Practice Bulletin No. 162

Social vulnerability and prenatal diagnosis

OBJECTIVES

There are limited data on how neighborhood-level risk factors affect the likelihood of having prenatal diagnosis. Neighborhood social vulnerability can be quantified and ranked using the social vulnerability index (SVI), a tool that measures the cumulative effect of external stressors in the local environment that may affect health outcomes. The objective of the study was to determine the relationship between SVI and prenatal diagnosis among pregnant patients who received genetic counseling.

METHODS

Retrospective cohort study of all pregnant patients who had genetic counseling at two hospitals in New York between January 2019 and December 2022. For each patient, the address of residence was linked to an SVI score (primary exposure) based on census tract. SVI scores were subdivided into fifths and analyzed categorically. The primary outcome was prenatal diagnosis (yes/no). Multivariable logistic regression was performed.

RESULTS

A total of 5,935 patients were included for analysis and 231 (3.9 %) had prenatal diagnosis. On regression analysis, no association between SVI and prenatal diagnosis was observed. Patients who had a diagnostic procedure were more likely to be English speaking (aOR 1.80; 95 % CI 1.13-2.87), carriers of a genetic disorder (aOR 1.94; 95 % CI 1.32-2.86), had increased NT (aOR 6.89; 95 % CI 3.65-13.00), abnormal NIPS (aOR 9.58; 95 % CI 5.81-15.80), or had fetal structural anomalies (aOR 10.60; 95 % CI 6.62-16.96). No differences were seen based on race and ethnicity group, insurance type, or marital status.

CONCLUSIONS

SVI score does not affect rate of prenatal diagnosis. Findings may differ in other geographic regions and populations.

Application of Whole-Exome Sequencing in the Prenatal Diagnosis of Foetuses With Central Nervous System Abnormalities

OBJECTIVE

To investigate the clinical value of whole-exome sequencing (WES) in the diagnosis of foetuses with central nervous system (CNS) abnormalities but having a normal karyotyping and chromosomal microarray result.

METHOD

During the period of 2016-2022, there were a total of 149 foetuses with CNS abnormalities but having negative karyotyping and chromosomal microarray analysis results; WES was performed on these foetuses and their parents. Variants were classified according to ACMG guidelines, and the association of pathogenic variants with specific types of CNS abnormalities was explored.

RESULTS

Among these 149 foetuses, three categories of abnormalities, namely, single CNS abnormality, multiple CNS abnormalities, CNS abnormalities along with other organ system abnormalities were identified, for which the detection rate of P/LP variants is 17.4% (12/69), 28.6% (14/49) and 54.8% (17/31), respectively.

CONCLUSION

WES brought about an increase of 28.9% in diagnostic yield in the prenatal evaluation of foetuses with CNS abnormalities but having negative karyotyping and chromosome array results. WES may also be of benefit for the diagnosis of foetuses with isolated CNS abnormalities, as well as for making more informed interpretations of imaging findings and for providing better genetic counselling.

Impact of prenatal genomics on clinical genetics practice

Genetic testing for prenatal diagnosis in the pre-genomic era primarily focused on detecting common fetal aneuploidies, using methods that combine maternal factors and imaging findings. The genomic era, ushered in by the emergence of new technologies like chromosomal microarray analysis and next-generation sequencing, has transformed prenatal diagnosis. These new tools enable screening and testing for a broad spectrum of genetic conditions, from chromosomal to monogenic disorders, and significantly enhance diagnostic precision and efficacy. This chapter reviews the transition from traditional karyotyping to comprehensive sequencing-based genomic analyses. We discuss both the clinical utility and the challenges of integrating prenatal exome and genome sequencing into prenatal care and underscore the need for ethical frameworks, improved prenatal phenotypic characterization, and global collaboration to further advance the field.

Epidermal nevi and epidermolytic hyperkeratosis: A review of cases, highlighting indications for biopsy and genetics referral

Epidermal nevi are common benign cutaneous hamartomas that may rarely demonstrate histopathologic evidence of epidermolytic hyperkeratosis (EHK), representing cutaneous mosaicism for pathogenic keratin variants. Rarely, individuals with linear epidermal nevi transmit to their children the inherited form of EHK, also known as epidermolytic ichthyosis, characterized by generalized erythema, blistering, and scaling at birth evolving to widespread hyperkeratosis. We present an updated review of reported cases of linear epidermal nevi with EHK exhibiting transmission of epidermolytic ichthyosis to guide important considerations in the care of individuals with epidermal nevi. Clinical characteristics of linear epidermal nevi do not reliably predict the presence of EHK. All reported cases of transmission to offspring have occurred in individuals with linear epidermal nevi involving more than one anatomic area suggesting increased reproductive risk with involvement of two or more anatomic sites. Therefore, genetics consultation is recommended for these individuals with biopsy-confirmed EHK. For individuals with smaller areas of epidermal nevus involvement, the implications are less well known, though genetics consultation may still be considered for those interested in further discussion of general reproductive risk.

Chromosomal microarray testing yield in 829 cases of microcephaly: a clinical characteristics-based analysis for prenatal and postnatal cases

INTRODUCTION

Microcephaly, characterized by abnormal head growth, can often serve as an initial indicator of congenital, genetic, or acquired disorders. In this study, we sought to evaluate the effectiveness of chromosomal microarray (CMA) testing in detecting abnormalities in both prenatal and postnatal cases of microcephaly.

MATERIALS AND METHODS

CMA Testing: We conducted CMA testing on 87 prenatally-detected microcephaly cases and 742 postnatal cases at a single laboratory. We evaluated the CMA yield in relation to specific clinical characteristics.

RESULTS

In prenatal cases, pathogenic and likely pathogenic (LP) results were identified in 4.6% of cases, a significantly higher rate compared to low-risk pregnancies. The male-to-female ratio in this cohort was 3, and the CMA yield was not influenced by gender or other clinical parameters. For postnatal cases, the CMA yield was 15.0%, with a significantly higher detection rate associated with dysmorphism, hypotonia, epilepsy, congenital heart malformations (CHM), learning disabilities (LD), and a history of Fetal growth restriction (FGR). No specific recurrent copy number variations (CNVs) were observed, and the rate of variants of unknown significance was 3.9%.

CONCLUSIONS

The yield of CMA testing in prenatal microcephaly is lower than in postnatal cases (4.6% vs. 15%). The presence of microcephaly, combined with dysmorphism, hypotonia, epilepsy, CHD, LD, and FGR, significantly increases the likelihood of an abnormal CMA result.

Noninvasive twin genotyping for recessive monogenic disorders by relative haplotype dosage

OBJECTIVE

To establish a haplotype-based noninvasive prenatal testing (NIPT) workflow for single-gene recessive disorders that adapt to dizygotic (DZ) twin pregnancies.

METHOD

Twin pregnancies at risk of Duchenne muscular dystrophy, Becker muscular dystrophy, hemophilia B, spinal muscular atrophy, phenylketonuria, and nonsyndromic hearing loss were recruited. For subsequent analysis, capture sequencing targeting highly heterozygotic single nucleotide polymorphism sites was conducted. Paternal-specific alleles were used to calculate the total and individual fetal fractions and determine zygosity. A two-step Bayes Factor model was applied to clarify the complex genomic landscape in the maternal plasma: the first step involved determining whether the twins inherited the same haplotype, and the second step involved estimating their individual genotypes. NIPT results were subsequently confirmed by invasive diagnosis.

RESULTS

Nine twin pregnancies were recruited, including five DZ and four monozygotic (MZ) twins. The earliest gestational age was 8+0 weeks, and the minimum fetal fraction was 4.6%. Three twin pregnancies were reported with one affected fetus, while the remaining six were reported without affected fetuses. Two dichorionic diamniotic twin pregnancies were confirmed to be MZ twins. The NIPT results were 100% consistent with those of invasive procedures or diagnostic genetic testing after birth.

CONCLUSION

This study is the first to perform NIPT for single-gene disorders in twin pregnancies and preliminarily confirm its clinical feasibility. Acknowledging the twins' genotypes in the first trimester is valuable as it empowers obstetric care providers and parents to have adequate time for pregnancy management and decision-making.

Clinical Applications of Fetal Cell-Free DNA: State of the Science

Advances in technology have correlated with expanding prenatal genetic testing options for pregnant people. Leading medical organizations recommend cell-free DNA as the most sensitive screening test for trisomies 13, 18, and 21, as well as for fetal sex chromosome aneuploidies. The commercially available testing options go beyond these recommended tests, and prenatal care professionals should be familiar with the tests that their patients may choose despite being beyond the scope of current medical recommendations. This article explains updates in cell-free DNA technology and clinical considerations for prenatal care professionals, recognizing that this is a rapidly changing field of science and health care.

Amniocentesis in pregnancies at or beyond 24 weeks: an international multicenter study

BACKGROUND

Amniocentesis for genetic diagnosis is most commonly done between 15 and 22 weeks of gestation but can be performed at later gestational ages. The safety and genetic diagnostic accuracy of amniocentesis have been well-established through numerous large-scale multicenter studies for procedures before 24 weeks, but comprehensive data on late amniocentesis remain sparse.

OBJECTIVE

To evaluate the indications, diagnostic yield, safety, and maternal and fetal outcomes associated with amniocentesis performed at or beyond 24 weeks of gestation.

STUDY DESIGN

We conducted an international multicenter retrospective cohort study examining pregnant individuals who underwent amniocentesis for prenatal diagnostic testing at gestational ages between 24w0d and 36w6d. The study, spanning from 2011 to 2022, involved 9 referral centers. We included singleton or twin pregnancies with documented outcomes, excluding cases where other invasive procedures were performed during pregnancy or if amniocentesis was conducted for obstetric indications. We analyzed indications for late amniocentesis, types of genetic tests performed, their results, and the diagnostic yield, along with pregnancy outcomes and postprocedure complications.

RESULTS

Of the 752 pregnant individuals included in our study, late amniocentesis was primarily performed for the prenatal diagnosis of structural anomalies (91.6%), followed by suspected fetal infection (2.3%) and high-risk findings from cell-free DNA screening (1.9%). The median gestational age at the time of the procedure was 28w5d, and 98.3% of pregnant individuals received results of genetic testing before birth or pregnancy termination. The diagnostic yield was 22.9%, and a diagnosis was made 2.4 times more often for fetuses with anomalies in multiple organ systems (36.4%) compared to those with anomalies in a single organ system (15.3%). Additionally, the diagnostic yield varied depending on the specific organ system involved, with the highest yield for musculoskeletal anomalies (36.7%) and hydrops fetalis (36.4%) when a single organ system or entity was affected. The most prevalent genetic diagnoses were aneuploidies (46.8%), followed by copy number variants (26.3%) and monogenic disorders (22.2%). The median gestational age at delivery was 38w3d, with an average of 59 days between the procedure and delivery date. The overall complication rate within 2 weeks postprocedure was 1.2%. We found no significant difference in the rate of preterm delivery between pregnant individuals undergoing amniocentesis between 24 and 28 weeks and those between 28 and 32 weeks, reinforcing the procedure's safety across these gestational periods.

CONCLUSION

Late amniocentesis, at or after 24 weeks of gestation, especially for pregnancies complicated by multiple congenital anomalies, has a high diagnostic yield and a low complication rate, underscoring its clinical utility. It provides pregnant individuals and their providers with a comprehensive diagnostic evaluation and results before delivery, enabling informed counseling and optimized perinatal and neonatal care planning.

Advancements of non-invasive prenatal testing: the role of obstetricians

Since its debut in 2011, Non-Invasive Prenatal Testing (NIPT) has continually demonstrated its effectiveness in detecting an expanding number of diseases. NIPT offers a less invasive approach to prenatal chromosomal disease screening, providing prospective parents with vital information to better prepare for their potential pregnancy outcomes. NIPT was primarily designed for screening trisomy 13, 18, and 21. However, its scope has since broadened to encompass microdeletions and autosomal dominant monogenic diseases. Conversely, the normalization of NIPT can have unintended consequences. Some patients opt for NIPT without any medical indications, driven by a desire to remain cautious. This over-screening for chromosomal abnormalities can exacerbate pregnancy-related anxiety, as individuals might feel pressured into taking the test unnecessarily. While NIPT can be highly successful when conducted correctly, it is not infallible, and obstetricians play a crucial role in managing patient expectations. This includes providing genetic counseling to individuals with relevant genetic information regarding their personal and family histories. In the context of NIPT, a bioinformatics analysis is performed on a cell-free DNA (cfDNA) sample extracted from the mother's placenta to determine the fetal fraction (FF). This FF measurement is vital for quality control and ensuring statistical confidence in the test results. Raising awareness among clinicians about the significance of FF enhances patient care and alleviate concerns about the possibility of failed NIPT. This paper aims to explore the ongoing debates and more specifically the significance and pitfalls of NIPT on a psychosocial and ethical scale, all while highlighting the importance of genetic counseling.

Prospective Investigation of Optical Genome Mapping for Prenatal Genetic Diagnosis

BACKGROUND

Optical genome mapping (OGM) is a novel assay for detecting structural variants (SVs) and has been retrospectively evaluated for its performance. However, its prospective evaluation in prenatal diagnosis remains unreported. This study aimed to prospectively assess the technical concordance of OGM with standard of care (SOC) testing in prenatal diagnosis.

METHODS

A prospective cohort of 204 pregnant women was enrolled in this study. Amniotic fluid samples from these women were subjected to OGM and SOC testing, which included chromosomal microarray analysis (CMA) and karyotyping (KT) in parallel. The diagnostic yield of OGM was evaluated, and the technical concordance between OGM and SOC testing was assessed.

RESULTS

OGM successfully analyzed 204 cultured amniocyte samples, even with a cell count as low as 0.24 million. In total, 60 reportable SVs were identified through combined OGM and SOC testing, with 22 SVs detected by all 3 techniques. The diagnostic yield for OGM, CMA, and KT was 25% (51/204), 22.06% (45/204), and 18.14% (37/204), respectively. The highest diagnostic yield (29.41%, 60/204) was achieved when OGM and KT were used together. OGM demonstrated a concordance of 95.56% with CMA and 75.68% with KT in this cohort study.

CONCLUSIONS

Our findings suggest that OGM can be effectively applied in prenatal diagnosis using cultured amniocytes and exhibits high concordance with SOC testing. The combined use of OGM and KT appears to yield the most promising diagnostic outcomes.

Performance of cell-free DNA testing for common fetal trisomies in triplet pregnancies

OBJECTIVE

In singleton pregnancies, the use of cell-free DNA (cfDNA) analysis as a screening test for common fetal trisomies has spread worldwide though we still lack sufficient data for its use in triplet pregnancies. The objective of this study is to assess the performance of cfDNA testing in detecting fetal aneuploidies in triplet pregnancies as a first-tier test.

METHOD

We performed a retrospective cohort study including data from pregnant women with a triplet pregnancy who underwent cfDNA testing between May 1, 2017, and January 15, 2020. cfDNA was obtained by massive parallel sequencing (VeriSeq NIPT solution; Illumina®). The objectives of the study were to assess the diagnostic performance of cfDNA testing for trisomy 21 (T21) (primary outcome), trisomy 18 (T18) and 13 (secondary outcomes).

RESULTS

During the study period, cfDNA testing was performed in 255 women with triplet pregnancy, of which 165 (64.7%) had a neonatal outcome available. Three tests were positive for T21, one of which was confirmed by an antenatal karyotype, and the other was confirmed at birth. The third case did not undergo an invasive procedure and was not confirmed at birth (false positive). In one case, cfDNA testing was positive for T18 and was confirmed by an antenatal karyotype. There were no cases of trisomy 13 in the cohort. The no-call rate was 2.4% at first sampling. Fifty-eight (22.7%) women had embryo reduction, which in 40 (69%) of whom was performed after the cfDNA test result.

CONCLUSION

cfDNA testing could be offered as primary screening for main fetal aneuploidies in triplet pregnancies after provision of appropriate patient information.

Chromosome balanced translocation in newborn fetus founded during prenatal diagnosis: Three cases reports

RATIONALE

Because of the normal phenotype, carriers of specific chromosomal translocations are often diagnosed only after their development of associated malignancies, recurrent miscarriages, and reproductive difficulties. In this paper, we report primary balanced fetal chromosomal translocations by performing the necessary invasive prenatal diagnosis in couples with previous malformations coupled with prenatal testing suggesting a high risk for trisomy 21.

PATIENT CONCERNS

Case 1 and Case 2 couples had malformed children, and Case 3 couples had a high risk of trisomy 21 on noninvasive preconception serological testing.

DIAGNOSIS AND INTERVENTION

A balanced chromosomal translocation diagnosis was confirmed by karyotyping of fetal cells obtained by amniocentesis.

OUTCOMES

All 3 couples decided to continue their pregnancies after learning about the consequences of the chromosomal abnormalities. Approximately a year after the children were born, the staff of the Prenatal Diagnostic Center followed up with a phone call and found that the children physical development and intelligence were normal.

LESSON

This case report reports healthy chromosomal balanced translocation newborns born to couples with poor maternal history and couples with abnormalities suggested by preconception testing, and followed up with the newborns to provide some experience in prenatal diagnosis and genetic counseling for chromosomal balanced translocations.

Preterm prelabor rupture of membranes after first-trimester chorionic villus sampling: A case report and review of the literature

Rupture of membranes in the first trimester is extremely rare. Generally at this gestational age, rupture is a complication of invasive genetic testing. Little is known about the complications or sequelae of such an occurrence and therefore the management options are limited. This article reports the case of a 35-year-old woman who had rupture of membranes after chorionic villus sampling in the first trimester; it describes her pregnancy course and eventual positive outcome. Regardless of gestational age at time of fluid loss, treatment options are limited. This article reviews the evidence regarding first-trimester rupture and the outcomes of expectant management.

Prenatal Testing for Variants in Genes Associated with Hereditary Cancer Risk: Laboratory Experience and Considerations

Prenatal molecular genetic testing for familial variants that cause inherited disorders has been performed for decades and is accepted as standard of care. However, the spectrum of genes considered for prenatal testing is expanding because of genetic testing for hereditary cancer risk (HCR) and inclusion of conditions with associated cancer risk in carrier screening panels. A few of these disorders, such as ataxia telangiectasia and Bloom syndrome, include increased cancer risk as part of the phenotype, already meet professional guidelines for prenatal testing, and may be associated with increased cancer risk in heterozygous carriers. In addition, recent studies implicate heterozygosity for variants in lysosomal storage disease genes in HCR etiology. Currently, there is no specific professional guidance regarding prenatal testing for HCR. To determine the prevalence of such testing, we reviewed 1345 consecutive prenatal specimens received in our laboratory for familial variant-specific testing and identified 65 (4.8%) with a known or likely HCR component, plus 210 (15.6%) for lysosomal storage disease. These specimens were classified into five distinct categories for clarity and to enable evaluation. Our experience assessing prenatal specimens for variants associated with HCR, with or without a constitutional phenotype, provides metrics for and contributes to the points to consider in prenatal testing for HCR.

Prenatal whole-exome sequencing in fetuses with increased nuchal translucency

BACKGROUND

Increased nuchal translucency (NT) is associated with an increased risk for genetic disorders. The aim of this study was to investigate the value of whole-exome sequencing (WES) in detecting genetic abnormalities for fetuses with isolated first-trimester increased NT.

METHODS

After the exclusion of aneuploidies and pathogenic copy number variants (CNVs) by quantitative fluorescent polymerase chain reaction (QF-PCR) and chromosomal microarray analysis (CMA), WES was performed on 63 fetuses with isolated first-trimester increased NT (≥3.5 mm).

RESULTS

Overall, WES yielded a 4.8% (3/63) diagnostic rate for fetuses with isolated increased NT. Pathogenic variants were identified in 37.5% (3/8) fetuses that developed additional structural anomalies later in gestation, and no pathogenic variants were detected in increased NT that resolved or remained isolated throughout the pregnancy.

CONCLUSION

This study provides powerful evidence to offer prenatal WES for increased NT only when additional abnormalities are present. Early detailed ultrasound to detect emerging anomalies can help physicians offer prenatal WES to fetuses with a greater likelihood of diagnosis.

A call for public funding of invasive and non-invasive prenatal testing

For decades, prenatal screening and genetic testing strategies were limited, requiring less complex decisions. Recently, however, several new advanced technologies were introduced, including chromosomal microarray analysis (CMA) and non-invasive prenatal screening (NIPS), bringing about the need to choose the most appropriate testing for each pregnancy. A worrisome issue is that opposed to the wide implementation and debates over public funding of NIPS, currently invasive testing is still recommended only in selected pregnancies with increased risk for chromosomal aberrations (according to screening tests or sonographic anomalies). This current decision-making regarding public funding for invasive and screening testing might compromise informed consent and patient's autonomy. In this manuscript, we compare several characteristics of CMA vs. NIPS, namely: the accuracy and the diagnostic scope, the risks for miscarriage and for clinically uncertain findings, the timing for testing, and pretest counselling. We argue that it must be recognized that one size might not fit all, and suggest that both options should be presented to all couples through early genetic counseling, with public funding for the specific selected test.

Obstetrical outcomes following amniocentesis performed after 24 weeks of gestation: A systematic review and meta-analysis

To evaluate obstetrical outcomes for women having late amniocentesis (on or after 24 weeks). Electronic databases were searched from inception to January 1st, 2023. The obstetrical outcomes evaluated were gestational age at delivery, preterm birth (PTB) < 37 weeks, PTB within 1 week from amniocentesis, premature prelabor rupture of membranes (pPROM), chorionamnionitis, placental abruption, intrauterine fetal demise (IUFD) and termination of pregnancy (TOP). The incidence of PTB <37 weeks was 4.85% (95% CI 3.48-6.56), while the incidence of PTB within 1 week was 1.42% (95% CI 0.66-2.45). The rate of pPROM was 2.85% (95% CI 1.21-3.32). The incidence of placental abruption was 0.91% (95% CI 0.16-2.25), while the rate of IUFD was 3.66% (95% CI 0.00-14.04). The rate of women who underwent TOP was 6.37% (95%CI 1.05-15.72). When comparing amniocentesis performed before or after 32 weeks, the incidence of PTB within 1 week was 1.48% (95% CI 0.42-3.19) and 2.38% (95% CI 0.40-5.95). Amniocentesis performed late after 24 weeks of gestation is an acceptable option for patients needing prenatal diagnosis in later gestation.

Prenatal Screening for Microdeletions and Rare Autosomal Aneuploidies

Noninvasive prenatal screening with cell-free DNA is now considered a first-line screening for common aneuploidies. Advancements in existing laboratory techniques now allow to interrogate the entirety of the fetal genome, and many commercial laboratories have expanded their screening panels to include screening for rare autosomal aneuploidies and copy number variants. Here, we review the currently available data on the performance of fetal cell-free DNA to detect rare autosomal aneuploidies and copy number variants that are associated with clinically significant microdeletion and microduplication syndromes and the current position of medical societies on routine screening for these syndromes.

Viral Hepatitis in Pregnancy: ACOG Clinical Practice Guideline No. 6

PURPOSE

The purpose of this document is to describe the specific types of viral hepatitis, their implications during pregnancy, the risk of perinatal transmission, and issues related to both treatment and prevention of infection.

TARGET POPULATION

Pregnant or postpartum women and individuals who screen positive for viral hepatitis infection. The onset of these conditions may have predated the perinatal period or may have occurred for the first time in pregnancy or the first year postpartum.

METHODS

This guideline was developed using an a priori protocol in conjunction with a writing team consisting of one specialist in obstetrics and gynecology appointed by the ACOG Committee on Clinical Practice Guidelines-Obstetrics and one external subject matter expert. ACOG medical librarians completed a comprehensive literature search for primary literature within Cochrane Library, Cochrane Collaboration Registry of Controlled Trials, EMBASE, PubMed, and MEDLINE. Studies that moved forward to the full-text screening stage were assessed by two authors from the writing team based on standardized inclusion and exclusion criteria. Included studies underwent quality assessment, and a modified GRADE (Grading of Recommendations Assessment, Development, and Evaluation) evidence-to-decision framework was applied to interpret and translate the evidence into recommendation statements.

RECOMMENDATIONS

This Clinical Practice Guideline includes recommendations on hepatitis B virus and hepatitis C virus screening in pregnancy; prepregnancy, antepartum, intrapartum, and postpartum management for patients with hepatitis B virus infection or hepatitis C virus infection; management of accidental and occupational exposure to hepatitis B virus or hepatitis C virus in pregnant health care workers; and hepatitis A virus and hepatitis B virus vaccination in pregnancy. Recommendations are classified by strength and evidence quality. Ungraded Good Practice Points are included to provide guidance when a formal recommendation could not be made because of inadequate or nonexistent evidence.

A chromosomal microarray analysis-based laboratory algorithm for the detection of genetic etiology of early pregnancy loss

Background: Chromosomal abnormalities are a major cause of early pregnancy loss. However, models synthesizing existing genetic technologies to improve pregnancy outcomes are lacking. We aim to provide an integrated laboratory algorithm for the genetic etiology of couples who experienced pregnancy loss. Methods: Over a 6-year period, 3,634 products of conception (POCs) following early pregnancy loss were collected. The clinical outcomes from a laboratory algorithm based on single nucleotide polymorphism (SNP) array, fluorescence in situ hybridization (FISH), and parental chromosomal karyotyping assays were comprehensively evaluated. Results: In total, 3,445 of 3,634 (94.8%) POCs had no maternal-cell contamination. Of those POCs, the detection rate of abnormal results was 65.2% (2,247/3,445), of which 91.2% (2,050/2,247) had numerical chromosomal abnormalities, 2.7% (60/2,247) had copy-number variations (CNVs) ≥10 Mb, 2.7% (61/2,247) had CNVs of terminal deletion and duplication, 2.8% (62/2,247) had CNVs <10 Mb, and 0.6% (14/2,247) had uniparental disomy. Furthermore, FISH confirmed 7 of the 60 POCs with mosaic aneuploids below 30% based on the SNP array results as tetraploid. Of the 52 POCs with CNVs of terminal deletion and duplication, 29 couples had balanced rearrangements based on chromosomal karyotyping. Conclusion: The integrated SNP array-based algorithm combined with optional FISH and parental chromosomal karyotyping is an effective laboratory testing strategy, providing a comprehensive and reliable genetic investigation for the etiology of miscarriage, regardless of the number of miscarriages and the method of conception.

Laboratory performance of genome-wide cfDNA for copy number variants as compared to prenatal microarray

BACKGROUND

Noninvasive prenatal testing (NIPT) allows for screening of fetal aneuploidy and copy number variants (CNVs) from cell-free DNA (cfDNA) in maternal plasma. Professional societies have not yet embraced NIPT for fetal CNVs, citing a need for additional performance data. A clinically available genome-wide cfDNA test screens for fetal aneuploidy and CNVs larger than 7 megabases (Mb).

RESULTS

This study reviews 701 pregnancies with "high risk" indications for fetal aneuploidy which underwent both genome-wide cfDNA and prenatal microarray. For aneuploidies and CNVs considered 'in-scope' for the cfDNA test (CNVs ≥ 7 Mb and select microdeletions), sensitivity and specificity was 93.8% and 97.3% respectively, with positive and negative predictive values of 63.8% and 99.7% as compared to microarray. When including 'out-of-scope' CNVs on array as false negatives, the sensitivity of cfDNA falls to 48.3%. If only pathogenic out-of-scope CNVs are treated as false negatives, the sensitivity is 63.8%. Of the out-of-scope CNVs identified by array smaller than 7 Mb, 50% were classified as variants of uncertain significance (VUS), with an overall VUS rate in the study of 2.29%.

CONCLUSIONS

While microarray provides the most robust assessment of fetal CNVs, this study suggests that genome-wide cfDNA can reliably screen for large CNVs in a high-risk cohort. Informed consent and adequate pretest counseling are essential to ensuring patients understand the benefits and limitations of all prenatal testing and screening options.

Experience in prenatal genetic testing and reproductive decision-making for monogenic disorders from a single tertiary care genetics clinic in a low-middle income country

OBJECTIVES

Explore health-care seeking behaviour among couples with pregnancies at-risk of monogenic disorders and compare time duration for obtaining Prenatal Genetic Test (PGT) results based on (i) amniocentesis and Chorionic Villus Sampling (CVS) (ii) in-house testing and out-sourced testing. Report the spectrum of monogenic disorders in our cohort.

METHODS

Medical records of women consulting prenatal genetic counselling clinic at Aga Khan University Hospital, Karachi from December-2015 to March-2021 with history of miscarriage or a monogenic disorder in previous children were reviewed.

RESULTS

Forty-three pregnancies in 40 couples were evaluated, 37(93%) were consanguineous. Twenty-five (63%) couples consulted before and 15(37%) after conception. Thirty-one (71%) pregnancies underwent CVS at the mean gestational age of 13-weeks and 6-days ± 1-week and 3-days and amniocentesis at 16-weeks and 2-days ± 1-week and 4-days. PGT for 30 (70%) pregnancies was outsourced. The mean number of days for in-house PGT was 16.92 ± 7.80 days whereas for outsourced was 25.45 ± 7.7 days. Mean duration from procedure to PGT result was 20.55 days after CVS compared to 28.75 days after amniocentesis. Eight (18%) fetuses were homozygous for disease-causing variant for whom couples opted for termination of pregnancy (TOP). Twenty-six monogenetic disorders were identified in 40 families.

CONCLUSION

Proactive health-care seeking behaviour and TOP acceptance is present amongst couples who have experienced a genetic disorder.

Challenges and Pragmatic Solutions in Pre-Test and Post-Test Genetic Counseling for Prenatal Exome Sequencing

The yield of genetic prenatal diagnosis has been notably improved by introducing whole genome chromosomal microarray (CMA) and prenatal exome sequencing (pES). However, together with increased numbers of diagnoses made, the need to manage challenging findings such as variants of unknown significance (VUS) and incidental findings (IF) also increased. We have summarized the current guidelines and recommendations and we have shown current solutions used in our tertiary center in the Netherlands. We discuss four of the most common clinical situations: fetus with normal pES results, fetus with a pathogenic finding explaining the fetal phenotype, fetus with a variant of uncertain clinical significance fitting the phenotype and fetus with a variant leading to an incidental diagnosis. Additionally, we reflect on solutions in order to facilitate genetic counseling in an NGS-era.

Using single nucleotide polymorphism array for prenatal diagnosis in a large multicenter study in Southern China

Numerous studies have evaluated the use of single nucleotide polymorphism array (SNP-array) in prenatal diagnostics, but very few have evaluated its application under different risk conditions. Here, SNP-array was used for the retrospective analysis of 8386 pregnancies and the cases were categorized into seven groups. Pathogenic copy number variations (pCNVs) were found in 699 (8.3%, 699/8386) cases. Among the seven different risk factor groups, the non-invasive prenatal testing-positive group had the highest pCNVs rate (35.3%), followed by the abnormal ultrasound structure group (12.8%), and then the chromosomal abnormalities in the couples group (9.5%). Notably the adverse pregnancy history group presented with the lowest pCNVs rate (2.8%). Further evaluation of the 1495 cases with ultrasound abnormalities revealed that the highest pCNV rates were recorded in those cases with multiple system structure abnormalities (22.6%), followed by the groups with skeletal system (11.6%) and urinary system abnormalities (11.2%). A total of 3424 fetuses with ultrasonic soft markers were classified as having one, two, or three ultrasonic soft markers. The different pCNV rates in the three groups were statistically significant. There was little correlation between pCNVs and a previous history of adverse pregnancy outcomes, suggesting that genetic screening under these conditions should be evaluated on a case-by-case basis.

Positive cfDNA screening results for 22q11.2 deletion syndrome—Clinical and laboratory considerations

Introduction: Non-invasive prenatal screening (NIPS) via cell-free DNA (cfDNA) screens for fetal chromosome disorders using maternal plasma, including 22q11.2 deletion syndrome (22q11.2DS). While it is the commonest microdeletion syndrome and has potential implications for perinatal management, prenatal screening for 22q11.2DS carries some inherent technical, biological, and counseling challenges, including varying deletion sizes/locations, maternal 22q11.2 deletions, confirmatory test choice, and variable phenotype.

Materials and methods: This study addresses these considerations utilizing a retrospective cohort of 307 samples with screen-positive 22q11.2 NIPS results on a massively parallel sequencing (MPS) platform.

Results: Approximately half of the cases reported ultrasound findings at some point during pregnancy. In 63.2% of cases with diagnostic testing, observed positive predictive values were 90.7%–99.4%. cfDNA identified deletions ranging from &lt;1 Mb to 3.55 Mb, with significant differences in confirmed fetal versus maternal deletion sizes; estimated cfDNA deletion size was highly concordant with microarray findings. Mosaicism ratio proved useful in predicting the origin of a deletion (fetal versus maternal). Prediction of deletion size, location, and origin may help guide confirmatory testing.

Discussion: The data shows that MPS-based NIPS can screen for 22q11.2DS with a high PPV, and that collaboration between the laboratory and clinicians allows consideration of additional metrics that may guide diagnostic testing and subsequent management.

Feingold syndrome type 1: a rare cause of fetal microcephaly (prenatal diagnosis)

We report a case of fetal microcephaly found during the second trimester ultrasound and confirmed by further ultrasound scans and fetal MRI. The array comparative genomic hybridisation analysis of the fetus and the male parent showed a 1.5 Mb deletion overlapping the Feingold syndrome region, an autosomal dominant syndrome that can cause microcephaly, facial/hand abnormalities, mild neurodevelopmental delay and others. This case illustrates the need for a detailed investigation by a multidisciplinary team to provide prenatal counselling regarding a postnatal outcome to the parents and orient their decision towards the continuation or termination of pregnancy.

Implications for Prenatal Genetic Testing in the United States After the Reversal of Roe v Wade

Prenatal genetic screening and diagnostic testing should be offered to every pregnant individual, with methods varying based on gestational age. Since Roe v Wade was overturned in June 2022, many states have implemented gestational age-based abortion restrictions. It is critical that reproductive health care professionals be aware of the interaction between the timing of genetic screening and diagnostic testing and the availability of legal abortion services in their state. We examined individual state abortion restrictions per publicly available data from The New York Times and the Guttmacher Institute and reviewed which genetic screening and diagnostic tests could be performed to provide results in time for individuals to decide whether to terminate their pregnancies legally in each state. As of December 11, 2022, 14 states have restrictions in which no diagnostic testing could be completed before gestational age-based cutoffs. Gestational age-based abortion restrictions may also influence a patient to favor chorionic villous sampling (CVS) over amniocentesis. There are two states, Florida and Arizona, where CVS would be feasible before the state's gestational age limit on abortion but amniocentesis would not. Both CVS and amniocentesis are feasible in 35 states, with legal challenges pending in 8 of the 35. Seven states specifically prohibit abortion for fetuses with genetic abnormalities. Clinicians may be placed in the suboptimal position of counseling patients with screening results alone before the gestational age-based ban in their state. There are several potential downstream consequences of gestational age-based termination restrictions for current genetic screening and testing paradigms, from adjustments to counseling options to potentially higher CVS procedure rates. Clinicians should be prepared for practice patterns to change to best serve patients in this evolving legal context.

Feasibility and Acceptability of At-Home Routine Pregnancy Testing in the United States: A Pilot Study

OBJECTIVES

We aimed to investigate the acceptability of regular self-testing among people with increased risk for delayed pregnancy recognition when provided with free at-home pregnancy tests and to explore the feasibility of this intervention among a larger sample.

MATERIALS AND METHODS

In 2019-2020, we recruited participants across the United States by using flyers posted online and in community settings and abortion clinics. We purposively sampled people with pregnancy capacity who were 18 to 24 years old, had irregular menses, or had a recent second-trimester abortion. Participants were mailed pregnancy tests and instructions. Participants received text message reminders to test monthly over a 3-month period and were asked to text back results. Participants also completed online surveys at baseline, after 1 month, and after 3 months. A purposive subsample of participants was selected to participate in semi-structured interviews. Interviews were analyzed using thematic analysis of interview guide topics and emergent themes.

RESULTS

61 participants were enrolled. Fifty-four participants (90%) responded to the text reminders and 52 (85%) reported testing in all 3 months. Fifty-eight (95%) said tests were easy to use, 59 (97%) said the results were clear, and all participants found it convenient to text their results. Fourteen participants completed qualitative interviews. All described continuing to test after the study and indicated high acceptability for text reminders. Interviewees described convenience and cost as primary benefits for preferring at-home pregnancy testing.

CONCLUSIONS

Regular self-testing and texting results is feasible and acceptable to participants provided with free at-home urine pregnancy tests. These results can inform future studies designed to investigate the effect of regular self-testing on timing of pregnancy detection to facilitate early entry to prenatal care or early abortion.

The management of congenital adrenal hyperplasia during preconception, pregnancy, and postpartum

Congenital adrenal hyperplasia (CAH) is a group of autosomal recessive disorders of steroidogenesis of the adrenal cortex, most commonly due to 21-hydroxylase deficiency caused by mutations in the CYP21A2 gene. Although women with CAH have decreased fecundity, they are able to conceive; thus, if pregnancy is not desired, contraception options should be offered. If fertility is desired, women with classic CAH should first optimize glucocorticoid treatment, followed by ovulation induction medications and gonadotropins if needed. Due to the possible pregnancy complications and implications on the offspring, preconception genetic testing and counseling with a high-risk obstetrics specialist is recommended. For couples trying to avoid having a child with CAH, care with a reproductive endocrinology and infertility specialist to utilize in vitro fertilization can be offered, with or without preimplantation genetic testing for monogenic disorders. Prenatal screening and diagnosis options during pregnancy include maternal serum cell free-DNA for sex of the baby, and chorionic villus sampling and amniocentesis for diagnosis of CAH. Pregnant women with classic CAH need glucocorticoids to be adjusted during the pregnancy, at the time of delivery, and postpartum, and should be monitored for adrenal crisis. Maternal and fetal risks may include chorioamnionitis, maternal hypertension, gestational diabetes, cesarean section, and small for gestational age infants. This review on CAH due to 21-hydroxylase deficiency highlights reproductive health including genetic transmission, contraception options, glucocorticoid management, fertility treatments, as well as testing, antenatal monitoring, and management during pregnancy, delivery, and postpartum.

Prenatal exome and genome sequencing for fetal structural abnormalities

As prenatal exome sequencing becomes integrated into clinical care, it is critical that providers caring for women with fetal anomalies recognize not only the benefits, but also the challenges and considerations related to this technology. This overview of prenatal sequencing includes information about indications for sequencing, methods, diagnostic yield, clinical utility, variant interpretation, ethical considerations and dilemmas, practical considerations (ie, turnaround time and cost), pre- and posttest counseling points, and psychological impact of testing on families.

Interventions addressing genetic disease burdens within selected countries in the MENA region: a scoping review

BACKGROUND

The MENA region is disproportionately affected by genetic disease. The aim of this research is to scope the region for evidence of genetic services and public health interventions to identify geographic gaps, and to provide a descriptive overview of interventions to identify knowledge gaps.

METHODS

This study is conducted as a scoping review and follows the Arksey & O'Malley scoping review framework.

RESULTS

Seventy-six articles spanning 16 MENA nations met inclusion criteria. Studies included interventions in the form of genetic service provision (n=28), as well as comprehensive programs including pilot programs (n=7), community-based genetics programs (n=6) national-level prevention programs (n=18), and national-level mandatory programs (n=17).

CONCLUSIONS

There is an imbalanced response to genetic disease burdens across the MENA region. More research is warranted where interventions are scarce, particularly to inform development of pilot community-based programs. There is also a need for better monitoring and evaluation of existing nation-wide programs.

An Ethical Argument for Health Insurance Coverage of Paternal Prenatal Genetic Testing

Despite evidence-based recommendations from the American College of Obstetricians and Gynecologists and the American College of Medical Genetics to offer prenatal genetic carrier screening for reproductive partners, partner carrier screening or genetic testing is inconsistently covered by pregnant patients' health insurance plans. Health policies that exclude reproductive partners from insurance coverage for prenatal carrier screening or genetic testing contradict multiple ethical principles and can even contribute to adverse maternal-child health outcomes. Incomplete or missing information regarding partner carrier status can lead to costly, invasive, and potentially risky interventions for the pregnant patient that can be avoided by a simple and less expensive blood test in the reproductive partner. Lack of information regarding carrier status also harms the neonate by obviating an opportunity for early detection and treatment of potential medical complications. Insurance policies that exclude coverage for paternal genetic testing perpetuate the disproportionate burdens of pregnancy care and risk shouldered by pregnant people. To rectify these ethical dilemmas, partner carrier screening and genetic testing should be considered and covered as routine components of obstetric health care that are covered by health insurance.

Voices on Zika: Reproductive Autonomy and Shared Decision-Making During an Evolving Epidemic

INTRODUCTION

We aimed to understand the degree to which pregnant individuals exposed to emerging infections, such as Zika, are engaged by providers in shared decision-making and explore potential barriers to inform strategies to improve care for those most at risk for inequities. Studies have demonstrated that Latinx and Black people are less likely to engage in shared decision-making and are less engaged by providers. Limited research explores factors impacting shared decision-making in prenatal care and in the setting of recent epidemics.

METHODS

We conducted an exploratory qualitative study of individuals eligible for prenatal screening owing to Zika exposure during pregnancy. Given an established connection between autonomy and shared decision-making, we used the Reproductive Autonomy Scale and the Three Talk Model for shared decision-making to inform our semistructured interview guide. Interviews were conducted in Spanish or English. and participants were recruited from a federally qualified health center and a tertiary care obstetric clinic until thematic saturation was achieved. Interviews were recorded, translated, and transcribed and two coders used modified grounded theory to generate themes.

RESULTS

We interviewed 18 participants from May to December 2017. Participant narratives demonstrated reproductive autonomy in pregnancy decision-making, with decision support from families, fatalism in pregnancy planning, and limited engagement by providers around decisions and implications of Zika virus testing. Hierarchy in provider dynamics, perceived stigma around emigration and travel, and language barriers impacted participant engagement in shared decision-making.

CONCLUSIONS

Participants demonstrated personal autonomy in reproductive decision-making, but demonstrated limited engagement in shared decision-making with regard to prenatal Zika testing. Provider promotion of shared decision-making using culturally centered decision tools to elicit underlying beliefs and deepen context for option, choice, and decision talk is critical in prenatal counseling to support equitable outcomes during evolving pandemics.

Genetic studies in isolated bilateral clubfoot detected by prenatal ultrasound

OBJECTIVE

To evaluate the contribution of genetic investigations in case of isolated bilateral clubfoot detected by routine prenatal ultrasound. Pathogenic Copy Number Variations is about 3.9% in fetuses with isolated clubfoot (uni- or bilateral). We hypothesize that this rate could be higher in a homogenous group of fetuses with bilateral clubfoot.

METHODS

This retrospective single-center study included all women referred to our fetal-medicine center between 2013 and 2020 after ultrasound detection of isolated bilateral clubfoot. Genetic counseling was offered in which the woman was offered an amniocentesis for CMA and targeted investigation for Prader-Willi Syndrome (PWS), Steinert's disease and Spinal Muscular Atrophy (SMA).

RESULTS

34 women were referred, 18 of them consented to undergo genetic studies by amniocentesis (18/34; 52.9%). Pathogenic copy number variations (CNVs) were found in 2/18 (11.1%) of cases. One of these CNVs was directly linked to the clubfoot pathology (a deletion in 5q31.1 containing PITX1 gene). Four fetuses (4/18, 22.2%) had variants of unknown significance (VUS). No PWS, SMA or Steinert's disease was found. No case diagnosed with isolated clubfoot prenatally had additional anomalies postnatally.

CONCLUSIONS

In the case of bilateral isolated clubfoot detected at the antenatal ultrasound, invasive prenatal testing should be offered, and if accepted, a CMA should be done, as pathogenic variations were observed in up to 11.1% of women who got amniocentesis. The findings of this study do not support the systematic recommendation of molecular studies for PWS, SMA, Steinert's disease.

Prenatal genetic testing 2: diagnostic tests

PURPOSE OF REVIEW

Prenatal genetic testing can be divided into two categories: screening and diagnosis. Prenatal genetic screening tests are used to assess carrier status or as a fetal risk assessment for a particular genetic disorder [1]. Prenatal genetic diagnostic testing is used to diagnose particular genetic conditions with as much certainty as possible [1,2]. This review will focus on the diagnostic side of prenatal genetic testing.

RECENT FINDINGS

Next generation sequencing (NGS) has revolutionized prenatal genetic diagnostic testing. NGS methods are becoming more advanced and accurate as more genetic information is being linked to genetic conditions.

SUMMARY

Prenatal genetic diagnostic testing involves clinicians invasively obtaining tissue via amniocentesis or chorionic villus sampling to identify if a fetus has a genetic condition. This testing has traditionally been done through fluorescence in-situ hybridization, karyotype, or chromosomal microarray analysis. However, genetic testing is in a time of rapid technologic expansion and new methods like NGS, which includes targeted gene panels, whole exome sequencing, and whole genome sequencing are being used too. In this time of growth, it is important that providers educate themselves on the research support and indication behind each type of genetic diagnostic test.

Increased use of diagnostic testing after increased nuchal translucency: The influence of non-invasive prenatal testing and chromosomal microarray

OBJECTIVE

The utilization of non-invasive prenatal testing (NIPT) and chromosomal microarray (CMA) has significantly altered the options for testing following the diagnosis of an increased nuchal translucency (NT). This study defines the rates of utilization of diagnostic testing in the pre-NIPT, pre-CMA, and post-CMA eras.

METHODS

We retrospectively examined NT scans performed in our department from January 2010 to December 2020 and identified all NTs ≥3.0 mm for analysis. We divided our data into three distinct periods (2010-2012, 2013-2016, and 2017-2020) corresponding to our institutional practice shifts in recommending and offering use of NIPT (2013) and CMA (2016), respectively.

RESULTS

689 patients with NT ≥ 3.0 mm met inclusion criteria in our study, of which 355 (51.5%) individuals underwent diagnostic testing and 334 (48.5%) did not. There was a significant decline in rates of diagnostic testing with NIPT (2013), which has returned to pre-NIPT levels with the availability of microarray.

CONCLUSIONS

Since the routine use of CMA (2016), the rates of diagnostic testing for increased NT have returned to pre-NIPT levels. This study validates data suggesting an initial decline in the rates of diagnostic testing following abnormal NT but suggests that the decline may be reversing in the post-CMA era due to a rise in rates of chorionic villus sampling.

Factors associated with US and Canadian genetic counselors' testing decisions during pregnancy

Decision-making regarding prenatal screening and diagnostic testing has become more complex as the number of options has increased, with pregnant patients having access to more information about their pregnancies than ever before. Genetic counselors have extensive training in prenatal genetic screening and testing options, but personal decision-making in this well-informed population remains largely unstudied. This study describes the prenatal testing decisions genetic counselors made during their own pregnancies, and the factors identified as important when making those decisions. A web-based, mixed-methods survey was distributed to members of multiple professional societies for genetic counselors. A total of 318 genetic counselors across numerous specialties in the United States and Canada participated in this study. The satisfaction with decision scale was modified and applied to measure participants' decisional satisfaction. In their most recent pregnancies, most genetic counselors pursued carrier screening (77%) and aneuploidy and/or open neural tube defect screening (88%). A minority of genetic counselors (15%) utilized diagnostic testing. Common factors considered when making testing decisions included wanting information that could impact future decisions, test specifics (e.g., accuracy, methodology, and content), and knowledge gained from participants' genetic counseling background. The uptake of diagnostic testing among prenatal genetic counselors was significantly greater (p < 0.05) than the uptake among genetic counselors in other specialties. This informed study population largely self-directed their own prenatal care, leading to high satisfaction with their decisions. Data in this study provide evidence for promoting participation in prenatal screening and testing decision-making to maximize decisional satisfaction.

Do online decision aids reflect new prenatal screening and testing options? An environmental scan and content analysis

Objective

Decision aids have been developed to help prospective parents make informed, shared decisions about medical tests, but these options are rapidly changing. This study aimed to identify and evaluate publicly available decision aids written in English for prospective parents seeking prenatal test information.

Methods

A systematic review process was followed using 3 sources: known decision aid repositories, fetal medicine organisations and Google. The search, screening process, quality assessment, and data extraction was performed by two independent researchers. The quality assessment of the decision aids was based on the International Patient Decision Aids Standards (IPDAS v.4.0).

Results

We identified 13 decision aids, which varied in the screening and diagnostic tests that they discussed. No decision aid met all the IPDAS v.4.0. criteria and no decision aid reported updated risk of miscarriage for amniocentesis and chorionic villus sampling (CVS). There was a lack of decision aids for some common decisions in the prenatal context.

Conclusion

We identified outdated content in current prenatal decision aids. The findings will inform healthcare professionals of the quality of current prenatal decision aids, which may facilitate their patients' informed decision-making about prenatal tests.

Innovation

Considerations for improving future decision aids are outlined.

Workforce Considerations When Building a Precision Medicine Program

This paper describes one healthcare system's approach to strategically deploying genetic specialists and pharmacists to support the implementation of a precision medicine program. In 2013, Sanford Health initiated the development of a healthcare system-wide precision medicine program. Here, we report the necessary staffing including the genetic counselors, genetic counseling assistants, pharmacists, and geneticists. We examined the administrative and electronic medical records data to summarize genetic referrals over time as well as the uptake and results of an enterprise-wide genetic screening test. Between 2013 and 2020, the number of genetic specialists employed at Sanford Health increased by 190%, from 10.1 full-time equivalents (FTEs) to 29.3 FTEs. Over the same period, referrals from multiple provider types to genetic services increased by 423%, from 1438 referrals to 7517 referrals. Between 2018 and 2020, 11,771 patients received a genetic screening, with 4% identified with potential monogenic medically actionable predisposition (MAP) findings and 95% identified with at least one informative pharmacogenetic result. Of the MAP-positive patients, 85% had completed a session with a genetics provider. A strategic workforce staffing and deployment allowed Sanford Health to manage a new genetic screening program, which prompted a large increase in genetic referrals. This approach can be used as a template for other healthcare systems interested in the development of a precision medicine program.

Assessment of a Simplified Cell-Free DNA Method for Prenatal Down Syndrome Screening

Background

Prenatal screening for common trisomies via cell-free (cfDNA) is usually implemented by technologies utilizing massively parallel sequencing, stringent environmental controls, complex bioinformatics, and molecular expertise. An alternative and less complex methodology utilizes rolling circle amplification (RCA). Further evaluation of its performance and related requirements are warranted.

Methods

At 16 sites, women at 10 to 20 weeks gestation provided informed consent, relevant information, and 2 to 3 blood samples. Samples shipped for testing were processed and stored. Women were enrolled at primary cfDNA screening, or following such screening at referral for diagnostic testing. RCA testing occurred post-enrollment, over 11 months. Diagnostic results and delivery notes determined clinical truth. Detection rates were based on confirmed trisomic pregnancies; false-positive rates were based on unaffected pregnancies from the general population.

Results

Detection rate for the common trisomies was 95.9% (117/122, 95% CI, 90.5%–98.5%); overall false-positive rate was 1.00% (22/2,205, 0.65%–1.51%). Test failure rate after repeat testing was 0.04%. When assay standard deviations were below pre-specified levels, the overall false-positive rate was much lower at 0.30% (P &lt; 0.001). Fetal sex calls were correct for 99.7%. One technician analyzed 560 samples over 2 weeks, a rate of 14 000/year.

Conclusions

Our assessment of this simplified cfDNA-based system for prenatal screening for common trisomies performed in a prenatal screening laboratory is encouraging. Improved detection, low failure rates and rapid reporting can be achieved by collecting 2 samples. Future priorities should include achieving higher run precision using a single collection tube.

Clinicaltrials.gov Registration Number: NCT03087357.

Should prenatal chromosomal microarray analysis be offered for isolated ventricular septal defect? A single-center retrospective study from China

Objective

To evaluate the utility of chromosomal microarray analysis (CMA) in fetuses with isolated ventricular septal defect (VSD) and to explore the favorable factors for predicting spontaneous closure of defects.

Methods

The study included 436 singleton pregnancies seen at a referral prenatal diagnosis center, between January 2016 and May 2020, of which 168 fetuses with isolated VSD were diagnosed in the prenatal setting. VSD was classified as an isolated VSD whether it had ultrasound soft markers or not. All patients underwent testing employing quantitative fluorescent polymerase chain reaction (QF-PCR) and CMA as the first-line genetic detection strategies, mainly in amniotic fluid and umbilical blood samples. Rates of chromosomal abnormalities were compared by subgroups of isolated VSD (muscular or perimembranous). Binary logistic regression analysis was performed to predict the independent determinants of spontaneous closure by 2 years.

Results

Overall, the CMA identified clinically significant copy number variations (CNVs) in 7/168 (4.2%) fetuses and variants of unknown significance (VOUS) in 15/168 (8.9%). Muscular and perimembranous VSDs were found in 53.6 and 46.4%, respectively. Clinically significant relevant subchromosomal aberrations were revealed in seven (9.0%) perimembranous VSDs compared with none in 90 muscular defects (P &lt; 0.01). The median initial size of the defect in the muscular VSDs was 2.2(1.8–2.7) mm, as compared to that of 2.8 (2.2–3.2) mm in the perimembranous VSDs group (p = 0.000). In muscular vs. perimembranous VSDs, spontaneous closure occurred more frequently and earlier [40.0 vs. 15.4% in utero (p = 0.000), 61.1 vs. 30.8% at 1-year (p = 0.000), and 75.6 vs. 42.3% at 2-year (P = 0.000)]. Postnatal surgical closure was warranted in 4/90 (4.4%) of the infants with muscular VSDs, as compared to 29/71 (40.8%) with perimembranous defects (p = 0.000). Furthermore, isolated muscular type VSD, smaller defect size, and maternal age of less than 35 years are all positive predictors of spontaneous closure of the defects.

Conclusion

This study highlighted the value of microarray for unbalanced subchromosomal abnormalities in fetuses with isolated VSD, particularly in the perimembranous defects. The detection of an isolated muscular VSD prenatally may be considered a benign or likely benign finding; in contrast, for perimembranous VSD, a prenatal CMA should be offered.

Role of Sonographic Second Trimester Soft Markers in the Era of Cell-Free DNA Screening Options: A Review

Soft markers are sonographic structural, nonspecific signs with little pathological significance, often transient, usually considered as normal variants. However, they may also be associated with chromosomal abnormalities. The most widely examined soft markers include absent or hypoplastic nasal bone (NB), intracardiac echogenic focus (IEF), ventriculomegaly (VM), thickened nuchal fold (NF), choroid plexus cyst (CPC), echogenic bowel, short long bones, and urinary tract dilation (UTD). Although the use of noninvasive prenatal testing (NIPT) has been spreading quickly in maternal–fetal medicine, it is not a diagnostic test and it still remains unavailable or cost-prohibitive for most of the population in many countries. After normal screening test results in the first trimester, there is no uniform consensus regarding the clinical significance of isolated soft markers for aneuploidy. Nowadays, the search for soft markers in an ultrasound is still part of clinical evaluation, and the interpretation of these findings is often a matter of debate. In the present review, we summarize the recent literature about the role of soft markers in the era of NIPT and propose an overview of the different clinical guidelines.

Prenatal diagnosis of Williams-Beuren syndrome by ultrasound and chromosomal microarray analysis

Background

There are a few literature reports of prenatal ultrasound manifestations of Williams-Beuren syndrome. We aimed to explore the prenatal diagnosis of Williams-Beuren syndrome by ultrasound and chromosomal microarray analysis and describe the prenatal ultrasound performance of this syndrome.

Methods

In this retrospective study, we reported eight cases of Williams-Beuren syndrome diagnosed at our prenatal diagnostic center from 2016 to 2021. We systematically reviewed clinical data from these cases, including indications for invasive testing, sonographic findings, QF-PCR results, chromosomal microarray analysis results, and pregnancy outcomes.

Results

In this study, the common ultrasound features were ventricular septal defect (37.5%), intrauterine growth retardation (25%), and aortic coarctation (25%). Moreover, all patients were found to have a common deletion in the Williams-Beuren syndrome chromosome region at the 7q11.23 locus, which contained the elastin gene. Deletion sizes ranged from 1.42 to 2.07 Mb. Seven parents asked for termination of pregnancy, and one patient was lost to follow-up.

Conclusions

This study is the most extensive prenatal study using chromosomal microarray analysis technology for detailed molecular analysis of Williams-Beuren syndrome cases. We reported three cases combined with first-reported ultrasound manifestations. Case 1 was concomitant with multicystic dysplastic kidney and duodenal atresia combined with case 3. Notably, case 4 was combined with multiple cardiovascular malformations: Tetralogy of Fallot, right aortic arch, and supravalvar aortic stenosis. These manifestations expand the intrauterine ultrasound phenotype of Williams-Beuren syndrome in previous literature reports.

Uptake of prenatal genetic diagnosis and termination of pregnancy by Omani Muslim families at risk of genetic disorders: experience over a 9-year period

Studies on the acceptance of prenatal diagnosis and termination of pregnancy for single gene disorders within Islamic societies in the Middle East are limited. A few have examined the attitudes toward pregnancy termination for fetal indications, but a dearth of published data exists on actual behavior and uptake. This study reports on all prenatal diagnosis requests for single gene disorders, from the Sultanate of Oman, over 9 years. A retrospective study was conducted during which the medical records of all women who performed prenatal diagnoses for single gene disorders were reviewed. A total of 148 invasive procedures were performed for 114 families. The total number of yearly requests for prenatal diagnosis increased exponentially from three in 2012 to 21 in 2020. Sixty-four different diagnoses were tested for with the majority being autosomal recessive in nature. Seventy-one percent (28/39) of cases where an affected pregnancy was identified were terminated. Fifty-two of the 114 women (45.6%) repeated prenatal diagnosis in a future pregnancy. Seventy-two couples (63%) were consanguineous parents related as second cousins or closer. The majority of tests performed were for couples from Muscat (27%), Albatinah (27%), and Alsharqiya (20.3%) governorates in Oman. The findings of this study provide evidence that prenatal diagnosis is an acceptable reproductive option to prevent the occurrence of genetic disorders that meet termination eligibility criteria as outlined by the Islamic Jurisprudence (Fiqh) Council Fatwa, among Omani Muslim couples.