,XN,inv(9).
FISH analysis
All the 2930 amniotic fluid samples were successfully
detected through the FISH assay. As shown in Table 2,
FISH identified 114 cases of numerical chromosomal
abnormality and the results were well consistent with
karyotyping. In addition, 2 cases with 46,XN,der(21;22)
(q10;q10) and 46,XN,der(14;21) (q10;q10) were identified

4. Evaluation of the accuracy of FISH plus conventional fetal karyotyping in a University Hospital in China
Li et al. 014
Table 2. Comparison of FISH with karyotyping results
Indications Cases Karyotype FISH
Normal Structural aberrant Numerical aberrant Normal Aberrant
Positive maternal serum test 1530 1434 * 32 63 1467 63
Advancedmaternalage (≥35)
1032 967 * 22 42
†
989 43
‡
Ultrasound abnormality
65 55 3 7 57 8
‡
The history of ill pregnancy
207 202 3 2 205 2
Others 96 77 19 0 94 0
Total 2930 2735 79 114 2814 116
Note: *one case of the failure of amniocytes culture.
†
47,XN,inv(9),+21 is classified as numerical chromosomal abnormality.
‡
two cases of structural aberrant: 46,XN,der(21;22) (q10;q10) and 46,XN,der(14;21) (q10;q10) were identified as 47,XN,+21 by FISH.
as 47,XN,+21 by FISH assay.1 case was detected as
46,XX by FISH assay, while it was identified as
47,XX,+mar by karyotyping. Except for 2 failure cases of
amniocytes culture and 79 cases of structural
chromosomal abnormality, 2735 case of FISH results
were in agreement with the conventional cytogenetic
results. Moreover, the other 77 cases of structural
chromosomal abnormality exhibited normal FISH results
because of the probe limitations.
Correlation of prenatal indications with abnormal
karyotypes
As shown in Table 3, chromosomal aberrations were
identified in 95 (95/1530, 6.21%) positive cases from
maternal serum test, 64 cases (64/1032, 6.20%) from
advanced maternal age, and 10 cases (10/65, 15.38%)
from ultrasound abnormality. Moreover, 5 cases of
chromosomal abnormality were validated by karyotyping
in 207 cases, whose previous child with chromosomal
abnormality. In addition, 19 cases were confirmed as
karyotype abnormality in 96 other indication cases
(19/96, 19.79%), who were cases with familial member
chromosomal abnormality.
Follow-up investigation
Fetal outcome data and detailed information from the
newborn examination showed that 2735 cases with
normal karyotyping results delivered normal phenotypic
fetuses. 114 cases with numerical chromosomal
abnormalities and 6 cases of structural chromosomal
abnormalities (two 46,XN,5p-, one 46,XN,9p-, one
46,XN,der(21;22) (q10;q10), one 46,XN,der(14;21)
(q10;q10), and one 47,XN,+mark) with induced abortion,
and the villus results were consistent with the prenatal
amniocentesis results, respectively. Other 73 cases of
structural chromosomal abnormalities consulted the
hospital geneticist and they were well-informed, finally all
of them delivered normal phenotypic fetuses.
DISCUSSION
The karyotyping and its adjunct RAD method FISH has
been used in many clinical settings to diagnosis fetal
chromosomal aberrations through invasive procedures.
Here we show, amniocentesis was performed in 2930
pregnant women. Karyotyping yielded results in 2928
cases, and 114 cases of numerical chromosomal
abnormality and 79 cases of structural chromosomal
abnormality were identified. All the 2930 cases produced
informative results and 114 cases were confirmed as
numerical chromosomal abnormality from FISH.
Moreover, the aneuploidies obtained by karyotyping and
FISH are in complete accordance with no false positive or
false negative results.
Conventional karyotyping examines all 23 pairs of
chromosomes. The amniocentesis is an important and
available diagnosis for high-risk pregnancies who reject
or missed NIPT (about $400.00), especially for those
previous child with chromosomal abnormalities in our
clinical setting (Zhou et al., 2014). Moreover,
amniocentesis cost (karyotyping + FISH) (about $400.00)
is lower than α-CGH (about $660.00) detection and it is
acceptable by most of high-risk pregnancies. To
reduce/avoid the miscarriage risk of amniocentesis, the
operation is taken by certificated trained physicians under
ultrasound guidance. And till now, we as one of the
biggest women’s hospitals in China has no
amniocentesis miscarriage occurred. In addition,
aneuploidies involving chromosomes 13, 18, 21, X and Y
could be performed by FISH within 3 working days. Thus
the rapid and accurate detection of fetus chromosomal

5. Evaluation of the accuracy of FISH plus conventional fetal karyotyping in a University Hospital in China
Int. J. Gynecol. Obstet. Res. 015
Table 3. Correlation of prenatal indications with abnormal karyotype
Indications Karyotype Cases Indications Karyotype Cases Indications Karyotype Cases
Positive
maternal
serum test
47,XN,+21 43
Advanced
maternal
age (≥35)
47,XN,+21 21
Familial
chromosom
al
abnormality
46,XN,inv(9) 2
47,XN,+18 12 47,XN,+18 7 46,XN,t(2;15) (q21;q26) 1
47,XN,+13 1 47,XXY 8 45,XN,der(15;21)(q10;q10) 1
47,XXY 1 47,XYY 3 46,XN,t(7;11) (p22,p23) 2
47,XXX 2 45,X 1 46,XN,t(1:2:4) 1
45,X 3 47,XXX 1 46,XN,t(11;16) 1
45,X/46,XX 1 46,XN,inv(7)(p14;q21) 1 46,XN,t(2;3) 1
46,XN,inv(9) 19 46,XN,del(9)(p23) 1 46,XN,t(3;15) 1
46,XN,5p- 2 46,XN,inv(9) 10 46,XN,t(6;7) 1
46,XN,9p- 1 47,XN,inv(9),+21 1 46,XN,t(8;18) 1
46,XY,t(Y;21) 2 46,X,t(X;3) (p22;q29) 1 46,XN,t(4;10)(p15.3;q26.3) 2
46,XN,t(2;16)(p21,q21) 1 46,XN,der(14;21) (q10;q10) 1 46,XN, t(10;16)(q22,q24) 2
45,XN,der(13;14)(q10;q10) 1 46,XN,inv(4) 1 46,XN,t(9;14) (p12 ;q13) 2
46,XN,del(3)(p24) 1 45,XN,der(13;14) (q10;q10) 5 46,XN,t(8;19) (q24.3;q13.1) 1
46,XN,der(7)t(3;7)(q25;q32) 1 47,XN,+mark 1
Ultrasound
abnormality
47,XN,+21 2
46,XN,t(5;20) (q23;q13.3) 1 46,X,t(X;16)(p22;p12) 1 47,XN,+18 2
46,XN,t(11;15) (q23; p10) 1
The history
of ill
pregnancy
47,XN,+21 2 47,XN,+13 1
46,XN,inv(2)(p23;q23) 1 46,XN,inv(9) 1 45,X 1
46,X,inv(Y) 1 46,X,inv(Y) 1 69,XXX 1
46,XN,t(6;14) (q25;q24) 1
46,XN,inv(9) 2
46,XN,der(21;22) (q10;q10) 1

6. Evaluation of the accuracy of FISH plus conventional fetal karyotyping in a University Hospital in China
Li et al. 016
aberrations would not only alleviate patient and physician
anxiety, but also help the pregnancies make an early
reliable decision in selecting the fetus after the careful
genetic counseling.
Chromosomal inversion and translocation could be
inherited from parent. Our study exhibited that 19 cases
of chromosomal abnormality and it was inherited from
one familial parent (Table3). Therefore, parents’
chromosomal phenotypes are important for further
diagnosis of fetus structural chromosomal abnormalities
and then to enhance decision making and clinical
management of patient as well as alleviate parental
anxiety.
At present, αCGH has been adopted in clinical settings to
detect the whole genome scans instead of karyotype
analysis (Hills et al., 2010). In our hospital, after the
effective communication between patients and physicians
this powerful molecular cytogenetic tool would be
recommended to pregnancies. For example, one case in
this study showed the 47, XN,+mark karyotype and the
cordocentesis procedure was performed to conduct
αCGH, which showed the mark is idic (15). Based on
these confirmed results and subsequent genetic
counseling, induced abortion was chosen by the pregnant
woman and her family. To date, most pregnancies
choose karyotyping rather than new technologies such as
αCGH for amniocentesis confirmation, and it mainly
depends on their family income, the acceptance of new
technology, and privacy, etc.
Our hospital offered NIPT detection at a gestational age
of 12 to 24weeksas a screening tool to reduce the false
positive rate from biochemical screening tests [8], and
invasive amniocentesis diagnosis at a gestational age of
18 to 24weeks. Those with positive NIPT outcomes will
be recommended for amniocentesis diagnosis and the
cost of amniocentesis and karyotyping was covered by
the insurance (Zhou et al., 2014). All this is to diagnosis
chromosomal abnormalities and make sure safer means
of termination with fewer complications could be taken for
positive outcomes.
CONCLUSION
Invasive procedure validation through karyotyping is still
important for high-risk pregnancies in our hospital.
Karyotyping coupled with FISH can make rapid and
accurate diagnosis of fetal chromosomal aberrations,
which will help clinical decision-making thus to reduce
birth defects. Moreover, our data reflects the relationships
between genetic disorders especially the chromosomal
abnormalities with possible birth defects, it provides
scientific basis for disease intervention, health resource
distribution, social welfare, rehabilitation and scientific
research in Zhejiang Province, China.
Conflict of Interest
The authors declare that they have no conflict of interest.
ACKNOWLEDGEMENTS
This work is supported by National Natural Science
Foundation of China (No. 81170620), Research Project
of Chinese Ministry of Education (No.113038A), Science
and Technology Project of Zhejiang Province (No.
2010C33096). The authors acknowledged the
contributions of the anonymous reviewers which helped
to improve the quality of this paper.
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Accepted 25 July, 2015.
Citation: Li H, Zhou Q, Chen S, Luo Y, Pan L, Qian Y,
Xu C (2015). Amniotic fluid amino acid concentrations in
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Copyright: © 2015 Li et al. This is an open-access article
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Attribution License, which permits unrestricted use,
distribution, and reproduction in any medium, provided
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