Laboratory testing for preconception/prenatal carrier screening: A technical standard of the American College of Medical Genetics and Genomics (ACMG).

Carrier screening has historically assessed a relatively small number of autosomal recessive and X-linked conditions selected based on frequency in a specific subpopulation and association with severe morbidity or mortality. Advances in genomic technologies enable simultaneous screening of individuals for several conditions. The American College of Medical Genetics and Genomics recently published a clinical practice resource that presents a framework when offering screening for autosomal recessive and X-linked conditions during pregnancy and preconception and recommends a tier-based approach when considering the number of conditions to screen for and their frequency within the US population in general. This laboratory technical standard aims to complement the practice resource and to put forth considerations for clinical laboratories and clinicians who offer preconception/prenatal carrier screening.

Prenatal vs postnatal diagnosis of 22q11.2 deletion syndrome: cardiac and noncardiac outcomes through 1 year of age.

BACKGROUND: The 22q11.2 deletion syndrome is the most common microdeletion syndrome and is frequently associated with congenital heart disease. Prenatal diagnosis of 22q11.2 deletion syndrome is increasingly offered. It is unknown whether there is a clinical benefit to prenatal detection as compared with postnatal diagnosis. OBJECTIVE: This study aimed to determine differences in perinatal and infant outcomes between patients with prenatal and postnatal diagnosis of 22q11.2 deletion syndrome. STUDY DESIGN: This was a retrospective cohort study across multiple international centers (30 sites, 4 continents) from 2006 to 2019. Participants were fetuses, neonates, or infants with a genetic diagnosis of 22q11.2 deletion syndrome by 1 year of age with or without congenital heart disease; those with prenatal diagnosis or suspicion (suggestive ultrasound findings and/or high-risk cell-free fetal DNA screen for 22q11.2 deletion syndrome with postnatal confirmation) were compared with those with postnatal diagnosis. Perinatal management, cardiac and noncardiac morbidity, and mortality by 1 year were assessed. Outcomes were adjusted for presence of critical congenital heart disease, gestational age at birth, and site. RESULTS: A total of 625 fetuses, neonates, or infants with 22q11.2 deletion syndrome (53.4% male) were included: 259 fetuses were prenatally diagnosed (156 [60.2%] were live-born) and 122 neonates were prenatally suspected with postnatal confirmation, whereas 244 infants were postnatally diagnosed. In the live-born cohort (n=522), 1-year mortality was 5.9%, which did not differ between groups but differed by the presence of critical congenital heart disease (hazard ratio, 4.18; 95% confidence interval, 1.56-11.18; P<.001) and gestational age at birth (hazard ratio, 0.78 per week; 95% confidence interval, 0.69-0.89; P<.001). Adjusting for critical congenital heart disease and gestational age at birth, the prenatal cohort was less likely to deliver at a local community hospital (5.1% vs 38.2%; odds ratio, 0.11; 95% confidence interval, 0.06-0.23; P<.001), experience neonatal cardiac decompensation (1.3% vs 5.0%; odds ratio, 0.11; 95% confidence interval, 0.03-0.49; P=.004), or have failure to thrive by 1 year (43.4% vs 50.3%; odds ratio, 0.58; 95% confidence interval, 0.36-0.91; P=.019). CONCLUSION: Prenatal detection of 22q11.2 deletion syndrome was associated with improved delivery management and less cardiac and noncardiac morbidity, but not mortality, compared with postnatal detection.

Noninvasive prenatal screening (NIPS) for fetal chromosome abnormalities in a general-risk population: An evidence-based clinical guideline of the American College of Medical Genetics and Genomics (ACMG).

PURPOSE: This workgroup aimed to develop an evidence-based clinical practice guideline for the use of noninvasive prenatal screening (NIPS) for pregnant individuals at general risk for fetal trisomy 21, trisomy 18, or trisomy 13 and to evaluate the utility of NIPS for other chromosomal disorders. METHODS: The NIPS Evidence-Based Guideline Work Group (n = 7) relied on the results from the recent American College of Medical Genetics and Genomics (ACMG) systematic review to form the evidentiary basis of this guideline. Workgroup members used the Grading of Recommendations Assessment, Development, and Evaluation Evidence to Decision framework to draft recommendations. The guideline underwent extensive internal and external peer review with a public comment period before approval by the ACMG Board of Directors. RESULTS: Evidence consistently demonstrated improved accuracy of NIPS compared with traditional screening methods for trisomies 21, 18, and 13 in singleton and twin gestations. Identification of rare autosomal trisomies and other microdeletion syndromes with NIPS is an emerging area of interest. CONCLUSION: ACMG strongly recommends NIPS over traditional screening methods for all pregnant patients with singleton and twin gestations for fetal trisomies 21, 18, and 13 and strongly recommends NIPS be offered to patients to screen for fetal sex chromosome aneuploidy.

Prenatal detection and evaluation of differences of sex development: A qualitative interview study of parental perspectives and unmet needs.

OBJECTIVES: Prenatal diagnoses of differences of sex development (DSD) are increasing due to availability of cell-free DNA screening (cell-free DNA screening (cfDNA)). This study explores first-hand experiences of parents whose children had prenatal findings of DSD. METHODS: Eligible parents were identified through chart review at a pediatric center and interviewed about their prenatal evaluation, decision making, informational sources, and support systems. Interviews were coded using a combined inductive and deductive thematic analysis. Parents also completed quantitative measures of decisional regret. RESULTS: Seventeen parents (13 mothers; 4 fathers) of 13 children (with 7 DSD diagnoses) were recruited. Four children had discordance between sex predicted by cfDNA versus prenatal ultrasound, and 2 had non-binary appearing (atypical) genitalia on prenatal ultrasound. Of these 6, 3 were not offered additional prenatal testing or counseling. Most parents described tension between obtaining support through disclosure of their child's diagnosis and preserving their child's autonomy/privacy, highlighting the need for mental health support. CONCLUSION: This is the first study to gather qualitative data from parents whose children had prenatal findings of DSD. We identified multiple targets for intervention to improve care for patients with DSD across the lifespan, including improvements in clinician education, pre- and post-test counseling, and patient education materials.

Labour induction for termination of pregnancy with severe fetal anomalies after 24 weeks' gestation: a case series and systematic review of the literature.

PURPOSE: Under some circumstances, individuals choose to undergo pregnancy termination for foetal anomalies in the second half of pregnancy. This report provides objective information on the clinical management of such cases and a systematic review of the literature on labour induction outcomes for third-trimester abortion using mifepristone-misoprostol. MATERIALS AND METHODS: The study is a case series describing outcomes for labour induction abortion for foetal anomalies, at gestational age 24 weeks and beyond. A systematic review was performed, searching PubMed, Embase, and Cochrane databases. Two independent authors reviewed and quality assessed the data from the articles. RESULTS: During a two-year period, 15 patients met inclusion criteria. Fourteen patients received mifepristone and misoprostol, and one received oxytocin. All delivered vaginally. Thirteen patients delivered within 24 hours of the first misoprostol dose, and half delivered within 12 hours. The average interval from misoprostol initiation to foetal expulsion was 15.5 hours in our series. The systematic review identified nine articles for inclusion, all retrospective studies. Labour induction protocols for mifepristone-misoprostol, reporting of gestational age, and key comparisons varied greatly. CONCLUSIONS: The case series illustrates successful termination of pregnancy primarily using combined mifepristone-misoprostol. Certainty of current evidence is low, based on the GRADE framework. Future research is necessary on third-trimester outcomes with mifepristone-misoprostol.

Screening for autosomal recessive and X-linked conditions during pregnancy and preconception: a practice resource of the American College of Medical Genetics and Genomics (ACMG).

Carrier screening began 50 years ago with screening for conditions that have a high prevalence in defined racial/ethnic groups (e.g., Tay-Sachs disease in the Ashkenazi Jewish population; sickle cell disease in Black individuals). Cystic fibrosis was the first medical condition for which panethnic screening was recommended, followed by spinal muscular atrophy. Next-generation sequencing allows low cost and high throughput identification of sequence variants across many genes simultaneously. Since the phrase "expanded carrier screening" is nonspecific, there is a need to define carrier screening processes in a way that will allow equitable opportunity for patients to learn their reproductive risks using next-generation sequencing technology. An improved understanding of this risk allows patients to make informed reproductive decisions. Reproductive decision making is the established metric for clinical utility of population-based carrier screening. Furthermore, standardization of the screening approach will facilitate testing consistency. This practice resource reviews the current status of carrier screening, provides answers to some of the emerging questions, and recommends a consistent and equitable approach for offering carrier screening to all individuals during pregnancy or preconception.

Pregnant Women's Perspectives on Expanded Carrier Screening.

Expanded carrier screening (ECS) is a relatively new carrier screening option that assesses many conditions simultaneously, as opposed to traditional ethnicity-based carrier screening for a limited number of conditions. This study aimed to explore pregnant women's perspectives on ECS, including reasons for electing or declining and anxiety associated with this decision-making. A total of 80 pregnant women were surveyed from Northwestern Medicine's Clinical Genetics Division after presenting for aneuploidy screening. Of the 80 participants, 40 elected and 40 declined ECS. Trends regarding reasons for electing or declining ECS include ethnicity, desire for genetic risk information, lack of family history, perceived likelihood of being a carrier, and perceived impact on reproductive decisions. Individuals who declined ECS seemed to prefer ethnicity-based carrier screening and believed that ECS would increase their anxiety, whereas individuals who elected ECS seemed to prefer more screening and tended to believe that ECS would reduce their anxiety. These findings provide insight on decision-making with regard to ECS and can help guide interactions that genetic counselors and other healthcare providers have with patients, including assisting patients in the decision-making process.

Role of the 3-Vessel and Trachea View in Antenatal Detection of Tetralogy of Fallot.

Prenatal diagnosis of tetralogy of Fallot remains less frequent compared to other major congenital heart defects. In this study, we examined how often the 3-vessel and trachea view was abnormal in a large series of prenatally diagnosed cases of tetralogy of Fallot. In addition, we compared its sensitivity to that of the traditional outflow tract views for detection of tetralogy of Fallot. We found that both views were abnormal in all fetuses with tetralogy of Fallot, showing reversed aortic-to-pulmonary valve and aortic arch isthmus-to-ductus arteriosus ratios in the outflow tract and 3-vessel and trachea views, respectively. However, as a single measured marker, the enlarged aortic arch isthmus on the 3-vessel and trachea view appears to be the most sensitive for tetralogy of Fallot.

Socioeconomic disparities in diagnostic testing after positive aneuploidy screening.

OBJECTIVE: The objective of this study was to investigate the association between type of health insurance (Medicaid vs. private) and uptake of diagnostic testing for fetal aneuploidy after a positive screening test result. METHODS: We performed a retrospective cohort study of pregnant women who underwent aneuploidy screening in the first and/or second trimesters of pregnancy and received positive results. The characteristics of and outcomes for women with Medicaid were compared with those of women with private insurance in both univariable and multivariable analyses. RESULTS: In this study, 75 women with Medicaid and 75 with private insurance were analyzed. Those with Medicaid were younger (33.8 vs. 36.9 years, p < 0.01), and more likely to be of non-white race/ethnicity (88 vs. 27%, p < 0.01), unmarried (65 vs. 19%, p < 0.01), non-English speaking (12 vs. 0%, p < 0.01), and multiparous (76 vs. 59%, p = 0.02). They also were less likely to undergo diagnostic testing after a positive aneuploidy screen (35 vs. 57%, p < 0.01). In multivariable analysis, those with Medicaid remained significantly less likely to undergo diagnostic testing (odds ratio, 0.26; 95% confidence interval, 0.09-0.80). CONCLUSION: Women with Medicaid are less likely than women with private insurance to undergo diagnostic testing after positive screening for aneuploidy. These results emphasize the potential importance of improved counseling for low-income women.

MRI Surveillance and Breast Cancer Mortality in Women With BRCA1 and BRCA2 Sequence Variations.

Importance: Magnetic resonance imaging (MRI) surveillance is offered to women with a pathogenic variant in the BRCA1 or BRCA2 gene who face a high lifetime risk of breast cancer. Surveillance with MRI is effective in downstaging breast cancers, but the association of MRI surveillance with mortality risk has not been well defined. Objective: To compare breast cancer mortality rates in women with a BRCA1 or BRCA2 sequence variation who entered an MRI surveillance program with those who did not. Design, Setting, and Participants: Women with a BRCA1 or BRCA2 sequence variation were identified from 59 participating centers in 11 countries. Participants completed a baseline questionnaire between 1995 and 2015 and a follow-up questionnaire every 2 years to document screening histories, incident cancers, and vital status. Women who had breast cancer, a screening MRI examination, or bilateral mastectomy prior to enrollment were excluded. Participants were followed up from age 30 years (or the date of the baseline questionnaire, whichever was later) until age 75 years, the last follow-up, or death from breast cancer. Data were analyzed from January 1 to July 31, 2023. Exposures: Entrance into an MRI surveillance program. Main Outcomes and Measures: Cox proportional hazards modeling was used to estimate the hazard ratios (HRs) and 95% CIs for breast cancer mortality associated with MRI surveillance compared with no MRI surveillance using a time-dependent analysis. Results: A total of 2488 women (mean [range] age at study entry 41.2 [30-69] years), with a sequence variation in the BRCA1 (n = 2004) or BRCA2 (n = 484) genes were included in the analysis. Of these participants, 1756 (70.6%) had at least 1 screening MRI examination and 732 women (29.4%) did not. After a mean follow-up of 9.2 years, 344 women (13.8%) developed breast cancer and 35 women (1.4%) died of breast cancer. The age-adjusted HRs for breast cancer mortality associated with entering an MRI surveillance program were 0.20 (95% CI, 0.10-0.43; P < .001) for women with BRCA1 sequence variations and 0.87 (95% CI, 0.10-17.25; P = .93) for women with BRCA2 sequence variations. Conclusion and Relevance: Results of this cohort study suggest that among women with a BRCA1 sequence variation, MRI surveillance was associated with a significant reduction in breast cancer mortality compared with no MRI surveillance. Further studies of women with BRCA2 sequence variations are needed to ascertain these women obtain the same benefits associated with MRI surveillance.

3-D ultrasound of the fetal ear and fetal autosomal trisomies: a pilot study of a new screening protocol.

OBJECTIVE: We hypothesize that the rotation of the ear in fetuses with common autosomal trisomies will be markedly different from euploid fetuses and amenable to detection by 3-D ultrasound in the render mode. METHODS: Study participants (10 weeks 4 days through 19 weeks 0 days) underwent a 3-D rendering of the fetal face and ear along with other biometric measurements prior to invasive testing. RESULTS: Of the 348 patients who underwent chorionic villi sampling (CVS) (n = 208) or amniocentesis (n = 140), 18 were diagnosed with trisomy 21, 4 with trisomy 18, and 1 with trisomy 13. Mean gestational age was 12 weeks 6 days (range: 10 weeks 6 days to 19 weeks 0 days). Ear angles were obtained in all cases; the time to obtain this angle ranged from 5 to 25 min. Thirty-two fetuses were found to have an abnormal ear angle with 23 of the 32 characterized by one of the aforementioned trisomies. CONCLUSIONS: These findings support the potential of this technique to provide valuable information in the identification of an increased-risk population. Prospective studies are needed to confirm the value of this screening modality as well as to assess its facility and ability to be incorporated into routine obstetrical practice.

Three-dimensional fast acquisition with sonographically based volume computer-aided analysis for imaging of the fetal heart at 18 to 22 weeks' gestation.

OBJECTIVE: The purpose of this study was to determine how frequently cardiac images derived from 3-dimensional (3D) volume sets, acquired by fast acquisition and evaluated with sonographically based volume computer-aided analysis (sonoVCAD), were satisfactory for prenatal screening at 18 to 22 weeks' gestation. METHODS: A prospective study of 100 women with singleton pregnancies was undertaken. Three fast acquisition 3D volume sets were obtained from each patient. Four reviewers independently evaluated the 4-chamber and 5 extracted VCAD views. Factors contributing to unsatisfactory screening were also evaluated. RESULTS: The frequency with which adequate views for cardiac screening could be obtained varied widely; some single views, such as that of the stomach, were well seen frequently, whereas others, such as the ductal arch, were well seen significantly less frequently (P < .05). A satisfactory screening examination, defined as a visualized 4-chamber, left ventricular outflow tract, right ventricular outflow tract, and axial stomach view, was obtained for 43% to 65% of patients (dependent on reviewer). Logistic regression revealed that obesity (odds ratio, 3.0; 95% confidence interval, 1.7-5.0) and a fetus with the spine toward the maternal abdomen (odds ratio, 1.7; 95% confidence interval, 1.1-2.5) were independently associated with an unsatisfactory screening examination CONCLUSIONS: Three-dimensional fast acquisition volumes evaluated with sonoVCAD did not allow a satisfactory fetal cardiac screening examination to be obtained a high percentage of the time in a general obstetric population during the second trimester. Certain patient factors, such as body habitus and fetal position, are associated with unsatisfactory 3D imaging.

Founder Fukutin mutation causes Walker-Warburg syndrome in four Ashkenazi Jewish families.

OBJECTIVE: Walker-Warburg syndrome (WWS) is a genetically heterogeneous congenital muscular dystrophy caused by abnormal glycosylation of alpha-dystroglycan (alpha-DG) that is associated with brain malformations and eye anomalies. The Fukutin (FKTN) gene, which causes autosomal recessively inherited WWS is most often associated with Fukuyama congenital muscular dystrophy in Japan. We describe the clinical features of four nonconsanguinous Ashkenazi Jewish families with WWS and identify the underlying genetic basis for WWS. METHOD: We screened for mutations in POMGnT1, POMT1, POMT2, and FKTN, genes causing WWS, by dideoxy sequence analysis. RESULTS: We identified an identical homozygous c.1167insA mutation in the FKTN gene on a common haplotype in all four families and identified 2/299 (0.7%) carriers for the c.1167insA mutation among normal American Ashkenazi Jewish adults. CONCLUSION: These data suggest that the c.1167insA FKTN mutation described by us is a founder mutation that can be used to target diagnostic testing and carrier screening in the Ashkenazi Jewish population.

Expanded carrier screening: what the reproductive endocrinologist needs to know.

Expanded carrier screening refers to identification of carriers of single-gene disorders outside of traditional screening guidelines. New genetic testing technologies allow for such screening at costs that are comparable to single-gene testing. There is a high degree of variability among genetic testing laboratories as to the inclusion of different disorders, some of which have mild or unpredictable phenotypes. This review discusses the pros and cons of using expanded carrier screening in the preconceptional patient and reviews guidelines currently endorsed by professional organizations.