Changing indications for invasive testing in an era of improved screening

Determinant of Prenatal Diagnostic Testing among Women with Increased Risk of Fetal Aneuploidy and Genetic Disorders

OBJECTIVE

 This study aimed to assess factors that influence patients' decisions in accepting prenatal diagnostic testing following genetic counseling for increased risk of fetal aneuploidy.

METHODS

 This is a retrospective cohort study of women at increased risk of fetal aneuploidy and genetic disorders who had genetic counseling from January 2012 to December 2016 at a single academic center. Demographics, indications for genetic counseling, and rates of diagnostic testing were collected and compared between those who accepted diagnostic testing and those who chose cell free DNA. The variables were analyzed using Chi-square, Fisher's exact test, and multiple logistic regression.

RESULT

 Of the 2,373 pregnant women who underwent genetic counseling for increased risk of fetal aneuploidy and genetic disorders during the study period, 321 women had diagnostic testing (13.5%). Women at 35 years and older accepted diagnostic testing more than women younger than 35 years (20.7 vs. 11.5%, p < 0.001). Asian women accepted diagnostic testing at 27.7% more than white, non-Hispanic Black, and Hispanic women at 18.0, 12.1, and 11.7%, respectively, p = 0.002. Number of indications for genetic counseling influenced the likelihood of accepting diagnostic testing. Women with one indication had 11.5% acceptance of diagnostic testing, and with two and three indications, it was 17.0 and 29.2%, respectively. The commonest indication for diagnostic testing was cystic hygroma (risk ratio [RR] = 7.5, 95% confidence interval [CI]: 3.12-8.76 p < 0.001). The relative risk of diagnostic testing for fetuses with shortened long bones, femur and humerus, thickened nuchal fold, echogenic bowel, single umbilical artery, and increased nuchal translucency were 4.0, 3.3, 3.1, 2.7, and 2.7, respectively. Abnormal serum analyte alone was associated with less acceptance of diagnostic testing (RR = 0.8, 95% CI: 0.7-0.96, p = 0.017).

CONCLUSION

 Age, race, ethnicity, and cumulative number of indications for genetic counseling influenced acceptance of diagnostic testing in at-risk women of fetal aneuploidy and genetic disorders.

KEY POINTS

· Genetic counseling.. · Fetal aneuploidy.. · Genetic disorders.. · Prenatal diagnostic testing. Prenatal diagnostic testing in women with increased risk of fetal aneuploidy and genetic disorders..

The Effect of Resolution Level and Targeted Design in the Diagnostic Performance of Prenatal Chromosomal Microarray Analysis

INTRODUCTION

This study was performed to assess the optimal resolution for prenatal testing by array comparative genomic hybridization (aCGH), aiming to balance between maximum diagnostic yield and minimal detection of variants of uncertain significance (VOUS).

METHODS

This was a prospective study using data of 2,336 fetuses that underwent invasive prenatal diagnosis, and the samples were analyzed by aCGH. In total, six different aCGH platforms were studied; four different resolutions (0.18 Mb, 0.5 Mb, 1 Mb, and 2 Mb) and two platform designs (whole-genome [WG] and targeted). The results of these designs were compared based on their diagnostic yield and VOUS rate. The performance of the different designs was further analyzed according to indication for invasive testing.

RESULTS

The diagnostic yield of copy number variants increased with increasing level of analysis. The detection rates of clinically significant chromosomal abnormalities were almost the same across our targeted array designs; 7.2% with 0.18 Mb backbone/0.05 Mb versus 7.1% with 0.5 Mb backbone/0.05 Mb (p >0.05). However, a significant difference in the rate of VOUS was observed; 9.4% with 0.18 Mb backbone/0.05 Mb versus 6% with 0.5 Mb backbone/0.05 Mb (p <0.001). After analyzing the results across different indications for testing, we found that the application of non-targeted platform designs and lower levels of resolution analysis (such as 1 Mb WG or 0.5 MbL/1 MbG WG) would offer similar diagnostic yield in most cases with major congenital anomalies, with lower VOUS rates. However, the sample size for many indication groups was too small to extract robust associations.

CONCLUSION

It appears that the targeted array platform with 0.5 Mb backbone resolution and 0.05 Mb on targeted gene-rich regions is optimal for routine chromosomal microarray analysis use in prenatal diagnosis. It may be beneficial to individualize the minimum resolution in specific referral indications as the indications for invasive prenatal testing may be quite heterogeneous.

Never "totally prepared": Support groups on helping families prepare for a child with a genetic condition

A rapid increase in the reach and breadth of prenatal genetic screening and testing has led to an expanding need for prenatal support of families receiving this genetic information. As part of a larger study investigating prenatal preparation for a child with a genetic condition, we interviewed representatives of patient advocacy groups (PAGs) who support parents post-diagnosis. Groups supporting families with Down syndrome were often local or regional, while other groups were often national or international in scope. Groups varied in their willingness or ability to support families prior to making a pregnancy continuation decision, and participants reflected on ways they addressed these needs with individual counseling and referrals, if needed. Participants described supporting parents with information about conditions and a range of lived experiences for families, while referring families to healthcare professionals for technical questions and additional medical needs. PAGs also prioritized connecting parents experiencing a new diagnosis with other families for peer support and community-building, both in person and on social media. Participants discussed limitations, such as a lack of racially-concordant support, ability to offer resources in languages other than English, and a lack of funding to meet the expressed needs of families post-diagnosis. Overall, participants emphasized that the parenting experience of each child is unique, irrespective of a genetic diagnosis, an experience for which parents can never be "totally prepared."

Access to Prenatal Testing and Ethically Informed Counselling in Germany, Poland and Russia

The development of new methods in the field of prenatal testing leads to an expansion of information that needs to be provided to expectant mothers. The aim of this research is to explore opinions and attitudes of gynecologists in Germany, Poland and Russia towards access to prenatal testing and diagnostics in these countries. Semi-structured interviews were conducted with n = 18 gynecologists in Germany, Poland and Russia. The interviews were analyzed using the methods of content analysis and thematic analysis. Visible in all three countries is a connection of prenatal medicine with the politically and socially contentious issue of pregnancy termination. Respondents in Poland and Russia concentrated on the topic of inadequate resources. Quality of information for expectant mothers is an important point in all three countries. Only in Germany was the issue of language barriers in communication raised. With regard to non-invasive prenatal testing (NIPT) respondents in Germany focused on the ethical issues of routinization of testing; in Poland and Russia they concentrated on fair access to NIPT. Challenges in all three countries arise from structural factors such as imprecise and prohibitive regulations, lack of resources or organization of healthcare services. These should be addressed on a political and medico-ethical level.

Utility of noninvasive genome-wide screening: a prospective cohort of obstetric patients undergoing diagnostic testing

PURPOSE

Copy-number variant (CNV) assessment is recommended for patients undergoing prenatal diagnostic testing. Noninvasive screening tests have not been extensively validated for CNV detection. The objective of this study was to compare the ability of genome-wide noninvasive prenatal screening (NIPS) to chromosomal microarray to detect clinically significant findings.

METHODS

We prospectively enrolled 198 subjects at the time of consent for diagnostic prenatal testing. Genome-wide NIPS results were compared with diagnostic testing results to assess NIPS test performance (n = 160, 38 subjects without microarray results excluded). Cohen's kappa statistic was used to assess test agreement.

RESULTS

Genome-wide NIPS did not detect clinically significant chromosomal abnormalities at the same rate as diagnostic testing, κ = 0.75 (95% confidence interval [CI], 0.62-0.87). When excluding CNVs <7 Mb and findings outside the limits of genome-wide NIPS, test agreement improved, κ = 0.88 (0.79-0.97) driven by agreement for common aneuploidies (κ = 1.0). However, among patients with an abnormal fetal survey, agreement was only fair, κ = 0.38 (0.08-0.67).

CONCLUSION

While NIPS is an excellent screening test for common aneuploidies, genome-wide NIPS misses clinically significant findings detected on routine diagnostic testing. False positive and false negative cases highlight the importance of pretest counseling regarding NIPS limitations, especially in the setting of fetal anomalies.

Non-invasive prenatal testing in the context of IVF and PGT-A

The high incidence of chromosome aneuploidy in human gametes and embryos is a major cause of in vitro fertilization (IVF) failure and miscarriage. In order to improve live birth rates with single embryo transfer, the use of preimplantation genetic testing for aneuploidy (PGT-A) has significantly increased. PGT encompasses methods that allow embryos to be tested for inherited conditions or screened for chromosomal abnormalities. However, PGT-A is a screening method and results can never be used to definitively predict the chromosomal status of the embryo and fetus. The objective of this manuscript is to review prenatal screening and diagnostic methods available in pregnancies conceived by IVF-PGT-A.

In-house genetic counseling increases the detection of abnormal karyotypes-a 26-year experience in prenatal diagnosis in a single tertiary referral hospital in Poland

Purpose

To evaluate the trends in prenatal diagnosis over 26 years in a tertiary referral hospital.

Methods

A retrospective analysis of invasive prenatal procedures performed between 1991 and 2016. Maternal characteristics, indications for invasive diagnosis, and percentage of abnormal karyotypes were compared between periods according to guidelines implemented nationally and locally.

Results

A total of 14,302 invasive prenatal procedures were performed. The proportion of invasive procedures performed for advanced maternal age, abnormal karyotype in a previous pregnancy, and maternal anxiety decreased from 71.1%, 17.8%, 8.9% in 1991 to 23.9%, 1.3%, and 2.3% in 2016 (OR 0.6, 0.8, and 0.9 for each 5 years, respectively; p < 0.001), while the proportion of invasive procedures performed for abnormal ultrasound increased from 2.2% in 1991 to 51.6% in 2016 (OR 1.9 for each 5 years; p < 0.001). Abnormal karyotype was found in 9.7%. The proportion of abnormal karyotypes increased significantly from 0.0% in 1991 to 15.7% in 2016 (OR 1.35 for each 5-year period; p < 0.001). The odds of abnormal karyotype increased after the implementation of the Ordinance of the Minister of Health in 2003 (OR 1.6), the National Prenatal Screening Program in 2007 (OR 2.2), and the in-house genetic counseling with combined first trimester screening in 2015 (OR 3.1).

Conclusions

Significant changes in prenatal diagnosis led to a better selection of patients undergoing invasive prenatal procedures. The implementation of in-house genetic counseling was associated with an increased rate of the detection of abnormal karyotypes.

The impact of preimplantation genetic testing on prenatal diagnostic procedures

OBJECTIVE

In recent years, cell-free DNA screening has significantly reduced the number of invasive prenatal diagnostic testing in pregnancy. Preimplantation genetic testing for aneuploidies (PGT-A) is a commonly performed screening test in in vitro fertilization (IVF) pregnancies. Therefore, we aimed to determine the impact of PGT-A on subsequent utilization of prenatal diagnostic testing in IVF pregnancies.

METHODS

Retrospective cohort of singleton and twin IVF pregnancies at a single center from January 2014 to December 2017. The rate of invasive diagnostic genetic testing (chorionic villus sampling (CVS) and/or amniocentesis) was compared between patients with pregnancies achieved after transfer of a euploid embryo by PGT-A (n = 71) and those with pregnancies achieved after transfer of an untested embryo (n = 38). Wilcoxon rank sum and Fisher's exact tests were used for statistical analysis.

RESULTS

There was no statistically significant difference in the number of prenatal diagnostic procedures (25.4% PGT-A euploid embryo versus 31.6% untested embryo, p = .51 and p = .32 for one-sided and two-sided analyses, respectively) between the two groups. Maternal age, nuchal translucency measurements and the rate of abnormal sonographic findings were similar between the two groups. Patients without PGT-A pregnancies had a higher BMI (mean 29.6, p = .01) and were ethnically different (p = .013) compared to those with PGT-A.

CONCLUSION

The implementation of PGT-A in IVF patients did not reduce the number of invasive diagnostic tests performed at our institution.

Single Nucleotide Polymorphism-Based Noninvasive Prenatal Testing: Experience in India

INTRODUCTION

Noninvasive prenatal testing (NIPT) has revolutionized prenatal screening for chromosomal aneuploidies in some countries. Its implementation has been sporadic in developing countries. Given the genetic variation of the people in different countries, we evaluated the performance of the SNP-based NIPT in India .

MATERIALS AND METHODS

The Panorama™ NIPT was performed in 516 pregnancies, which had tested intermediate-to-high risk on conventional first and second trimester screening. Results were confirmed either by invasive diagnostic testing or by clinical evaluation after birth.

RESULTS

Of 511 samples analyzed, results were obtained in 499 (97.7%). Of these, 480 (98.2%) were low risk and 19 were high risk. A sensitivity of 100% was obtained for detection of trisomies 21, 18, 13 and sex chromosomal abnormalities. The specificity ranged from 99.3 to 100% for abnormalities tested. Taken together, the positive predictive value for trisomies 21, 18, 13 and monosomy X was 85.7%. The average fetal fraction was 8.2%, which is lower than the average observed elsewhere.

CONCLUSION

This is the first report of detailed experience with NIPT in India and demonstrates comparable performance in all aspects of testing to the results elsewhere.

New Frontiers in Our Understanding of Lymphatic Malformations of the Head and Neck: Natural History and Basic Research

The future of head and neck lymphatic malformation (HNLM) evaluation and treatment is changing because of 2 decades of clinical research and recent basic science investigation. Basic science investigation using cellular biology and molecular genetics has revealed the genetic cause of some HNLMs, which has created the possibility of medical treatment specific to HNLM. This article summarizes the clinical and basic science research that will likely influence the future of HNLM assessment and treatment.

Genetic testing and autism: Tutorial for communication sciences and disorders

This tutorial provides professionals in communication sciences and disorders with an overview of the molecular basis and parental perceptions of genetic testing as associated with autism. The introduction notes the prominence of genetic testing within present-day medical practices and highlights related limitations and concerns through the lens of disability critique. The body of the tutorial provides an overview of four different forms of genetic variation, highlighting the potential associations with autism and available genetic testing. In sum, most autism cases cannot be associated directly with specified forms of genetic variation but are attributed instead to multiple genetic and environmental influences working in concert. Finally, the discussion focuses on parental perceptions of the genetic testing associated with autism, both the potential benefits and harms, and emphasizes the need to integrate first-person perspectives from autistic individuals.

Summary of 2185 prenatal invasive procedures in a single center: A retrospective analysis

Objective:

To determine the frequency, indications, and outcomes of diagnostic invasive prenatal procedures (DIPP) performed in a university hospital.

Materials and Methods:

This retrospective, observational study included 2185 cases of DIPP (chorionic villus sampling, amniocentesis, and cordocentesis) performed at the department of obstetrics and gynecology of a university hospital between 2010 and 2016. We included all DIPP cases performed between 11 and 24 weeks of gestation. We compared the different types of DIPP performed in our hospital.

Results:

Two thousand one hundred eighty-five procedures were performed (1853 amniocenteses, 326 chorionic villus sampling, and 6 cordocenteses). The main indication for performing invasive procedures was abnormal results of aneuploidy screening for trisomy 21, followed by maternal age, and fetal structural abnormality. The fetal karyotype was altered in 154 (26.1%) cases. Trisomy 21 was the most common aneuploidy followed by trisomy 18, monosomy X, and trisomy 13. Fetal karyotype could not be revealed in 42 (2%) cases due to maternal contamination in 18 cases, inadequate sampling in 4 cases, and failure of cell culture in 27 cases. There were 2 pregnancy losses due to the invasive procedure (only in amniocentesis).

Conclusion:

The ideal approach to pregnancies with a detected chromosomal abnormality should be tailored according to the individual choice of the couples regarding whether they decide for or against a child with a known chromosomal abnormality.

Revisiting the challenges of training Maternal Fetal Medicine fellows in chorionic villus sampling

BACKGROUND

More than a decade ago, researchers described a survey of Maternal Fetal Medicine fellows that showed that chorionic villus sampling training was limited for Maternal Fetal Medicine fellows in the United States. Prenatal screening and diagnosis have rapidly evolved since then and include the introduction of noninvasive aneuploidy screening that uses cell-free fetal DNA. Yet, chorionic villus sampling remains the only method available for first-trimester genetic diagnosis.

OBJECTIVE

This study evaluated the chorionic villus sampling training of Maternal Fetal Medicine fellows with respect to availability, competency standards, and education methods.

STUDY DESIGN

In November 2015, an electronic survey was sent to Maternal Fetal Medicine fellows and fellowship directors of accredited Maternal Fetal Medicine fellowship programs in the United States.

RESULTS

Fifty-eight percent of fellows (179/310) and 46% of program directors (35/76) responded. Ninety-five percent of Maternal Fetal Medicine fellows think that invasive diagnostic testing is essential to their training; 100% of fellows have amniocentesis training; and 65% have chorionic villus sampling training. The median number of chorionic villus sampling procedures that are expected during a fellowship in those who trained was 10. Eighty-eight percent of fellows and 89% of program directors state that chorionic villus sampling training could be better; 89% of fellows and 97% of directors would like access to simulated models. Barriers to training included lack of patients (71%) and lack of proficient attending supervisors (43%).

CONCLUSION

Since the last survey, >10 years ago, chorionic villus sampling training has declined further. A decrease in the number of procedures that are performed is the leading barrier to this training.

Prenatal diagnosis of congenital upper limb differences: a current concept review

Congenital upper limb differences are frequently associated with complex syndromes. Ultrasonography is considered as the first-line diagnostic modality, and fetal MRI can be useful to further evaluate ill-defined areas. Genetic and non-invasive prenatal testing help to identify the underlying genetic disorder. The diagnostic assessment is a multidisciplinary task that should involve early prenatal consultations with specialists involved in case management and treatment planning. Obstetricians, geneticists, radiologists, psychologists and dedicated surgeons are needed to provide good parental education, prenatal and postnatal care, and successful outcomes. The purpose of this review is to provide an overview of the clinicopathologic background, current diagnostic and imaging procedures in affected fetuses.