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.

Unique risk factors for unplanned preterm delivery in the uterus transplant recipient.

STUDY QUESTION: Do characteristics of the lower uterine segment and cervix modify the risk of preterm delivery in uterus transplant (UTx) recipients? SUMMARY ANSWER: The cervical length showed little association with preterm delivery, however, cervical inflammation deserves further exploration as a cause of preterm delivery. WHAT IS KNOWN ALREADY: UTx recipients do not have the risk factors normally used to stratify pregnancies that would benefit from cervical length assessment. In addition, unique factors related to absent tissues, a different blood supply, inflammatory processes of rejection, cervical biopsies, and a different microbiome challenge the normal progressive remodeling of the cervix and thus cervical competence. STUDY DESIGN, SIZE, DURATION: This is a subanalysis of a clinical trial of 20 women undergoing uterus transplantation at Baylor University Medical Center from 2016 to 2020, in addition to two women who received transplantation outside of a research protocol at our institution through September 2022. In this report, the first 16 UTx recipients that achieved live birth are included. PARTICIPANTS/MATERIALS, SETTING, METHODS: The focus of this study was 20 pregnancies that reached the second trimester in 16 women following UTx. We analyzed recipient, transplant, and donor factors to determine if characteristics were associated with delivery outcome. We compared obstetrical outcomes, including planned versus unplanned delivery, by factors such as number of superior venous anastomoses, warm ischemia and cold ischemia times, donor factors including cesarean sections, cervical biopsy results, and cervical ultrasound results. MAIN RESULTS AND THE ROLE OF CHANCE: Planned term deliveries occurred in 44% (8/18) of live births. Of the preterm births, 30% (3/10) were planned and 70% (7/10) were unplanned. Unplanned deliveries occurred in women with spontaneous preterm labor, severe rejection, subchorionic hematoma, and placenta previa. Cervical length in UTx recipients averaged 33.5 mm at 24 weeks and 31.5 mm at 28 weeks, comparable to values from the general population. No relationship was seen between delivery outcome and number of veins used, ischemic time, or number of previous cesarean sections. LIMITATIONS, REASONS FOR CAUTION: The study's small size allows limited conclusions. The obstetric history of all donors was limited to mode of delivery. WIDER IMPLICATIONS OF THE FINDINGS: Cervical length measurements in the UTx population are not expected to deviate from those with a native uterus. While cervical length surveillance remains important, attention must be paid to the results of cervical biopsies which are obtained to monitor rejection. Inflammatory processes seem most predictive of preterm delivery. STUDY FUNDING/COMPETING INTEREST(S): No funding was provided for this study. The authors report no conflicts of interest. TRIAL REGISTRATION NUMBER: NCT02656550.

Neonatal Outcomes after Uterus Transplantation: Dallas Uterus Transplant Study.

OBJECTIVE: Limited data are available on the outcome of infants born after uterus transplantation. Our aim was to describe the hospital course and laboratory findings in the first 2 months of life of the 12 infants born in the Dallas UtErus Transplant Study (DUETS). STUDY DESIGN: Based on the trial protocol, information about infants was collected in a prospective fashion, including infant demographics, hospital course, and laboratory values. RESULTS: Twelve infants were delivered, all by cesarean section, from 11 mothers who had undergone uterus transplantation (one mother had two pregnancies and delivered two babies). All pregnancies were singleton. The mothers received immunosuppressive therapy, and one had a rejection episode that was detected during pregnancy. The rejection episode resolved after steroid treatment. The infants had a median gestational age of 366/7 weeks (range: 306/7-380/7 weeks) and median birth weight of 2,920 g (range: 1,770-3,470 g). The lowest Apgar's score at 5 minutes was 8. All infants were appropriate size for gestational age. Two infants presented with bandemia but negative blood cultures. At 2 months of age, all infants achieved the developmental and behavioral milestones outlined by the American Academy of Pediatrics. CONCLUSION: The 12 infants born from mothers with uterus transplants had a neonatal course that reflected the gestational age at delivery. No baby was born with an identified malformation or organ dysfunction. Longer follow-up and a larger number of infants are needed to confirm these observations. KEY POINTS: · Normal fetal development after uterus transplantation.. · No baby was born with malformations or showed any organ dysfunction.. · At 2 months, all infants achieved appropriate developmental and behavioral milestones..

Doppler Flow Indices and Prediction of Embryo Transfer Success and Pregnancy Outcome in Uterus Transplant Recipients.

OBJECTIVE: Doppler velocimetry of the uterine and umbilical arteries is used to predict preeclampsia and monitor fetal outcomes. There have been no reports of Doppler velocimetry indices in pregnancies conceived after uterus transplantation, which differ from traditional pregnancies because of different uterine vascular inflow and outflow and exposure to immunosuppressive agents. We sought to examine whether Doppler indices can be used to predict embryo transfer success after uterus transplantation and whether Doppler indices across pregnancy predict fetal growth restriction. STUDY DESIGN: This was a single-center cohort observational study of 14 uterus transplant recipients who underwent embryo transfer. Of these, 12 women successfully delivered 14 babies. Five Doppler investigations were performed within the cohort: (1) prepregnancy; (2) uterine artery assessment across pregnancy; (3) umbilical artery assessment across pregnancy; (4) successive pregnancies; and (5) fetal growth. RESULTS: Prepregnancy uterine artery Doppler indices did not correlate with successful implantation after embryo transfer. Uterine artery Doppler indices in uterus transplant recipients decreased across pregnancy as described in pregnancies without uterus transplantation. The umbilical artery systolic/diastolic velocity ratio was lower at all weeks of gestation after uterus transplantation compared with values described in pregnancies without uterus transplantation. In those women who delivered two successive babies after uterus transplant, umbilical artery Doppler indices were significantly lower during the second pregnancy. There was always forward flow throughout diastole in the umbilical arteries, and no babies experienced fetal growth restriction. CONCLUSION: In our study, uterus transplantation was not associated with abnormal blood flow indices in either the uterine or umbilical arteries. Although Doppler indices were not predictive of embryo transfer success, they supported the expectation that pregnancies after uterus transplantation at our center result in normally grown babies. KEY POINTS: · Uterus transplantation is not associated with abnormal blood flow indices.. · Prepregnancy uterine artery Doppler indices did not correlate with successful embryo implantation.. · Doppler assessment supports the expectation of normal placentation, fetal growth, and healthy live births after uterus transplantation..

Carrier frequency of autosomal recessive genetic conditions in diverse populations: Lessons learned from the genome aggregation database.

An equitable approach by the American College of Medical Genetics and Genomics (ACMG) has recently recommended carrier screening for genes associated with moderate to severe autosomal recessive conditions with a carrier frequency of ≥1/200 in the Genome Aggregation Database exomes (gnomADv2.0.2). We analyzed carrier frequencies in gnomADv3.1.1 genomes representing diverse populations. ClinVar data on 35 996 pathogenic/likely pathogenic variants in 419 genes were used to estimate the gnomAD frequency of heterozygous carriers. We found that ninety-two genes had a carrier frequency of ≥1/200, of which 63 were shared between v3.1.1 and v2.0.2 and 29 were new in v3.1.1. Addition of new populations (Amish, Finnish and Middle Eastern) increased the number of new genes with a carrier frequency of ≥1/200 to 71. Changes in carrier frequencies were attributed to new gnomAD populations, different sample sizes, new ClinVar data, and technical differences between exomes and genomes. This study highlights the dynamic changes in carrier frequencies due to new datasets from diverse populations and provides updated carrier frequencies based on the combined data from 184 352 genomes and exomes in gnomAD. We recommend a periodic review for inclusion of new population data to update carrier screening panels in the future.

Genetic Screening and Teratogenic Exposures: Considerations in Caring for the Uterus Transplant Patient.

Counseling the uterus transplant patient requires an enhanced knowledge of unique genetic challenges that include an understanding of the spectrum of Mayer-Rokitansky-Küster-Hauser syndrome. Patients should understand their options for genetic screening and testing including preimplantation genetic testing for aneuploidy, genetic screening, and diagnostic testing. This patient population is potentially at risk for fetal anomalies due to the increased susceptibility to infections, such as cytomegalovirus. There are management strategies to minimize this risk. The risk of teratogenicity from mycophenolate is eliminated by a washout period before embryo transfer.

Antepartum Care of the Uterus Transplant Patient: The Experience of 3 Successful US Centers.

We offer consensus recommendations for the antepartum management of the uterus transplant pregnancy based on our experience at 3 US centers. Patient access to accurate information is important to manage expectations and make informed decisions. Unique aspects of medical management include monitoring tacrolimus levels and performing cervical biopsies for rejection. Low-dose aspirin for preeclampsia is routinely used. Vigilant screening for gestational diabetes and preeclampsia allows for the prompt diagnosis and treatment of these common complications. We aim to deliver patients at 37 to 38 weeks by cesarean section. Shared decision making dominates whether to consider future pregnancies and timing of hysterectomy.

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.

Clinical pregnancy rates and experience with in vitro fertilization after uterus transplantation: Dallas Uterus Transplant Study.

BACKGROUND: The clinical pregnancy rates among patients with uterus transplantation have been reported by only a limited number of centers, and those centers have not used preimplantation genetic testing for aneuploidy in their protocol. OBJECTIVE: This study examined clinical pregnancy rates among women with absolute uterine-factor infertility undergoing in vitro fertilization using good-quality, expanded-blastocyst-stage, euploid embryos after uterus transplantation. STUDY DESIGN: This cohort observational study involved 20 women who underwent uterus transplantation over 3 years. Notably, 14 of these patients had successful transplants and were followed prospectively for a median of 14.1 months (range, 11-34.8 months). In vitro fertilization was performed before subjects underwent uterus transplantation, and good-quality expanded-blastocyst-stage euploid embryos were obtained and frozen for future embryo transfer. Interventions consisted of in vitro fertilization, preimplantation genetic testing for aneuploidy, uterus transplantation, and frozen embryo transfer. RESULTS: All 14 subjects with successful transplants underwent single embryo transfer of a warmed, good-quality, euploid, expanded blastocyst and had at least 1 documented clinical pregnancy within the uterus. In 71.4%, the first embryo transfer resulted in clinical pregnancy. The median time from successful uterus transplantation to first embryo transfer was 4.5 months; from successful uterus transplantation to first clinical pregnancy, 7.3 months; and from successful uterus transplantation to first live birth, 14.1 months. A total of 13 live births have occurred in 12 subjects. CONCLUSION: Women with absolute uterine-factor infertility who have surgically successful uterus transplantation and in vitro fertilization using preimplantation genetic testing for aneuploidy can achieve high clinical pregnancy rates. We have reduced the time interval from uterus transplantation to embryo transfer by at least 50% and the interval from uterus transplantation to clinical pregnancy by >6 months compared with previous studies. We believe our approach may shorten the time from transplant to clinical pregnancy and therefore decrease patient exposure to immunosuppressant therapies.

The Evolution of Transplantation From Saving Lives to Fertility Treatment: DUETS (Dallas UtErus Transplant Study).

OBJECTIVE: We report the results of the first 20 uterus transplants performed in our institution. SUMMARY BACKGROUND DATA: Uterus transplantation (UTx) aims at giving women affected by absolute uterine-factor infertility the possibility of carrying their own pregnancy. UTx has evolved from experimental to an established surgical procedure. METHODS: The Dallas Uterus Transplant Study (DUETS) program started in 2016. The uterus was transplanted in orthotopic position with vascular anastomoses to the external iliac vessels and removed when 1 or 2 live births were achieved. Immunosuppression lasted only for the duration of the uterus graft. RESULTS: Twenty women, median age 29.7 years, enrolled in the study, with 10 in phase 1 and 10 in phase 2. All but 2 recipients had a congenital absence of the uterus. Eighteen recipients received uteri from living donors and 2 from deceased donors. In phase 1, 50% of recipients had a technically successful uterus transplant, compared to 90% in phase 2. Four recipients with a technical success in phase 1 have delivered 1 or 2 babies, and the fifth recipient with a technical success is >30 weeks pregnant. In phase 2, 2 recipients have delivered healthy babies and 5 are pregnant. CONCLUSIONS: UTx is a unique type of transplant; whose only true success is a healthy child birth. Based on results presented here, involving refinement of the surgical technique and donor selection process, UTx is now an established solution for absolute uterine-factor infertility.

Laboratory screening and diagnosis of open neural tube defects, 2019 revision: a technical standard of the American College of Medical Genetics and Genomics (ACMG).

Open neural tube defects (ONTDs) include open spina bifida (OSB) and anencephaly. These defects are caused by incomplete closure of the neural tube at about 4 weeks of pregnancy. Levels of early second-trimester maternal serum (ms) alpha-fetoprotein (AFP) are sufficiently elevated in affected pregnancies to be used as a population-based screening test. The basic screening methodology was described in the late 1970s and screening programs were active a few years later. By identifying pregnancies with the highest msAFP levels, about 80% of OSB and 95% of anencephaly can be identified as early as 16 weeks gestation. The interpretation of msAFP levels is complicated by the need to consider multiple factors such as gestational age, maternal weight, maternal race, multiple gestations, and more. Testing for AFP and acetylcholinesterase in amniotic fluid and/or identification of the lesion by targeted ultrasound is considered diagnostic of ONTD. When a diagnosis is made, options include termination, surgery after delivery, or in utero surgery, depending on factors such as location and size of the defect, and the presence of any additional anomalies. Screening for ONTD should be performed as part of a comprehensive program linking primary obstetrical care providers, laboratorians, and high-risk clinicians.

CFTR variant testing: a technical standard of the American College of Medical Genetics and Genomics (ACMG).

Pathogenic variants in the CFTR gene are causative of classic cystic fibrosis (CF) as well as some nonclassic CF phenotypes. In 2001, CF became the first target of pan-ethnic universal carrier screening by molecular methods. The American College of Medical Genetics and Genomics (ACMG) recommended a core panel of 23 disease-causing variants as the minimal set to be included in pan-ethnic carrier screening of individuals with no family history of the disease, and these variants were usually assessed using targeted methods. The original recommendation also left open the option for laboratories to offer expanded CFTR variant panels; however, at the time, expanded CFTR variant panels were met with some controversy on the basis of the available technologies and the limited phenotypic knowledge of rare variants. Both of those aspects have now evolved, prompting this update of the ACMG technical standards for CFTR variant testing.

Estimating yields of prenatal carrier screening and implications for design of expanded carrier screening panels.

PURPOSE: Prenatal genetic carrier screening can identify parents at risk of having a child affected by a recessive condition. However, the conditions/genes most appropriate for screening remain a matter of debate. Estimates of carrier rates across genes are needed to guide construction of carrier screening panels. METHOD: We leveraged an exome sequencing database (n = 123,136) to estimate carrier rates across six major ancestries for 415 genes associated with severe recessive conditions. RESULTS: We found that 32.6% (East Asian) to 62.9% (Ashkenazi Jewish) of individuals are variant carriers in at least one of the 415 genes. For couples, screening all 415 genes would identify 0.17-2.52% of couples as being at risk for having a child affected by one of these conditions. Screening just the 40 genes with carrier rate >1.0% would identify more than 76% of these at-risk couples. An ancestry-specific panel designed to capture genes with carrier rates >1.0% would include 5 to 28 genes, while a comparable panethnic panel would include 40 genes. CONCLUSION: Our work guides the design of carrier screening panels and provides data to assist in counseling prospective parents. Our results highlight a high cumulative carrier rate across genes, underscoring the need for careful selection of genes for screening.

Adherence of cell-free DNA noninvasive prenatal screens to ACMG recommendations.

PURPOSE: Noninvasive prenatal screening (NIPS) for fetal aneuploidy via cell-free DNA has been commercially available in the United States since 2011. In 2016, the American College of Medical Genetics and Genomics (ACMG) issued a position statement with specific recommendations for testing laboratories. We sought to evaluate adherence to these recommendations. METHODS: We focused on commercial laboratories performing NIPS testing in the United States as of 1 January 2018. Sample laboratory reports and other materials were scored for compliance with ACMG recommendations. Variables scored for common and sex chromosome aneuploidy detection included detection rate, specificity, positive and negative predictive value, and fetal fraction. Labs that performed analysis of copy-number variants and results for aneuploidies other than those commonly reported were identified. Available patient education materials were similarly evaluated. RESULTS: Nine of 10 companies reported fetal fraction in their reports, and 8 of 10 did not offer screening for autosomal aneuploidies beyond trisomy 13, 18, and 21. There was inconsistency in the application and reporting of other measures recommended by ACMG. CONCLUSIONS: Laboratories varied in the degree to which they met ACMG position statement recommendations. No company adhered to all laboratory guidance.

Photoplethysmography and Heart Rate Variability for the Diagnosis of Preeclampsia.

BACKGROUND: The goal of this study was to determine a set of timing, shape, and statistical features available through noninvasive monitoring of maternal electrocardiogram and photoplethysmography that identifies preeclamptic patients. METHODS: Pregnant women admitted to Labor and Delivery were monitored with pulse oximetry and electrocardiogram for 30 minutes. Photoplethysmogram features and heart rate variability were extracted from each data set and applied to a sequential feature selection algorithm to discriminate women with preeclampsia with severe features, from normotensive and hypertensive controls. The classification boundary was chosen to minimize the expected misclassification cost. The prior probabilities of the misclassification costs were assumed to be equal. RESULTS: Thirty-seven patients with clinically diagnosed preeclampsia with severe features were compared with 43 normotensive controls; all were in early labor or beginning induction. Six variables were used in the final model. The area under the receiver operating characteristic curve was 0.907 (standard error [SE] = 0.004) (sensitivity 78.2% [SE = 0.3%], specificity 89.9% [SE = 0.1%]) with a positive predictive value of 0.883 (SE = 0.001). Twenty-eight subjects with chronic or gestational hypertension were compared with the same preeclampsia group, generating a model with 5 features with an area under the curve of 0.795 (SE = 0.007; sensitivity 79.0% [SE = 0.2%], specificity 68.7% [SE = 0.4%]), and a positive predictive value of 0.799 (SE = 0.002). CONCLUSIONS: Vascular parameters, as assessed noninvasively by photoplethysmography and heart rate variability, may have a role in screening women suspected of having preeclampsia, particularly in areas with limited resources.

Noninvasive prenatal screening by next-generation sequencing.

Noninvasive prenatal screening (NIPS) has emerged as a highly accurate method of screening for fetal Down syndrome, with a detection rate and specificity approaching 100%. Challenging the widespread use of this technology are cost and the paradigm shift in counseling that accompanies any emerging technology. The expense of the test is expected to decrease with increased utilization, and well beyond the current NIPS technology, its components (fetal genome measurements, sequencing technology, and bioinformatics) will be utilized alone or in combinations to interrogate the fetal genome. The end goal is simple: to offer patients information early in pregnancy about fetal genomes without incurring procedural risks. This will allow patients an opportunity to make informed reproductive and pregnancy management decisions based on precise fetal genomic information.

Futuristic Look at Genetic and Birth Defect Diagnoses and Treatments.

One aim of prenatal care is to provide information to prospective parents. The information provided encompasses prenatal care, intrapartum and postpartum care. Learning the genetic constitution of the parents pre-conception or the ongoing pregnancy allows parents to make decisions and set expectations. Offering screening and diagnostic testing has been the main in satisfying the desire for prenatal genetic information. With rapid advances in genomics and genome sequencing, screening during an ongoing pregnancy may become obsolete. Preconception risk will be determined by whole exome sequencing and chromosomal microarray of prospective parents and a number of approaches to alter pregnancy outcome can be considered when genome variations are identified. Therapeutic approaches include mitochondrial transfer and gene editing, two technologies that are in early stages, but showing promise as tools to alter outcomes.