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Genes Mar 2021In 1959, 63 years after the death of John Langdon Down, Jérôme Lejeune discovered trisomy 21 as the genetic reason for Down syndrome. Screening for Down syndrome has... (Review)
Review
In 1959, 63 years after the death of John Langdon Down, Jérôme Lejeune discovered trisomy 21 as the genetic reason for Down syndrome. Screening for Down syndrome has been applied since the 1960s by using maternal age as the risk parameter. Since then, several advances have been made. First trimester screening, combining maternal age, maternal serum parameters and ultrasound findings, emerged in the 1990s with a detection rate (DR) of around 90-95% and a false positive rate (FPR) of around 5%, also looking for trisomy 13 and 18. With the development of high-resolution ultrasound, around 50% of fetal anomalies are now detected in the first trimester. Non-invasive prenatal testing (NIPT) for trisomy 21, 13 and 18 is a highly efficient screening method and has been applied as a first-line or a contingent screening approach all over the world since 2012, in some countries without a systematic screening program. Concomitant with the rise in technology, the possibility of screening for other genetic conditions by analysis of cfDNA, such as sex chromosome anomalies (SCAs), rare autosomal anomalies (RATs) and microdeletions and duplications, is offered by different providers to an often not preselected population of pregnant women. Most of the research in the field is done by commercial providers, and some of the tests are on the market without validated data on test performance. This raises difficulties in the counseling process and makes it nearly impossible to obtain informed consent. In parallel with the advent of new screening technologies, an expansion of diagnostic methods has begun to be applied after invasive procedures. The karyotype has been the gold standard for decades. Chromosomal microarrays (CMAs) able to detect deletions and duplications on a submicroscopic level have replaced the conventional karyotyping in many countries. Sequencing methods such as whole exome sequencing (WES) and whole genome sequencing (WGS) tremendously amplify the diagnostic yield in fetuses with ultrasound anomalies.
Topics: Chromosome Disorders; Female; Genetic Testing; Humans; Microarray Analysis; Pregnancy; Prenatal Diagnosis
PubMed: 33805390
DOI: 10.3390/genes12040501 -
Genome Medicine Oct 2022Exome sequencing (ES) is becoming more widely available in prenatal diagnosis. However, data on its clinical utility and integration into clinical management remain...
BACKGROUND
Exome sequencing (ES) is becoming more widely available in prenatal diagnosis. However, data on its clinical utility and integration into clinical management remain limited in practice. Herein, we report our experience implementing prenatal ES (pES) in a large cohort of fetuses with anomalies detected by ultrasonography using a hospital-based in-house multidisciplinary team (MDT) facilitated by a three-step genotype-driven followed by phenotype-driven analysis framework.
METHODS
We performed pES in 1618 fetal cases with positive ultrasound findings but negative for karyotyping and chromosome microarray analysis between January 2014 and October 2021, including both retrospective (n=565) and prospective (n=1053) cohorts. The diagnostic efficiency and its correlation to organ systems involved, phenotypic spectrum, and the clinical impacts of pES results on pregnancy outcomes were analyzed.
RESULTS
A genotype-driven followed by phenotype-driven three-step approach was carried out in all trio pES. Step 1, a genotype-driven analysis resulted in a diagnostic rate of 11.6% (187/1618). Step 2, a phenotype-driven comprehensive analysis yielded additional diagnostic findings for another 28 cases (1.7%; 28/1618). In the final step 3, data reanalyses based on new phenotypes and/or clinical requests found molecular diagnosis in 14 additional cases (0.9%; 14/1618). Altogether, 229 fetal cases (14.2%) received a molecular diagnosis, with a higher positive rate in the retrospective than the prospective cohort (17.3% vs. 12.4%, p<0.01). The diagnostic rates were highest in fetuses with skeletal anomalies (30.4%) and multiple organ involvements (25.9%), and lowest in fetuses with chest anomalies (0%). In addition, incidental and secondary findings with childhood-onset disorders were detected in 11 (0.7%) cases. Furthermore, we described the prenatal phenotypes for the first time for 27 gene-associated conditions (20.0%, 27/135) upon a systematic analysis of the diagnosed cases and expanded the phenotype spectrum for 26 (19.3%) genes where limited fetal phenotypic information was available. In the prospective cohort, the combined prenatal ultrasound and pES results had significantly impacted the clinical decisions (61.5%, 648/1053).
CONCLUSIONS
The genotype-driven approach could identify about 81.7% positive cases (11.6% of the total cohort) with the initial limited fetal phenotype information considered. The following two steps of phenotype-driven analysis and data reanalyses helped us find the causative variants in an additional 2.6% of the entire cohort (18.3% of all positive findings). Our extensive phenotype analysis on a large number of molecularly confirmed prenatal cases had greatly enriched our current knowledge on fetal phenotype-genotype correlation, which may guide more focused prenatal ultrasound in the future. This is by far the largest pES cohort study that combines a robust trio sequence data analysis, systematic phenotype-genotype correlation, and well-established MDT in a single prenatal clinical setting. This work underlines the value of pES as an essential component in prenatal diagnosis in guiding medical management and parental decision making.
Topics: Pregnancy; Female; Humans; Exome; Retrospective Studies; Cohort Studies; Prospective Studies; Ultrasonography, Prenatal; Prenatal Diagnosis; Fetus
PubMed: 36307859
DOI: 10.1186/s13073-022-01130-x -
Taiwanese Journal of Obstetrics &... Sep 2020Fetal sex discordance is an entity that is becoming more frequent due to the expansion of the cfDNA for prenatal diagnosis. Its incidence can be estimated in 1/1500-2000... (Review)
Review
Fetal sex discordance is an entity that is becoming more frequent due to the expansion of the cfDNA for prenatal diagnosis. Its incidence can be estimated in 1/1500-2000 pregnancies, a frequency as high as that of some common chromosomopathies. The causes of this phenomenon are multiple and diverse, ranging from laboratory errors to important pathologies such as disorders of sexual differentiation. The management of a case of fetal sex discordance must be structured, starting with the review of the clinical history and the tests performed, and may require the performance of invasive tests to reach a diagnosis. Prevention through adequate pretest counseling and ultrasound confirmation can help to reduce its incidence.
Topics: Cell-Free Nucleic Acids; Disorders of Sex Development; Female; Humans; Maternal Serum Screening Tests; Pregnancy; Sex Characteristics; Sex Determination Analysis; Ultrasonography, Prenatal
PubMed: 32917312
DOI: 10.1016/j.tjog.2020.07.004 -
Prenatal Diagnosis Jun 2022About 3% of newborns show malformations, with about 20% of the affected having genetic causes. Clarification of genetic diseases in postnatal diagnostics was...
OBJECTIVE
About 3% of newborns show malformations, with about 20% of the affected having genetic causes. Clarification of genetic diseases in postnatal diagnostics was significantly improved with high-throughput sequencing, in particular through whole exome sequencing covering all protein-coding regions. Here, we aim to extend the use of this technology to prenatal diagnostics.
METHOD
Between 07/2018 and 10/2020, 500 pregnancies with fetal ultrasound abnormalities were analyzed after genetic counseling as part of prenatal diagnostics using WES of the fetus and parents.
RESULTS
Molecular genetic findings could explain ultrasound abnormalities in 38% of affected fetuses. In 47% of these, disease-causing de novo variants were found. Pathogenic variants in genes with autosomal recessive or X-linked inheritance were detected in more than one-third (70/189 = 37%). The latter are associated with increased probability of recurrence, making their detection important for further pregnancies. Average time from sample receipt to report was 12 days in the recent cases.
CONCLUSION
Trio exome sequencing is a useful addition to prenatal diagnostics due to its high diagnostic yield and short processing time (comparable to chromosome analysis). It covers a wide spectrum of genetic changes. Comprehensive interdisciplinary counseling before and after diagnostics is indispensable.
Topics: Exome; Female; Fetus; Humans; Infant, Newborn; Pregnancy; Prenatal Diagnosis; Ultrasonography, Prenatal; Exome Sequencing
PubMed: 34958143
DOI: 10.1002/pd.6081 -
Prenatal Diagnosis May 2022We conducted a systematic review and meta-analysis to determine the diagnostic yield of exome sequencing (ES) for prenatal diagnosis of fetal structural anomalies, where... (Meta-Analysis)
Meta-Analysis
OBJECTIVES
We conducted a systematic review and meta-analysis to determine the diagnostic yield of exome sequencing (ES) for prenatal diagnosis of fetal structural anomalies, where karyotype/chromosomal microarray (CMA) is normal.
METHODS
Following electronic searches of four databases, we included studies with ≥10 structurally abnormal fetuses undergoing ES or whole genome sequencing. The incremental diagnostic yield of ES over CMA/karyotype was calculated and pooled in a meta-analysis. Sub-group analyses investigated effects of case selection and fetal phenotype on diagnostic yield.
RESULTS
We identified 72 reports from 66 studies, representing 4350 fetuses. The pooled incremental yield of ES was 31% (95% confidence interval (CI) 26%-36%, p < 0.0001). Diagnostic yield was significantly higher for cases pre-selected for likelihood of monogenic aetiology compared to unselected cases (42% vs. 15%, p < 0.0001). Diagnostic yield differed significantly between phenotypic sub-groups, ranging from 53% (95% CI 42%-63%, p < 0.0001) for isolated skeletal abnormalities, to 2% (95% CI 0%-5%, p = 0.04) for isolated increased nuchal translucency.
CONCLUSION
Prenatal ES provides a diagnosis in an additional 31% of structurally abnormal fetuses when CMA/karyotype is non-diagnostic. The expected diagnostic yield depends on the body system(s) affected and can be optimised by pre-selection of cases following multi-disciplinary review to determine that a monogenic cause is likely.
Topics: Exome; Female; Humans; Pregnancy; Pregnancy Trimester, First; Prenatal Diagnosis; Ultrasonography, Prenatal; Exome Sequencing
PubMed: 35170059
DOI: 10.1002/pd.6115 -
Genes May 2024In many countries, some form of genetic screening is offered to all or part of the population, either in the form of well-organized screening programs or in a less... (Review)
Review
In many countries, some form of genetic screening is offered to all or part of the population, either in the form of well-organized screening programs or in a less formalized way. Screening can be offered at different phases of life, such as preconception, prenatal, neonatal and later in life. Screening should only be offered if the advantages outweigh the disadvantages. Technical innovations in testing and treatment are driving changes in the field of prenatal and neonatal screening, where many jurisdictions have organized population-based screening programs. As a result, a greater number and wider range of conditions are being added to the programs, which can benefit couples' reproductive autonomy (preconception and prenatal screening) and improve early diagnosis to prevent irreversible health damage in children (neonatal screening) and in adults (cancer and cascade screening). While many developments in screening are technology-driven, citizens may also express a demand for innovation in screening, as was the case with non-invasive prenatal testing. Relatively new emerging issues for genetic screening, especially if testing is performed using DNA sequencing, relate to organization, data storage and interpretation, benefit-harm ratio and distributive justice, information provision and follow-up, all connected to acceptability in current healthcare systems.
Topics: Humans; Genetic Testing; Neonatal Screening; Prenatal Diagnosis; Female; Pregnancy; Infant, Newborn
PubMed: 38790210
DOI: 10.3390/genes15050581 -
Journal of Perinatal Medicine Jul 2023
Topics: Pregnancy; Female; Humans; Stem Cells; Parturition; Prenatal Diagnosis
PubMed: 36958941
DOI: 10.1515/jpm-2022-0583 -
Ultrasound in Obstetrics & Gynecology :... Jun 2023
Topics: Pregnancy; Female; Humans; Prenatal Diagnosis; Prenatal Care; Heart; Heart Diseases; Ultrasonography, Prenatal
PubMed: 37267096
DOI: 10.1002/uog.26224 -
Taiwanese Journal of Obstetrics &... Jan 2021Abdominal lymphatic malformations (LM) are rare congenital malformations of the lymphatic system, representing only 2% of all LM in newborns. They may arise from... (Review)
Review
Abdominal lymphatic malformations (LM) are rare congenital malformations of the lymphatic system, representing only 2% of all LM in newborns. They may arise from intra-abdominal solid organs (such as the liver, pancreas, kidneys, spleen, adrenal glands, and gastrointestinal tract), mesentery, omentum, and retroperitoneum. Mesenteric LM are the most commonly seen, with retroperitoneal LM being the second most common. Fetal abdominal LM could be associated with karyotypic or other abnormalities, including skin edema, hydrops fetalis, and polyhydramnios, and prenatal diagnosis and perinatal counseling for these LM are important. Prenatal ultrasound (US) and magnetic resonance imaging (MRI) have led to an increased diagnosis of abdominal LM and improved monitoring and intervention postnatally. This article provides an overview of fetal abdominal LM, including the prenatal diagnoses, differential diagnoses, comprehensive illustrations of the imaging findings, treatments, and fetal outcomes.
Topics: Abdomen; Diagnosis, Differential; Female; Humans; Lymphatic Abnormalities; Magnetic Resonance Imaging; Pregnancy; Prenatal Diagnosis; Ultrasonography, Prenatal
PubMed: 33494985
DOI: 10.1016/j.tjog.2020.11.003 -
Neurology India 2021Fetal ventriculomegaly (VM) refers to the abnormal enlargement of one or more ventricles of the brain in-utero. The enlargement may or may not be related to ventricular... (Review)
Review
Fetal ventriculomegaly (VM) refers to the abnormal enlargement of one or more ventricles of the brain in-utero. The enlargement may or may not be related to ventricular obstruction and increased intracranial pressure; therefore, the term "hydrocephalus" is not used. VM is diagnosed usually in the mid-trimester when the atrial diameter (AD) of the lateral ventricle is more than 10 mm on one or both sides. A thorough workup is then required to identify the cause as the etiology is diverse. Fetal magnetic resonance imaging (MRI) may yield additional information. Serial ultrasound follow-up would be required to assess its progression with advancing gestation. The prognosis and long-term outcomes greatly depend upon the etiology, the severity at diagnosis, progression, and associations. This article reviews the definitions, diagnosis, and workup of fetal VM, discusses follow-up protocols and prognosis, and examines the role of fetal therapy, including fetoscopic surgery in its prenatal management.
Topics: Female; Humans; Hydrocephalus; Magnetic Resonance Imaging; Nervous System Malformations; Pregnancy; Prenatal Diagnosis; Ultrasonography, Prenatal
PubMed: 35102981
DOI: 10.4103/0028-3886.332280