Chromosome Abnormalities Detected at Prenatal Diagnosis

Author(s):  
R. J McKinlay Gardner ◽  
David J Amor

Prenatal diagnosis has given medical cytogenetics one of its major areas of application: from amniocentesis in the earliest days to the recent developments of noninvasive prenatal testing based upon a sample of maternal blood. This chapter explores in detail the specific diagnoses that may be made and the decisions, with particular reference to continuation or termination of pregnancy, that face those women/couples for whom a specific diagnosis has been made. The difficulties of decision inherent in a sex chromosome aneuploidy, a microarray-level rearrangement, and in the context of mosaicism are rehearsed. This discussion is offered on the background of a review of the applied embryology.

Author(s):  
Yunfang Shi ◽  
Xiaozhou Li ◽  
Duan Ju ◽  
Yan Li ◽  
Xiuling Zhang ◽  
...  

<b><i>Objective:</i></b> This study was designed to investigate the efficiency of noninvasive prenatal testing (NIPT) for screening fetal sex chromosome aneuploidies (SCAs) through sequencing of cell-free DNA in maternal plasma. <b><i>Methods:</i></b> This is a retrospective study on the positive NIPT results for SCAs collected from our hospital between January 2012 and December 2018. Samples with positive NIPT results for SCAs were then confirmed by prenatal or postnatal karyotyping analysis. <b><i>Results:</i></b> After cytogenetic analysis, abnormal karyotypes were confirmed in 104 cases and the overall positive predictive value (PPV) of NIPT for SCAs was 43.40% (102/235). The most frequently detected karyotypes included 47,XXY (<i>n</i> = 42), 47,XXX (<i>n</i> = 20), 47,XYY (<i>n</i> = 16), and 45,X (<i>n</i> = 2). Meanwhile, 10 cases were confirmed with mosaic karyotype 45,X/46,XX and 14 cases with numerical or structural chromosome abnormalities, including a double trisomy 48,XXX,+18. Cytogenetic results from the other 131 cases showed normal XX or XY, which were discordant with NIPT results. Upon analysis of parental karyotypes, 29 (12.34%) showed false positivity in NIPT results that were caused by maternal sex chromosome abnormalities. <b><i>Conclusion:</i></b> NIPT is an effective screening tool for SCA with a PPV of 43.40%. Maternal karyotype abnormalities occurred in 12.34% of the cases with abnormal NIPT. Diagnostic testing of the fetus and the mother are recommended.


2015 ◽  
Vol 125 (2) ◽  
pp. 390-392 ◽  
Author(s):  
Christopher J. McNamara ◽  
Laura A. Limone ◽  
Thomas Westover ◽  
Richard C. Miller

2017 ◽  
Vol 37 (5) ◽  
pp. 515-520 ◽  
Author(s):  
Rosemary E. Reiss ◽  
Marie Discenza ◽  
Judith Foster ◽  
Lori Dobson ◽  
Louise Wilkins-Haug

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Xinran Lu ◽  
Chaohong Wang ◽  
Yuxiu Sun ◽  
Junxiang Tang ◽  
Keting Tong ◽  
...  

Abstract Objective To assess the positive predictive value (PPV) of noninvasive prenatal testing (NIPT) as a screening test for sex chromosome aneuploidy (SCA) with different maternal characteristics and prenatal decisions in positive cases. Materials and methods We retrospectively analysed 45,773 singleton pregnancies with different characteristics that were subjected to NIPT in the Maternity and Child Health Hospital of Anhui Province. The results were validated by karyotyping. Clinical data, diagnostic results, and data on pregnancy outcomes were collected. Results In total, 314 cases were SCA positive by NIPT; among those, 143 underwent invasive prenatal diagnostic testing, and 58 were true-positive. Overall, the PPVs for 45,X, 47,XXX, 47,XXY and 47,XYY were 12.5%, 51.72%, 66.67% and 83.33%, respectively. Interestingly, when only pregnant women of advanced maternal age (AMA) were screened, the PPVs for 45,X, 47,XXX, 47,XXY and 47,XYY were 23.81%, 53.33%, 78.95%, and 66.67%, respectively. The frequency of SCA was significantly higher in the AMA group than in the non-AMA group. The frequencies of 47,XXX and 47,XXY were significantly correlated with maternal age. Conclusion NIPT performed better in predicting sex chromosome trisomies than monosomy X, and patients with 45,X positive foetuses were more eager to terminate pregnancy than those with 47,XXX and 47,XYY. AMA may be a risk factor of having a foetus with SCA. Our findings may assist in genetic counselling of AMA pregnant women. Our pre- and posttest counselling are essential for familiarizing pregnant women with the benefits and limitations of NIPT, which may ease their anxiety and enable them to make informed choices for further diagnosis and pregnancy decisions.


2020 ◽  
Author(s):  
Xiaojin Luo ◽  
Liang Hu ◽  
Yuanyuan Pei ◽  
Xiaoyi Cong ◽  
Xiaoyi Liu ◽  
...  

Abstract Objective To estimate the positive predictive value (PPV) of fetal sex chromosome aneuploidy (SCA) screened in non-selective population and explore the rate of pregnancy termination and ultrasound findings for fetal SCA and the factors influencing parents’ decisions in South China. Methods This is a large-scale retrospective cohort of positive SCA screened from unselected singleton pregnancies by non-invasive prenatal testing (NIPT) from a single prenatal center of a tertiary hospital, from January 2016 to November 2019. Clinical information, indications, diagnostic results, ultrasound findings, pregnancy determinations, and follow-up were reviewed and analyzed. Results 248 cases of SCA positive were screened out of 52453, giving a positive detection rate of 0.47%. The majority of indications (42.7%) were low-risk pregnancies. After genetic counseling, 43 pregnancies (17.3%) declined to prenatal diagnosis, the rest of 205 cases (82.7%) conducted with amniocentesis to detect fetal chromosome, of which 95 were confirmed as true positive of SCA with PPV of 46.3% (95/205). The SCA consisted of 68 sex chromosomal trisomies (26 cases of 47,XXY, 20 cases of 47,XXX and 22 cases of 47,XYY), 17 cases of monosomy X (45,X), three cases of 48,XXYY, three cases of mosaicisms (45,X/46,XX), four cases with sex chromosomal deletions, included two cases of 46,X,del(Y)(q11.21), one case of 46,X,del(X)(p11) and one case of 46,X,i(X)(q10). Of the 95 cases confirmed as true positive SCA, 50 cases (52.6%)chose to terminate the pregnancy (82.6%, 64.3%, 17.6% and 33.3% for 45,X, 47,XXY, 47,XXX and 47,XYY, respectively), 45 cases (47.4%) elected to continue the pregnancy. Ninety-three pregnant were also continued pregnancy after the exclusion of SCA. Conclusions NIPT, as a first-tier routine method for screening autosomal aneuploidies, also could play an important role in screening SCA. Low-risk pregnant women are the main indication for the detection of SCA as NIPT test provides to non-selective population. The trend of overall termination rates of SCA-affected pregnancies is decreased. For 47,XXX and 47,XYY with mild phenotype, couples would like to continue the pregnancy. But for 45,X and 47,XXY, parents apt to terminate pregnancy no matter ultrasound abnormalities were found or not. pregnancy determinations are affected by types of SCA, sonographic findings, maternal age, and presence of infertility.


2020 ◽  
Author(s):  
Xiaojin Luo ◽  
Liang Hu ◽  
Yuanyuan Pei ◽  
Xiaoyi Cong ◽  
Xiaoyi Liu ◽  
...  

Abstract Objective To estimate the positive predictive value (PPV) of fetal sex chromosome aneuploidy (SCA) screened in non-selective population and explore the rate of pregnancy termination and ultrasound findings for fetal SCA and the factors influencing parents’ decisions in South China.Methods This is a large-scale retrospective cohort of positive SCA screened from unselected singleton pregnancies by non-invasive prenatal testing (NIPT) from a single prenatal center of a tertiary hospital, from January 2016 to November 2019. Clinical information, indications, diagnostic results, ultrasound findings, pregnancy determinations, and follow-up were reviewed and analyzed.Results 248 cases of SCA positive were screened out of 52453, giving a positive detection rate of 0.47%. The majority of indications (42.7%) were low-risk pregnancies. After genetic counseling, 43 pregnancies (17.3%) declined to prenatal diagnosis, the rest of 205 cases (82.7%) conducted with amniocentesis to detect fetal chromosome, of which 95 were confirmed as true positive of SCA with PPV of 46.3% (95/205). The SCA consisted of 68 sex chromosomal trisomies (26 cases of 47,XXY, 20 cases of 47,XXX and 22 cases of 47,XYY), 17 cases of monosomy X (45,X), three cases of 48,XXYY, three cases of mosaicisms (45,X/46,XX), four cases with sex chromosomal deletions, included two cases of 46,X,del(Y)(q11.21), one case of 46,X,del(X)(p11) and one case of 46,X,i(X)(q10). Of the 95 cases confirmed as true positive SCA, 50 cases (52.6%)chose to terminate the pregnancy (82.6%, 64.3%, 17.6% and 33.3% for 45,X, 47,XXY, 47,XXX and 47,XYY, respectively), 45 cases (47.4%) elected to continue the pregnancy. Ninety-three pregnant were also continued pregnancy after the exclusion of SCA.Conclusions NIPT, as a first-tier routine method for screening autosomal aneuploidies, also could play an important role in screening SCA. Low-risk pregnant women are the main indication for the detection of SCA as NIPT test provides to non-selective population. The trend of overall termination rates of SCA-affected pregnancies is decreased. For 47,XXX and 47,XYY with mild phenotype, couples would like to continue the pregnancy. But for 45,X and 47,XXY, parents apt to terminate pregnancy no matter ultrasound abnormalities were found or not. pregnancy determinations are affected by types of SCA, sonographic findings, maternal age, and presence of infertility.


2015 ◽  
Vol 125 ◽  
pp. 92S ◽  
Author(s):  
Ruth Morgan Farrell ◽  
Patricia Agatisa ◽  
Angela Leek ◽  
Mary Beth Mercer ◽  
Marissa Smith ◽  
...  

2020 ◽  
Author(s):  
Xinran Lu ◽  
Chaohong Wang ◽  
Yuxiu Sun ◽  
Junxiang Tang ◽  
Keting Tong ◽  
...  

Abstract Objective: To investigate the positive predictive value (PPV) and clinical features of non-invasive prenatal testing (NIPT) as a screening method in detecting sex chromosome aneuploidy (SCA) within a high-risk population at the Maternity and Child Health Hospital of Anhui Province.Methods: From June 2015 to June 2019, 45773 women with singleton pregnancies volunteered to take an NIPT. Cell-free fetal DNA was extracted for high-throughput sequencing and amniocentesis karyotype analysis was performed in pregnant women. Results: 314 high-risk pregnant women underwent NIPT and 143 chose invasive prenatal diagnosis. Karyotype analysis was performed in amniotic fluid cells, wherein 7 cases of 45,X (PPV: 12.50%), 16 cases of 47,XXX (PPV: 55.17%), 25 cases of 47,XXY (PPV: 71.43%), and 10 cases of 47,XYY(PPV: 76.92%) were confirmed. The PPV of NIPT for SCA was 40.56%. The rate of SCA detected in women aged 40 years and older was 0.39%, which was significantly different from that detected in women aged <30, 30–34, and 35–39 years (P < 0.05). The detection rates of 47,XXX and 47,XXY were significantly correlated with maternal age (P < 0.05), but those of 45,X and 47,XYY showed no significant correlation with maternal age.Conclusion: NIPT can be applied for the detection of SCA, but the detection accuracy is low. Genetic counseling and further prenatal diagnosis should be provided.


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