Agenesis of the Ductus Venosus and Its Association With Genetic Abnormalities.

OBJECTIVE: To investigate the association of agenesis of the ductus venosus (ADV) with genetic abnormalities using genetic studies-Chromosomal Microarray Analysis (CMA) and Exome Sequencing (ES). DESIGN: Retrospective study of all fetuses diagnosed with ADV between January 2013 and December 2022 in a tertiary center. RESULTS: ADV was diagnosed in 33 fetuses. The diagnosis was made at a mean gestational age of 21.2 ± 8.4 weeks. Conventional karyotype was applied in a single fetus (3.0%), CMA was applied in 21 fetuses (66.7%), and five fetuses (22.8%) were additionally tested with ES. ADV was isolated in eight fetuses (24%), whereas in 25 (76%) it was associated with abnormal ultrasound findings, including increased nuchal translucency (NT), intrauterine growth restriction (IUGR) and variable structural malformations, mostly cardiac (42%) followed by central nervous system (CNS) and skeletal malformations (24%). Genetic abnormalities were found in six fetuses out of 22 investigated (27%), of which 3 were detected by ES, 3 by CMA and 1 by conventional karyotype. A higher incidence of genetic aberrations was evident among ADVs associated with abnormal ultrasound findings. Genetic abnormalities were indicative of Prader Willi/Angelman syndrome, Noonan syndrome, CASK related disorder, 16q24.3 microdeletion syndrome and Trisomy 21. CONCLUSION: ADV associated with abnormal ultrasound findings is commonly correlated with genetic abnormalities and consequently unfavorable pregnancy outcomes. Our study emphasizes the value of genetic studies chiefly among cases associated with abnormal ultrasound findings, enabling early diagnosis of fetal pathologies associated with ADV, and providing better parental counseling.

Exploring the human genomic landscape: patterns of common homozygosity regions in a large middle eastern cohort.

Regions of Homozygosity (ROH) typically reflect normal demographic history of a human population, but may also relate to cryptic consanguinity, and, additionally, have been associated with specific medical conditions. The objective of this study was to investigate the location, size, and prevalence of common ROH segments in a Middle Eastern cohort. This retrospective study included 13 483 samples collected from all Chromosomal Microarray analyses (CMA) performed using Single Nucleotide Polymorphism (SNP) arrays at the genetic clinical laboratory of Rabin Medical Center between 2017-2023 (primary data set). An additional replication cohort including 100 842 samples from another SNP array platform, obtained from Maccabi Health Organization, was analyzed. Common ROH locations were defined as those ROH locations involving 1% or more of the samples. A total of 66 710 ROH segments, involving 13 035 samples (96.7%) were identified in the primary data set. Of the 4069 cytogenetic ROH locations, 68 were identified as common. The prevalence of non-common ROH was relatively high in affected individuals, and for acrocentric chromosomes, chromosomes associated with common trisomies, and non-imprinted chromosomes. In addition, differences in common ROH locations were observed between the primary and the replication cohorts. Our findings highlight the need for population-specific guidelines in determining ROH reporting cutoffs, considering factors such as population-specific prevalence and testing platform differences. Future research with larger, varied cohorts is essential to advance understanding of ROH's associations with medical conditions and to improve clinical practices accordingly.

Prenatal diagnosis of the recurrent 1q21.1 microdeletions in fetuses with ultrasound anomalies and review of the literature.

Objective: The recurrent 1q21.1 microdeletion syndrome is an autosomal dominant disorder and is characterized by dysmorphic facial features, microcephaly, developmental delay, and congenital defects. However, most studies on the distal deletions in the 1q21.1 region were diagnosed postnatally. This study aimed to provide a better understanding of the ultrasound and molecular findings of fetuses with recurrent 1q21.1 microdeletions in prenatal diagnosis. Methods: In this retrospective study, we reported 21 cases with the recurrent 1q21.1 microdeletion syndrome diagnosed at our prenatal diagnostic center from January 2016 to January 2023. The clinical data were reviewed for these cases, including the maternal demographics, indications for invasive testing, ultrasound findings, CMA results, and pregnancy outcomes. Results: In the study, a total of 21 cases with recurrent 1q21.1 microdeletions were diagnosed prenatally by CMA. Fifteen cases were described with ultrasound indications, and the most common findings are as follows: increased nuchal translucency (NT) (26.7%), intrauterine growth retardation (IUGR) (26.7%), congenital heart defects (CHD) (20%), and congenital anomalies of the kidney and urinary tract (CAKUT) (13.3%). All the cases with the distal 1q21.1 deletions contain the common minimal region (located between BP3 and BP4) and eight OMIM genes. Parental studies to determine the inheritance of the deletion were performed for eight cases, and half of the cases were inherited from one of the parents. Pregnancy outcomes were available for nine cases; eight (88.9%) pregnancies were determined to be terminated and one (11.1%) was full-term delivery. Conclusion: To our knowledge, this is the largest study to find that fetuses with recurrent 1q21.1 microdeletions were closely associated with increased NT, CHD, IUGR, and CAKUT. In addition, ours is the first study to report that cerebral ventriculomegaly might be associated with recurrent 1q21.1 microdeletions. More comprehensive studies are needed for a better understanding of the prenatal phenotype-genotype relationship of the recurrent 1q21.1 microdeletion syndrome in future.

Prenatal diagnosis of fetuses with 15q11.2 BP1-BP2 microdeletion in the Chinese population: a seven-year single-center retrospective study.

BACKGROUND: The 15q11.2 BP1-BP2 microdeletion syndrome is associated with developmental delays, language impairments, neurobehavioral disorders, and psychiatric complications. The aim of the present study was to provide prenatal and postnatal clinical data for 16 additional fetuses diagnosed with the 15q11.2 BP1-BP2 microdeletion syndrome in the Chinese population. METHODS: A total of 5,789 pregnancy women that underwent amniocentesis were enrolled in the present study. Both karyotype analysis and chromosomal microarray analysis (CMA) were conducted on these subjects to detect chromosomal abnormalities and copy number variants (CNVs). Whole exome sequencing (WES) was performed to investigate sequence variants in subjects with clinical abnormalities after birth. RESULTS: Sixteen fetuses with 15q11.2 BP1-BP2 microdeletion were identified in the present study, with a detection rate of 0.28% (16/5,789). The 15q11.2 BP1-BP2 microdeletion fragments ranged from 311.8 kb to 849.7 kb, encompassing the NIPA1, NIPA2, CYFIP1, and TUBGCP5 genes. The follow-up results regarding pregnancy outcomes showed that five cases opted for pregnancy termination, while the remaining cases continued with their pregnancies. Subsequent postnatal follow-up indicated that only one case with the 15q11.2 BP1-BP2 microdeletion displayed neurodevelopmental disorders, demonstrating an incomplete penetrance rate of 9.09% (1/11). CONCLUSION: The majority of fetuses with the 15q11.2 microdeletion exhibit typical features during early childhood, indicating a low penetrance and mild impact. Nonetheless, pregnancies involving fetuses with the 15q11.2 microdeletion require thorough prenatal counseling. Additionally, enhanced supervision and extended postnatal monitoring are warranted for those who choose to proceed with their pregnancies.

Clinical and genetic analysis of two phenotypically normal families carrying 4p16.1 microduplications.

OBJECTIVE: To help determine the pathogenicity of 4p16.1 microduplications, we reported two asymptomatic families carrying this variation. CASE REPORT: We present the prenatal diagnosis and genetic analysis of two normal families with 4p16.1 microduplications. CONCLUSION: This paper highlights two families with clinically asymptomatic 4p16.1 microduplications that assisted in determining the pathogenicity of this fragment. The findings can be used as a reference for genetic counseling in cases of similar abnormalities encountered during future prenatal diagnosis.

Prenatal diagnosis of 17q12 copy number variants in fetuses via chromosomal microarray analysis - A retrospective cohort study and literature review.

Purpose: 17q12 copy number variants (CNVs) have variable presentations and incomplete penetrance, challenging prenatal counseling and management. This study aims to investigate the intrauterine phenotype. Methods: We included 48 fetuses diagnosed with 17q12 microdeletion or microduplication by chromosomal microarray analysis. Results: For 17q12 deletion, renal anomalies were found in 35 fetuses (35/37, 94.6 %), with hyperechogenic kidneys (HEK, 28/37, 75.7 %) and multicystic dysplastic kidneys (17/37, 45.9 %) being the most common findings. Duodenal obstruction (DO) was most frequently combined in 17q12 duplication fetuses. In addition, cardiac abnormalities were the first reported prenatal phenotype in 17q12 duplication fetuses. Conclusion: Our study shows that HEK and DO are the most predominant presentations of 17q12 deletion and duplication, respectively, and cardiac structural abnormalities may be associated with the latter. Although 17q12 CNVs have incomplete penetrance and variable expressivity and may be mainly involved in neurodevelopmental disorders, their short-term prognosis appears positive.

Molecular cytogenetic characterization of isolated recurrent 4q35.2 microduplication in Chinese population: a seven-year single-center retrospective study.

BACKGROUND: With the extensive use of chromosomal microarray analysis (CMA), an increasing number of variants of uncertain significance (VOUS) have been detected. The objective of the present study was to elucidate the pathogenicity and clinical variability associated with isolated recurrent 4q35.2 microduplications within the Chinese population. METHODS: The present study involved 14 cases of isolated recurrent 4q35.2 microduplication (including 12 fetuses and 2 cases of pediatric patients) out of 5,188 subjects who sought genetic consultation at our hospital and received CMA detection. WES technology was subsequently utilized to identify additional sequence variants in a patient with multiple clinical anomalies. RESULTS: All 14 cases exhibited isolated recurrent 4q35.2 microduplications spanning a 1.0-Mb region encompassing the ZFP42 gene. Among the 12 fetuses, 11 displayed normal clinical features, while one was born with renal duplication and hydronephrosis. Additionally, in the two pediatric patients, WES was performed for Case 1, who presented with congenital cataracts, severe intellectual disability, and seizures. This patient inherited the 4q35.2 microduplication from his phenotypically normal mother. WES identified a novel NM_000276:c.2042G > T (p.G681V) variant in the OCRL gene, which is associated with Lowe syndrome and may account for the observed phenotypic variability within this family. CONCLUSION: A series of 14 cases with isolated recurrent 4q35.2 microduplications were investigated, highlighting a potential association with increased susceptibility to renal abnormalities. Further, the present findings may expand the mutation spectrum of the OCRL gene associated with Lowe syndrome and provide valuable insights for the genetic etiological diagnosis of patients with unexplained copy number variants.

Prenatal diagnosis in fetal right aortic arch using chromosomal microarray analysis and whole exome sequencing: a Chinese single-center retrospective study.

BACKGROUND: Right aortic arch (RAA) is a common congenital aortic arch abnormality. Fetuses with RAA frequently have good outcomes after birth. However, chromosomal abnormalities and genetic syndromes suggest poor prognosis for these patients. So far the underlying genetic etiology is still not identified in most RAA patients based on traditional genetic techniques and a problem is still debated whether fetuses with isolated RAA should be referred for CMA. Our study aims to investigate the genetic etiology of fetuses with right aortic arch (RAA) by chromosomal microarray analysis (CMA) and whole exome sequencing (WES) and evaluate the efficacy of CMA in fetal isolated RAA. RESULTS: Among these 153 fetuses, 99 (64.7%) with isolated RAA and 54 (35.3%) with non-isolated RAA; 25.5% (39/153) with additional intracardiac anomalies (ICA), and 19.0% (29/153) with extracardiac anomalies (ECA). Tetralogy of Fallot (n = 10) and persistent left superior vena cava (n = 11) are the most common ICA and ECA, respectively. CMA detected 15 clinically significant copy number variations (CNVs) in 14 cases (9.2%); microdeletion of 22q11.21 was the most common pathogenic CNVs (7.8%). The chromosomal abnormalities rate was higher in non-isolated RAA and RAA with ICA groups than in isolated RAA group (16.7% vs. 5.1%; 20% vs. 5.1%, both p < 0.05). From five cases further undergoing WES, a diagnostic variant in MTOR gene (c.7255G > A, de novo) was first reported in prenatal, extending the prenatal manifestation of Smith-Kingsmore syndrome (OMIM: 616638); a clinically relevant variant c.3407A > T in STAG2 was identified, being inherited from the healthy mother. Moreover, the premature birth and termination rates were higher in non-isolated RAA group than in isolated RAA group (11.1% vs. 1.0%; 37.0% vs. 2.0%, both p < 0.01). CONCLUSIONS: We demonstrate that CMA and WES are useful diagnostic tools for fetal RAA, particularly non-isolated RAA, and all fetuses with RAA should be referred for CMA. The data probably aids in prenatal diagnosis and prenatal counseling of fetal RAA.

[Genetic testing in neurological diseases: a practical guide]. / Pruebas genéticas en enfermedades neurológicas: guía práctica.

During the last decades, genomic medicine has made it possible to bring the knowledge of molecular genetics to the field of medical consultation. There are several studies that contribute to the diagnosis, the definition of prognoses, as well as the possibility of providing genetic counseling based on accurate scientific data. Advances in genomic sequencing have promoted the reclassification of entities according to an etiological criterion. Such is the case of epileptic encephalopathies, ataxias, dystonias, among many other neurological conditions. Its implementation requires strategies aimed at achieving the best diagnostic yield. This requires a greater understanding of the molecular bases of each of these practices, as well as their scope. They allow reducing the time until a certain diagnosis is made and the possibility, in some cases, of improving the quality of life of those affected with the use of tailored treatments. The objective of this article was to describe current laboratory studies, their scope and emphasize the algorithms for the study of genetic diseases in general, focusing the attention on those specific to neuropediatrics, in order to promote good practices, avoiding confusion, errors, and unnecessary expenditures of money and shortening the so-called "diagnostic odyssey".

Durante las últimas décadas la medicina genómica ha llevado al ámbito de la consulta médica los conocimientos de la genética molecular. Existe un número de estudios que contribuyen en el diagnóstico, la definición de pronósticos y posibilitan un asesoramiento genético basado en datos científicos certeros. En algunas enfermedades, los avances en la secuenciación genómica, ha promovido la reclasificación de entidades según un criterio etiológico, como las encefalopatías epilépticas, las ataxias, las distonías, entre muchas condiciones médicas. Su implementación requiere, por parte de los médicos, de estrategias tendientes a alcanzar el mejor rédito diagnóstico. Es necesario para ello, una mayor comprensión de las bases moleculares de estas prácticas, así como sus alcances. Permiten reducir los tiempos hasta la concreción de un diagnóstico de certeza y la posibilidad, en algunos casos, de mejorar la calidad de vida de los afectados con la utilización de tratamientos a la medida. El objetivo de este artículo fue describir las técnicas de laboratorio actuales, sus alcances y enfatizar los algoritmos de estudio de las enfermedades genéticas, haciendo hincapié en aquellas propias de la neuropediatría, a fin de propiciar las buenas prácticas, evitando confusiones, errores, erogaciones innecesarias de dinero y acortando la llamada "odisea diagnóstica".

The Genetic Architecture of Congenital Heart Disease in Neonatal Intensive Care Unit Patients-The Experience of University Medical Centre, Ljubljana.

Congenital heart disease (CHD) is the most commonly detected congenital anomaly and affects up to 1% of all live-born neonates. Current guidelines support the use of chromosomal microarray analysis (CMA) and next-generation sequencing (NGS) as diagnostic approaches to identify genetic causes. The aim of our study was to evaluate the diagnostic yield of CMA and NGS in a cohort of neonates with both isolated and syndromic CHD. The present study included 188 infants under 28 days of age with abnormal echocardiography findings hospitalized at the Department of Neonatology, UMC Ljubljana, between January 2014 and December 2023. Phenotypic data were obtained for each infant via retrospective medical chart review. We established the genetic diagnosis of 22 distinct syndromes in 17% (32/188) of neonates. The most frequent genetic diagnoses in diagnosed cases were 22q11.2 microdeletion and CHARGE syndromes, followed by Noonan syndrome and Williams syndrome. In addition, we detected variants of uncertain significance in 4.8% (9/188) of neonates. Timely genetic diagnosis is important for the detection of syndrome-related comorbidities, prognosis, reproductive genetic risks and, when appropriate, genetic testing of other family members.

Perinatal outcomes after a prenatal diagnosis of a fetal copy number variant: a retrospective population-based cohort study.

BACKGROUND: There are no established guidelines for the follow up of infants born after a prenatal diagnosis of a genomic copy number variant (CNV), despite their increased risk of developmental issues. The aims of this study were (i) to determine the perinatal outcomes of fetuses diagnosed with and without a CNV, and (ii) to establish a population-based paediatric cohort for long term developmental follow up. METHODS: An Australian state-wide research database was screened for pregnant individuals who had a prenatal chromosomal microarray (CMA) between 2013-2019 inclusive. Following linkage to laboratory records and clinical referrer details, hospital records were manually reviewed for study eligibility. Eligible participants were mother-child pairs where the pregnancy resulted in a livebirth, the mother was able to provide informed consent in English (did not require a translator) and the mother was the primary caregiver for the child at hospital discharge after birth. Research invitations were sent by registered post at an average of six years after the prenatal diagnostic test. Statistical analysis was performed in Stata17. RESULTS: Of 1832 prenatal records examined, 1364 (74.5%) mother-child pairs were eligible for recruitment into the follow up cohort. Of the 468 ineligible, 282 (60.3%) had 'no live pregnancy outcome' (209 terminations of pregnancy (TOP) and 73 miscarriages, stillbirths, and infant deaths), 157 (33.5%) required a translator, and 29 (6.2%) were excluded for other reasons. TOP rates varied by the type of fetal CNV detected: 49.3% (109/221) for pathogenic CNVs, 18.2% (58/319) for variants of uncertain significance and 3.3% (42/1292) where no clinically significant CNV was reported on CMA. Almost 77% of invitation letters were successfully delivered (1047/1364), and the subsequent participation rate in the follow up cohort was 19.2% (201/1047). CONCLUSIONS: This study provides Australia's first population-based data on perinatal outcomes following prenatal diagnostic testing with CMA. The relatively high rates of pregnancy loss for those with a prenatal diagnosis of a CNV presented a challenge for establishing a paediatric cohort to examine long term outcomes. Recruiting a mother-child cohort via prenatal ascertainment is a complex and resource-intensive process, but an important step in understanding the impact of a CNV diagnosis in pregnancy and beyond. TRIAL REGISTRATION: ACTRN12620000446965p; Registered on April 6, 2020.

Prenatal chromosomal microarray analysis in a large Chinese cohort of fetuses with congenital heart defects: a single center study.

BACKGROUND AND OBJECTIVES: Congenital heart defect (CHD) is one of the most common birth defects. The aim of this cohort study was to evaluate the prevalence of chromosomal abnormalities and the clinical utility of chromosomal microarray analysis (CMA) in fetuses with different types of CHD, aiming to assist genetic counseling and clinical decision-making. METHODS: In this study, 642 fetuses with CHD were enrolled from a single center over a six-year period (2017-2022). Both conventional karyotyping and CMA were performed simultaneously on these fetuses. RESULTS: The diagnostic yield of CMA in fetuses with CHD in our study was 15.3% (98/642). Our findings revealed a significant increase in the diagnostic yield of CMA compared to karyotyping in fetuses with CHD. Among CHD subgroups, the diagnostic yields were high in complex CHD (34.9%), conotruncal defects (28.6%), right ventricular outflow tract obstructive defects (RVOTO) (25.9%), atrioventricular septal defects (AVSD) (25.0%) and left ventricular outflow tract obstructive defects (LVOTO) (24.1%), while those in other CHD (10.6%) and septal defects (10.9%) were relatively low. The overall detection rate of clinically significant chromosomal abnormalities was significantly higher in the non-isolated CHD group compared to the isolated CHD group (33.1% vs. 9.9%, P < 0.0001). Interestingly, numerical chromosomal abnormalities were more likely to occur in the non-isolated CHD group than in the isolated CHD group (20.3% vs. 2.0%, P < 0.0001). The rate of termination of pregnancy (TOP)/Still birth in the non-isolated CHD group was significantly higher than that in the isolated CHD group (40.5% vs. 20.6%, P < 0.0001). Compared to the isolated CHD group, the detection rate of clinically significant chromosomal abnormalities was significantly higher in the group of CHD with soft markers (35.6% vs. 9.9%, P < 0.0001) and in the group of CHD with additional structural anomalies (36.1% vs. 9.9%, P < 0.0001). CONCLUSIONS: CMA is a reliable and high-resolution technique that should be recommended as the front-line test for prenatal diagnosis of fetuses with CHD. The prevalence of chromosomal abnormalities varies greatly among different subgroups of CHD, and special attention should be given to prenatal non-isolated cases of CHD, especially those accompanied by additional structural anomalies or soft markers.

Prenatal diagnosis of dicentric chromosome X mosaicism: a case report and review.

A dicentric chromosome is an abnormal chromosome with two centromeres on the same chromosome. It has been reported that dicentric chromosomes are specific biomarkers of radiation exposure, but dicentric chromosomes are rarely identified in newborns with multiple congenital anomalies. At 16 weeks of gestation, a 39-year-old pregnant woman (gravida 2, para 1) was referred to the prenatal diagnosis center for genetic counseling. The fetal ultrasonography indicated multiple anomalies. Subsequently, amniocentesis was performed, and the G-banding karyotype analysis showed a rare type of mosaicism. The C-banding karyotype analysis indicated a pseudo-dicentric chromosome X [psu dic (X; 18) (p11.2; p11.2)]. A single-nucleotide polymorphism array (SNP array) revealed three pathogenic copy number variations (CNVs). After genetic counseling, the parents chose to terminate this pregnancy. This study provides new evidence for a better understanding of the diagnosis of dicentric chromosomes and emphasizes on the importance of genetic counseling.

Prenatal Diagnosed Agenesis of the Corpus Callosum: Identifying the Underlying Genetic Etiologies.

OBJECTIVE: To assess the genetic etiologies underlying agenesis of the corpus callosum (ACC) and its pregnancy outcomes in the era of next-generation sequencing. METHODS: A retrospective analysis was conducted on prospectively collected prenatal ACC cases in which amniocentesis was performed between January 2016 and December 2022. ACC was divided into non-isolated and isolated according to the presence or absence of ultrasound abnormalities. Chromosomal microarray analysis (CMA), karyotyping and exome sequencing (ES) were performed after genetic counseling. Pregnancy outcomes were assessed by pediatric neurosurgeons and were followed up by telephone through their parents. RESULTS: Sixty-eight fetuses with ACC were enrolled in this study. CMA detected eight cases with pathogenic copy number variants (CNVs) and all were non-isolated ACC, with a detection rate of 11.8% (8/68). Among the CMA abnormalities, the majority (6/8) were detectable by karyotyping. ES was performed in 26 cases with normal CMA, revealing pathogenic or likely pathogenic gene variations in 12 cases (46.2%, 12/26), involving L1CMA, SMARCB1, PPP2R1A, ARID1B, USP34, CDC42, NFIA and DCC genes. The detection rates of ES in isolated and non-isolated ACC were 40% (6/15) and 54.5% (6/11), respectively. After excluding cases where pregnancy was terminated (56 cases), there were 12 live births, ranging in age from 15 months to 7 years. Of these, 91.7% (11 out of 12) demonstrated normal neurodevelopmental outcomes. Specifically, all five cases with isolated ACC and negative ES results exhibited normal neurodevelopment. The remaining six cases with favorable outcomes were all isolated ACC, among which ES identified variants of DCC and USP34 gene in one each case. The other four cases were CMA-negative and declined ES. CONCLUSIONS: We highlight the efficacy of prenatal ES in determining the genetic etiology of ACC, whether isolated or not. Favorable neurodevelopmental outcomes were observed when ACC was isolated and with normal ES results.

Regions of Homozygocity size patterns among diverse ethnic groups in Israel: Toward tailored diagnostic reporting thresholds.

Long contiguous stretches of homozygosity or regions of homozygosity (ROH) are frequently detected via microarray and sequencing technologies. However, consensus on the establishment of specific size cutoffs for reporting ROH remains elusive. This study aims to assess the Total ROH Percentages (TRPS) and size of ROH segments across different ethnic origins, exploring potential disparities and proposing tailored diagnostic thresholds. This retrospective study included 13,035 microarray analyses conducted between 2017 to 2023. ROH segments on autosomal chromosomes were retrieved, and samples lacking ROH segments were excluded. The cohort was categorized based on reported ethnic origins, and TRPS and ROH segment size were analyzed for each origin. Distinct TRPS values were noted among different ethnic groups, ranging from median 0.36% in Ethiopian Jewish cohort and up to 6.42% in the Bedouin population. Wide range of 99th percentiles of ROH segment size for various origins was noted, ranging from 10.6 to 51.5 Mb. A significant correlation between ROH segment sizes and TRPS was noted in each origin. Statistically significant differences in ROH segment sizes were noted between the Jewish and the Israeli Arab/Druze origins in TRPS from 1% to 9.99%, whereas extremities of low (0.11%-0.99%) and high (over 10%) TRPS yielded no significant differences. In conclusion, as fixed absolute size thresholds may overlook pathogenic segments in certain populations while generating excessive reports in others, tailored approaches to define ROH reporting thresholds can be considered to facilitate the accuracy and clinical relevance of genomic analyses.

Chromosomal Microarray Analysis in Fetuses with Ultrasound Abnormalities.

Objective: To explore and evaluate the value of chromosomal microarray analysis (CMA) in prenatal diagnosis of fetuses with ultrasound abnormalities. Methods: A retrospective analysis was performed on 370 fetuses with ultrasound abnormalities received invasive prenatal diagnosis at Meizhou People's Hospital from October 2022 to December 2023. Fetal specimens were analyzed by CMA, and the detection rates of aneuploidy and pathogenic (P)/likely pathogenic (LP) copy number variations (CNVs) in ultrasound structural abnormalities (malformations of fetal anatomy) and non-structural abnormalities (abnormalities of fetal nonanatomical structure) were analyzed. Results: There were 114 (30.8%) cases with isolated ultrasound structural abnormalities, 226 (61.1%) cases with isolated non-structural abnormalities (182 isolated ultrasound soft markers abnormalities, 30 isolated fetal growth restriction (FGR), and 8 isolated abnormalities of amniotic fluid volume), and 30 (8.1%) cases with both structural and non-structural abnormalities. The overall detection rate of aneuploidy and P/LP CNVs in isolated ultrasonic structural abnormalities was 5.3%, among which cardiovascular system abnormalities were the highest. In addition, the largest number of fetuses with non-structural abnormalities was nuchal translucency (NT) thickening (n = 81), followed by ventriculomegaly (n = 29), and nasal bone dysplasia (n = 24). The detection rate of chromosomal abnormalities of fetuses with abnormal ultrasound soft markers was 9.9%, and the detection rate in single abnormal ultrasound soft marker, and multiple ultrasound soft markers abnormalities was 9.7% (16/165) and 11.8% (2/17), respectively. Moreover, the detection rate of chromosomal abnormalities of fetuses with FGR and structural abnormalities combined with non-structural abnormalities was 6.7% (2/30), and 13.3% (4/30), respectively. Conclusion: The incidence of chromosomal abnormalities (aneuploidy and P/LP CNVs) varies among different fetal ultrasound abnormalities.

Prenatal Diagnosis of Fetuses with 4q35 Deletion: Case Series and Review of the Literature.

INTRODUCTION: 4q35 deletion is a rare chromosomal syndrome with a wide range of phenotypes, which can be challenging to detect through prenatal ultrasound. This study aimed to summarize the fetal phenotypes of patients with 4q35 deletion. CASE PRESENTATION: The study included four fetuses with 4q35 deletion, with detailed records of prenatal ultrasound and genetic testing results. These cases included following phenotypes, fetal growth restriction (FGR) (2/4), cystic hygroma (2/4), single umbilical artery (1/4), and fused kidney (1/4). One case was terminated, while the other three were born and showed no obvious abnormalities at the 1-year follow-up. Previous reports have described the fetal phenotype of 4q35 deletion in 6 patients from five families, with prenatal phenotypes including FGR (2/6), cardiac structural abnormalities (1/6), brain ventriculomegaly (1/6), oligohydramnios (1/6), and multicystic dysplastic kidneys (1/6). CONCLUSION: Overall, the phenotypes of fetuses with 4q35 deletion are diverse, with FGR potentially being a significant phenotype in these cases.

Association of prenatal Cleft Lip and Palate ultrasound abnormalities with copy number variants at a single Chinese tertiary center.

BACKGROUD: A systematic analysis was conducted to investigate the molecular etiology of fetal cleft lip and/or palate (CL/P) and the association between various types of CL/P and copy number variations (CNVs), as well as their impact on birth outcomes. METHODS: In this retrospective study conducted between January 2016 and July 2022, a cohort of pregnancies diagnosed with fetal CL/P was enrolled and comprehensive clinical data for all cases were extracted from our medical record database, including demographic data about the pregnancies, ultrasound findings, results of Chromosomal microarray (CMA), as well as relevant pregnant and perinatal outcomes. RESULTS: Among the 358 cases, 32 clinically significant variants in 29 (8.1%) fetuses with CL/P were detected by CMA. In 338 singleton pregnancies, the diagnostic yield of CMA in the context of CL/P fetuses was determined to be 7.7% (26/338). CP cases exhibited a relatively higher prevalence of pathogenic/likely pathogenic CNVs at a rate of 25% (3/12), followed by CLP cases at 8.0% (23/288). Notably, the CL group did not demonstrate any pathogenic/likely pathogenic CNV findings among the examined cases (0/38). The diagnostic rate of clinically significant variants was notably higher in the non-isolated CL/P group than in the isolated CL/P group (11/33, 33.3% vs. 15/305, 4.9%, p < 0.001). Within the remaining 20 twin pregnancies, three clinically significant variants (15%) were observed. CONCLUSIONS: This study provides powerful evidence supporting the efficacy of CMA as a valuable tool for facilitating the prenatal genetic diagnosis of fetal CL/P. The presence of CP and CLP in fetal cases demonstrated a relatively higher incidence of pathogenic/likely pathogenic CNVs. Moreover, when these cases were accompanied by additional ultrasound abnormalities, the likelihood of identifying diagnostic CNVs significantly increased. Conversely, cases of CL alone might not be associated with positive CNVs. The present data may significantly enhance prenatal diagnosis accuracy and facilitate informed genetic counseling for cases of fetal CL/P.

Chromosomal abnormalities detected by chromosomal microarray analysis and pregnancy outcomes of 4211 fetuses with high-risk prenatal indications.

With the gradual liberalization of the three-child policy and the development of assisted reproductive technology in China, the number of women with high-risk pregnancies is gradually increasing. In this study, 4211 fetuses who underwent chromosomal microarray analysis (CMA) with high-risk prenatal indications were analysed. The results showed that the overall prenatal detection rate of CMA was 11.4% (480/4211), with detection rates of 5.82% (245/4211) for abnormal chromosome numbers and 5.58% (235/4211) for copy number variants. Additionally, the detection rates of clinically significant copy number variants were 3.78% (159/4211) and 1.8% (76/4211) for variants of uncertain significance. The detection rates of fetal chromosomal abnormalities were 6.42% (30/467) for pregnant women with advanced maternal age (AMA), 6.01% (50/832) for high-risk maternal serum screening (MSS) results, 39.09% (224/573) with abnormal non-invasive prenatal testing (NIPT) results, 9.21% (127/1379) with abnormal ultrasound results, and 5.1% (49/960) for other indications. Follow-up results were available for 4211 patients, including 3677 (3677/4211, 87.32%) whose infants were normal after birth, 462 (462/4211, 10.97%) who terminated their pregnancy, 51 (51/4211, 1.21%) whose infants were abnormal after birth, and 21 (21/4211, 0.50%) who refused follow-up. The results of this study demonstrate significant variation in the diagnostic rate of chromosomal microarray analysis across different indications, providing valuable guidance for clinicians to assess the applicability of CMA technology in prenatal diagnosis.

Prenatal diagnosis and genetic study of 22q11.2 microduplication in Chinese fetuses: A series of 31 cases and literature review.

BACKGROUND: Patients with 22q11.2 microduplication syndrome exhibit a high degree of phenotypic heterogeneity and incomplete penetrance, making prenatal diagnosis challenging due to phenotypic variability. This report aims to raise awareness among prenatal diagnostic practitioners regarding the variant's complexity, providing a basis for prenatal genetic counseling. METHODS: Family and clinical data of 31 fetuses with 22q11.2 microduplications confirmed by chromosomal microarray between June 2017 and June 2023 were considered. RESULTS: Primary prenatal ultrasound features of affected fetuses include variable cardiac and cardiovascular anomalies, increased nuchal translucency (≥3 mm), renal abnormalities, and polyhydramnios. More than half of fetuses considered showed no intrauterine manifestations; therefore, prenatal diagnostic indicators were primarily advanced maternal age or high-risk Down syndrome screening. Most fetuses had microduplications in proximal or central 22q11.2 regions, with only three cases with distal microduplications. Among parents of fetuses considered, 87% (27/31) continued the pregnancy. During follow-up, 19 cases remained clinically asymptomatic. CONCLUSION: Nonspecific 22q11.2 microduplication features in fetuses and its mild postnatal disease presentation highlight the need to cautiously approach prenatal diagnosis and pregnancy decision-making. Increased clinical efforts should be made regarding providing parents with specialized genetic counseling, long-term follow-up, and fetal risk information.