Management and Outcomes of Hepatoblastoma in Patients With Trisomy 18: A Systematic Review and Pooled Analysis of 70 Patients.

INTRODUCTION: Predicted 1-year survival of children with trisomy 18 (T18) has increased to 59.3%. We aimed to systematically review the characteristics, management, and outcomes of children with T18 and hepatoblastoma. METHODS: A systematic literature review of the PubMed, Embase, Scopus, Web of Science, and Cochrane Library databases was performed according to the PRISMA 2020 statement (end-of-search date: 03/03/2024). RESULTS: Fifty studies reporting on 70 patients were included. The median age at diagnosis was 11.5 months, 85.9% were female (n = 55/64), and 15.0% had mosaic T18 (n = 6/40). Diagnosis was made during symptom evaluation (most commonly hepatomegaly or abdominal mass) in 45.5% (n = 15/33), incidentally in 24.2% (n = 8/33), during surveillance with abdominal ultrasound in 18.2% (n = 6/33), and at autopsy in 12.1% (n = 4/33). The median tumor size was 6.4 cm, 33.3% had multiple tumors (n = 14/42), and metastasis was present in one patient (3.8%; n = 1/26). Neoadjuvant chemotherapy was administered in 42.6% (n = 26/61) and adjuvant chemotherapy in 31.6% (n = 18/57). Surgical treatment was performed in 64.2% (n = 43/67). Of the patients not diagnosed on autopsy, overall mortality was 35.5% (n = 22/62) over a median follow-up of 11.0 months. Among the 26 deceased patients (including those diagnosed on autopsy), the most common causes of death were cardiopulmonary disease (38.5%, n = 10/26) and tumor progression (30.8%, n = 8/26). CONCLUSIONS: T18 does not preclude resection with curative intent for hepatoblastoma. Combination of surgery and chemotherapy should be considered in children on an individualized basis depending on tumor characteristics and underlying cardiopulmonary comorbidities. Locoregional modalities may have a role in the setting of severe comorbidities. LEVEL OF EVIDENCE: Level IV evidence.

Performance analysis of non-invasive prenatal testing for trisomy 13, 18, and 21: A large-scale retrospective study (2018-2021).

Background: Non-invasive prenatal tests (NIPT) are used to screen for trisomy 21, 18, and 13. This study investigated NIPT performance and the clinical significance of its results. Methods: Pregnant women (n = 282,911) participating in a free NIPT (April 2018-December 2021) were screened for common trisomies, and the results were retrospectively analyzed. NIPT performance was evaluated by its positive predictive value (PPV), sensitivity, and specificity. Results were analyzed using number, percentage, and chi-squared/t-test analyses. Results: After NIPT screening, patients with common trisomies (n = 746) included 457 with T21, 160 with T18, and 129 with T13. Seven false negative cases were identified. High PPV (86.81 %, 56.81 %, 18.18 %), sensitivity (99.25 %, 98.33 %, 100.00 %), and specificity (99.98 %, 99.98 %, 99.97 %) values were detected for trisomy 21, 18, and 13, respectively. The PPVs of common trisomies were significantly different between pregnant women older than 35 (85.53 %, 136/159) and those aged 35 or younger (58.90 %, 311/528) (χ2 = 125.02, P = 2.20e-16). As the NIPT uptake increased from 2018 to 2021, live-born birth defect incidence decreased. Conclusion: NIPT performed well in screening for T21, T18, and T13. Our discoveries offer an important and useful guideline in laboratory and clinical genetic counseling.

Impact of definitive surgery for esophageal atresia on long-term outcomes in patients with trisomy 18.

This study investigates the long-term outcomes of palliative and definitive surgeries for esophageal atresia (EA) in patients with trisomy 18 syndrome. A retrospective study included 25 cases undergoing EA surgery at our center between 2008 and 2022. The Palliative group (n = 16) comprised 13 cases with esophageal banding and 3 with tracheoesophageal fistula (TEF) division. The Definitive group (n = 9) included 5 cases with primary repair and 4 with staged repair following TEF division. The patient characteristics exhibited no significant differences between the groups. In the Definitive group, 56% (5/9) were successfully weaned off mechanical ventilation, compared with none in the Palliative group (p = 0.002). Survival-to-discharge rates were 31% (5/16) in the Palliative group and 67% (6/9) in the Definitive group. Home ventilator management was required for all 5 cases that required ventilation in the Palliative group, whereas only 17% (1/6) in the Definitive group needed it. The Palliative group also required continuous oral suction for persistent saliva removal, with two cases undergoing laryngotracheal separation. Overall, definitive surgery for EA in patients with trisomy 18 syndrome may provide enhanced respiratory stability, thereby improving the survival-to-discharge rate and overall quality of life for patients and their families.

Human Genetics of Ventricular Septal Defect.

Ventricular septal defects (VSDs) are recognized as one of the commonest congenital heart diseases (CHD), accounting for up to 40% of all cardiac malformations, and occur as isolated CHDs as well as together with other cardiac and extracardiac congenital malformations in individual patients and families. The genetic etiology of VSD is complex and extraordinarily heterogeneous. Chromosomal abnormalities such as aneuploidy and structural variations as well as rare point mutations in various genes have been reported to be associated with this cardiac defect. This includes both well-defined syndromes with known genetic cause (e.g., DiGeorge syndrome and Holt-Oram syndrome) and so far undefined syndromic forms characterized by unspecific symptoms. Mutations in genes encoding cardiac transcription factors (e.g., NKX2-5 and GATA4) and signaling molecules (e.g., CFC1) have been most frequently found in VSD cases. Moreover, new high-resolution methods such as comparative genomic hybridization enabled the discovery of a high number of different copy number variations, leading to gain or loss of chromosomal regions often containing multiple genes, in patients with VSD. In this chapter, we will describe the broad genetic heterogeneity observed in VSD patients considering recent advances in this field.

Human Genetics of Tricuspid Atresia and Univentricular Heart.

Tricuspid atresia (TA) is a rare congenital heart condition that presents with a complete absence of the right atrioventricular valve. Because of the rarity of familial and/or isolated cases of TA, little is known about the potential genetic abnormalities contributing to this condition. Potential responsible chromosomal abnormalities were identified in exploratory studies and include deletions in 22q11, 4q31, 8p23, and 3p as well as trisomies 13 and 18. In parallel, potential culprit genes include the ZFPM2, HEY2, NFATC1, NKX2-5, MYH6, and KLF13 genes. The aim of this chapter is to expose the genetic components that are potentially involved in the pathogenesis of TA in humans. The large variability in phenotypes and genotypes among cases of TA suggests a genetic network that involves many components yet to be unraveled.

Human Genetics of Hypoplastic Left Heart Syndrome.

Hypoplastic left heart syndrome (HLHS) is a severe congenital cardiovascular malformation characterized by hypoplasia of the left ventricle, aorta, and other structures on the left side of the heart. The pathologic definition includes atresia or stenosis of both the aortic and mitral valves. Despite considerable progress in clinical and surgical management of HLHS, mortality and morbidity remain concerns. One barrier to progress in HLHS management is poor understanding of its cause. Several lines of evidence point to genetic origins of HLHS. First, some HLHS cases have been associated with cytogenetic abnormalities (e.g., Turner syndrome). Second, studies of family clustering of HLHS and related cardiovascular malformations have determined HLHS is heritable. Third, genomic regions that encode genes influencing the inheritance of HLHS have been identified. Taken together, these diverse studies provide strong evidence for genetic origins of HLHS and related cardiac phenotypes. However, using simple Mendelian inheritance models, identification of single genetic variants that "cause" HLHS has remained elusive, and in most cases, the genetic cause remains unknown. These results suggest that HLHS inheritance is complex rather than simple. The implication of this conclusion is that researchers must move beyond the expectation that a single disease-causing variant can be found. Utilization of complex models to analyze high-throughput genetic data requires careful consideration of study design.

Diagnostic accuracy of cell-free DNA in maternal blood in detecting chromosomal anomalies in twin pregnancies: systematic review and meta-analysis.

OBJECTIVES: To report the diagnostic accuracy of cell-free DNA (cfDNA) in maternal blood in detecting chromosomal anomalies in twin pregnancies. METHODS: Medline, Embase and Cochrane databases were searched. The inclusion criteria were twin pregnancies undergoing cfDNA screening for Trisomies 13, 18, 21, monosomy X0 and other sex chromosomal anomalies (SCA). The index test was represented by a positive results of cfDNA test. The reference standard was represented by the karyotype results (obtained either pre or postnatally) or, in case of negative cfDNA result, by a normal neonatal phenotype. The quality of the studies was assessed using the revised tool for the quality assessment of diagnostic accuracy studies (QUADAS-2). Summary estimates of sensitivity, specificity, positive and negative likelihood ratios (LR+ and LR-) and diagnostic odds ratio (DOR), with the corresponding 95% Confidence Intervals (95% CI), were computed using the bivariate random-effects model. RESULTS: Thirty-five studies were included. cfDNA had an overall high accuracy in detecting Trisomy 21 in twin pregnancies with a sensitivity of 98.8% (95% CI 96.5-100), a specificity of 100% (95% CI 99.9-100). Sensitivity and specificity were of 94.9% (95% CI 75.6-99.1) and 100 (95% CI 99.9-100) for Trisomy 18, and 84.6% (95% C% 54.6-98.1) and 100% (95% CI 99.9-100) for Trisomy 13 . We could not compute the diagnostic accuracy of cfDNA in detecting monosomy X0 in twins, while cfDNA had a sensitivity of 100% (95% CI 71.5-100) and a specificity of 99.8% (95% CI 99.7-99.9) in detecting other SCA (11 cases). The accuracy of cfDNA in detecting Trisomy 21, 18 and 13 was similar in dichorionic and monochorionic twin pregnancies. CONCLUSION: cfDNA has a high diagnostic accuracy in detecting Trisomy 18 and 21 in twin pregnancies, irrespective of chorionicity. Accuracy in the detection of Trisomy 13 and SCA was limited by the small number of affected cases and the difficulties in the confirmation of false negative cases in case of SCA and requires confirmation in larger studies. This article is protected by copyright. All rights reserved.

Cardiac care in trisomy 18: A path to improved outcomes (case report).

Background: Trisomy 18 (also known as Edwards syndrome) is a chromosomal disorder characterized by severe developmental anomalies and cognitive deficits. Cardiac complications are a leading cause of mortality in these patients, and the role of cardiac interventions remains controversial. Case Presentation: We report a case of a full-term baby girl with trisomy 18, born via elective cesarean section. The neonate presented with pulmonary atresia and a series of other cardiac abnormalities, necessitating immediate intervention. Despite the initial challenges, including a brief episode of desaturation post-intervention, the patient responded positively to a balloon pulmonary valvuloplasty and emergency patent ductus arteriosus stent insertion, illustrating the potential benefits of cardiac interventions in patients with trisomy 18. Discussion: This case highlights the successful application of cardiac interventions in a patient with trisomy 18, challenging the notion of universally denying such treatments to this population. Our findings suggest that selective interventions can improve quality of life and stabilize the condition, supporting the need for further research to establish clear guidelines for treatment in this demographic. Conclusion: This case adds to the growing evidence supporting the feasibility and potential benefits of cardiac interventions in patients with trisomy 18, advocating for a more individualized approach to treatment.

Anesthetic Management of a Patient With Trisomy 18 Undergoing a Multilevel Spinal Fusion.

Trisomy 18 is the second most common autosomal trisomy aside from trisomy 21. Anesthesiologists were unlikely to manage such patients in the past, specifically those surviving later into childhood due to the 90% mortality rate within the first year of life and the lack of procedural options that were available. However, a paucity of literature regarding the anesthetic management of such patients exists. Trisomy 18 patients present a unique anesthetic challenge, given the presence of associated dysmorphic facial features and the involvement of multiple organ systems, leading to difficult airway and hemodynamic disturbances. In this case report, we present the anesthetic management of a 9-year-old patient with trisomy 18 undergoing a multilevel spinal fusion. Despite significant intraoperative hemorrhage, the patient was able to tolerate the procedure without complications, likely owing to the meticulous preoperative preparation and the patient's survival later into childhood. This case contributes to a small subset of literature which suggests that patients with trisomy 18 who survive later into childhood have an improved ability to tolerate general anesthesia.

Therapeutic Management and Outcomes of Hepatoblastoma in a Pediatric Patient with Mosaic Edwards Syndrome.

The mosaic form of Edwards syndrome affects 5% of all children with Edwards syndrome. The clinical phenotype is highly variable, ranging from the full spectrum of trisomy 18 to the normal phenotype. The purpose of this publication was to present the therapeutic process in an 18-month-old girl with the mosaic form of Edwards syndrome and hepatoblastoma, against the background of other cases of simultaneous occurrence of this syndrome and hepatoblastoma described so far. It appears that this particular group of patients with hepatoblastoma and Edwards syndrome can have good outcomes, provided they do not have life-threatening cardiac or other severe defects. Due to the prematurity of our patient and the defects associated with Edwards syndrome, the child required constant multidisciplinary care, but Edwards syndrome itself was not a reason to discontinue therapy for a malignant neoplasm of the liver. Regular abdominal ultrasound examination, along with AFP testing, may be helpful in the early detection of liver tumors in children with Edwards syndrome.

Chromosomal abnormalities associated with fetal pleural effusion (II): Specific and non-specific chromosome aberrations.

Fetal pleural effusion has been reported to be associated with chromosomal abnormalities, genetic syndromes, obstructive uropathy, lymphatic vessel abnormalities such as Noonan syndrome, RASopathy and congenital lymphatic anomalies, thoracic cavity defects, Rh or ABO incompatibility, non-immune hydrops fetalis, infections, congenital cardiac anomalies, metabolic diseases and hematologic diseases such as α-thalassemia. This review provides a comprehensive view of specific and non-specific chromosome aberrations associated with fetal pleural effusion which is useful for genetic counseling and fetal therapy at prenatal diagnosis of fetal pleural effusion.

"She was finally mine": the moral experience of families in the context of trisomy 13 and 18- a scoping review with thematic analysis.

INTRODUCTION: The value of a short life characterized by disability has been hotly debated in the literature on fetal and neonatal outcomes. METHODS: We conducted a scoping review to summarize the available empirical literature on the experiences of families in the context of trisomy 13 and 18 (T13/18) with subsequent thematic analysis of the 17 included articles. FINDINGS: Themes constructed include (1) Pride as Resistance, (2) Negotiating Normalcy and (3) The Significance of Time. INTERPRETATION: Our thematic analysis was guided by the moral experience framework conceived by Hunt and Carnevale (2011) in association with the VOICE (Views On Interdisciplinary Childhood Ethics) collaborative research group. RELEVANCE: This article will be of interest and value to healthcare professionals and bioethicists who support families navigating the medically and ethically complex landscape of T13/18.

Contemporary Trends in Cardiac Surgical Care for Trisomy 13 and 18 Patients Admitted to Hospitals in the United States.

OBJECTIVE: To assess rates of cardiac surgery and the clinical and demographic features that influence surgical vs nonsurgical treatment of congenital heart disease (CHD) in patients with trisomy 13 (T13) and trisomy 18 (T18) in the United States. STUDY DESIGN: A retrospective study was performed using the Pediatric Health Information System. All hospital admissions of children (<18 years of age) with T13 and T18 in the United States were identified from 2003 through 2022. International Classifications of Disease (ICD) codes were used to identify presence of CHD, extracardiac comorbidities/malformations, and performance of cardiac surgery. RESULTS: Seven thousand one hundred thirteen patients were identified. CHD was present in 62% (1625/2610) of patients with T13 and 73% (3288/4503) of patients with T18. The most common CHD morphologies were isolated atrial/ventricular septal defects (T13 40%, T18 42%) and aortic hypoplasia/coarctation (T13 21%, T18 23%). Single-ventricle morphologies comprised 6% (100/1625) of the T13 and 5% (167/3288) of the T18 CHD cohorts. Surgery was performed in 12% of patients with T13 plus CHD and 17% of patients with T18 plus CHD. For all cardiac diagnoses, <50% of patients received surgery. Nonsurgical patients were more likely to be born prematurely (P < .05 for T13 and T18). The number of extracardiac comorbidities was similar between surgical/nonsurgical patients with T13 (median 2 vs 2, P = .215) and greater in surgical vs nonsurgical patients with T18 (median 3 vs 2, P < .001). Hospital mortality was <10% for both surgical cohorts. CONCLUSIONS: Patients with T13 or T18 and CHD receive surgical palliation, but at a low prevalence (≤17%) nationally. Given operative mortality <10%, opportunity exists perhaps for quality improvement in the performance of cardiac surgery for these vulnerable patient populations.

Metastatic adrenal gland neuroblastoma in an infant with trisomy 18: A case report.

I present a patient with trisomy 18 associated with neuroblastoma. To the best of my knowledge, this is the second report of such an individual in the relevant literature. A 19-month-old girl known to have trisomy 18 presented with respiratory distress secondary to pleural effusion. Work-up showed metastatic neuroblastoma to multiple sites, and the patient's clinical situation was critical. The physician-parent's decision was not to proceed with treatment of the malignancy. Based on this report, I recommend that physicians remain vigilant and have a high level of suspicion about the potential association between neuroblastoma and trisomy 18. Accordingly, it may be necessary to consider performing serial abdominal ultrasounds and biochemical tests to screen children with trisomy 18 who survive beyond infancy.

A Long-Term Survivor of Trisomy 18.

Trisomy 18 is known for its severe prognosis, with most affected infants not surviving beyond a week, but this report sheds light on a remarkable case of a two-and-a-half-year-old girl born with Trisomy 18 who has thrived due to specialized medical care. Despite a complex medical profile, including congenital heart defects and hepatoblastoma, this patient underwent successful treatments, including multiple surgeries and chemotherapy. This case report showcases how modern medical advancements and multidisciplinary care can defy the historically grim prognosis associated with Trisomy 18, providing hope for improved outcomes and a better quality of life (QOL) for affected individuals and their families.

Long-term monitoring of gastric mucosa-associated lymphoid tissue lymphoma in patients with extra copies of the MALT1 gene.

The objective of this study was to clarify the long-term prognosis of patients with gastric mucosa-associated lymphoid tissue (MALT) lymphoma with additional copies of MALT1. In this multicenter retrospective study, we enrolled 145 patients with gastric MALT lymphoma who underwent fluorescence in situ hybridization (FISH) analysis to detect t(11;18) translocation. The patient cohort was divided into three groups: Group A (n = 87), comprising individuals devoid of the t(11;18) translocation or extra MALT1 copies; Group B (n = 27), encompassing patients characterized by the presence of the t(11;18) translocation; and Group C (n = 31), including patients with extra MALT1 copies. The clinical outcomes in each cohort were collected. Over the course of a mean follow-up of 8.5 ± 4.2 years, one patient died of progressive MALT lymphoma, while 15 patients died due to etiologies unrelated to lymphoma. The progression or relapse of MALT lymphoma was observed in 11 patients: three in Group A, two in Group B, and six in Group C. In Groups A, B, and C, the 10-year overall survival rates were 82.5%, 93.8%, and 86.4%, respectively, and the 10-year event-free survival rates were 96.1%, 96.0%, and 82.9%, respectively. The event-free survival rate in Group C was significantly lower than that in Group A. However, no differences were observed in the 10-year event-free survival rates among individuals limited to stage I or II1 disease (equivalent to excluding patients with stage IV disease in this study, as there were no patients with stage II2), with rates of 98.6%, 95.8%, and 92.3% for Groups A, B, and C, respectively. In conclusion, the presence of extra copies of MALT1 was identified as an inferior prognostic determinant of event-free survival. Consequently, trisomy/tetrasomy 18 may serve as an indicator of progression and refractoriness to therapeutic intervention in patients with gastric MALT lymphoma, particularly stage IV gastric MALT lymphoma.

The American Association for Thoracic Surgery (AATS) 2023 Expert Consensus Document: Recommendation for the care of children with trisomy 13 or trisomy 18 and a congenital heart defect.

OBJECTIVES: Recommendations for surgical repair of a congenital heart defect in children with trisomy 13 or trisomy 18 remain controversial, are subject to biases, and are largely unsupported with limited empirical data. This has created significant distrust and uncertainty among parents and could potentially lead to suboptimal care for patients. A working group, representing several clinical specialties involved with the care of these children, developed recommendations to assist in the decision-making process for congenital heart defect care in this population. The goal of these recommendations is to provide families and their health care teams with a framework for clinical decision making based on the literature and expert opinions. METHODS: This project was performed under the auspices of the AATS Congenital Heart Surgery Evidence-Based Medicine Taskforce. A Patient/Population, Intervention, Comparison/Control, Outcome process was used to generate preliminary statements and recommendations to address various aspects related to cardiac surgery in children with trisomy 13 or trisomy 18. Delphi methodology was then used iteratively to generate consensus among the group using a structured communication process. RESULTS: Nine recommendations were developed from a set of initial statements that arose from the Patient/Population, Intervention, Comparison/Control, Outcome process methodology following the groups' review of more than 500 articles. These recommendations were adjudicated by this group of experts using a modified Delphi process in a reproducible fashion and make up the current publication. The Class (strength) of recommendations was usually Class IIa (moderate benefit), and the overall level (quality) of evidence was level C-limited data. CONCLUSIONS: This is the first set of recommendations collated by an expert multidisciplinary group to address specific issues around indications for surgical intervention in children with trisomy 13 or trisomy 18 with congenital heart defect. Based on our analysis of recent data, we recommend that decisions should not be based solely on the presence of trisomy but, instead, should be made on a case-by-case basis, considering both the severity of the baby's heart disease as well as the presence of other anomalies. These recommendations offer a framework to assist parents and clinicians in surgical decision making for children who have trisomy 13 or trisomy 18 with congenital heart defect.

Double aneuploidy in a 2-month-old male with Edward syndrome and Klinefelter syndrome: a case report.

Introduction and importance: Edward syndrome is a severe chromosomal defect that occurs as a result of non-disjunction through meiosis. It presents with cardiac septal defects, horseshoe kidneys, patent ductus arteriosus, central nervous system dysgenesis, distinctive craniofacial deformities, and overriding or overlapping fingers. Klinefelter syndrome (47, XXY) is found in 1 in 660 newborn males. It is considered to be one of the most common genetic causes of infertility. It manifests with small firm testes, androgen insufficiency, and azoospermia. Case presentation: A 2-month-old male infant with a history of weakness in feeding, frequent convulsions, and an increase in cyanosis two days ago. There were multiple skeletal deformities and a tendency to spasm in the extremities, left ventricular atrophy, mitral atresia, atrial septal defect, ventricular septal defect with dilated right cavities, tricuspid valve regurgitation, pulmonary valve stenosis; and the aorta exits in the right ventricle. There is a widening of the subdural space, which was observed in the left frontal-parietal side with cortical atrophy in that area and a widening of the Sylvian fissure. A karyotype test confirmed the presence of Edward and Klinefelter syndromes. Clinical discussion: Aneuploidy is a chromosomal issue characterized by an abnormal number of a chromosome copies. The coexistence of two aneuploidies is called "double aneuploidy" which is a rare occurrence. Herein, we report a case of a 2-month-old male with Edward syndrome and Klinefelter syndrome. Conclusion: This publication aims to highlight the challenges in diagnosing and treating a complicated genetic disease.

Causes of death in individuals with trisomy 18 after the first year of life.

Mortality in individuals with trisomy 18 has significantly decreased over the past 20 years, but there is scant literature addressing the prognosis and cause of death in individuals with trisomy 18 and survival past the first year of life (YOL). This study analyzed factors associated with mortality and cause of death in a retrospective cohort of 174 individuals with trisomy 18 and survival past the first YOL, the largest such series to date. Data were collected via retrospective survey of parents of affected individuals. Prenatal diagnosis of trisomy 18; postnatal respiratory distress; maternal age > 35 years; birthweight <2000 g; brain and spinal cord defect(s); atrial and/or ventricular septal defect(s); inability to feed orally without medical assistance; and failure to meet sitting and rolling milestones were associated with mortality in this sample. Cause of death was compared between our cohort of individuals with trisomy 18 and existing literature on those with mortality before the first YOL. Individuals with trisomy 18 with mortality after the first YOL demonstrated a predominance of infectious (n = 10/22) and postoperative (n = 6/22) contributing causes of death, in contrast to the existing literature, which shows a predominance of cardiopulmonary causes of death (e.g., cardiopulmonary arrest, pulmonary hypertension). These findings demonstrate that individuals with trisomy 18 and survival past the first YOL have unique medical needs, but further research is needed to develop clinical guidelines for this growing population.

Clinical implications of crown-rump length discordance at 11 to 14 weeks in dichorionic twins.

BACKGROUND: Crown-rump length discordance, defined as ≥10% discordance, has been investigated as an early sonographic marker of subsequent growth abnormalities and is associated with an increased risk of fetal loss in twin pregnancies. Previous studies have not investigated the prevalence of fetal aneuploidy or structural anomalies in twins with discordance or the independent association of crown-rump length discordance with adverse perinatal outcomes. Moreover, data are limited on cell-free DNA screening for aneuploidy in dichorionic twins with discordance. OBJECTIVE: This study aimed to evaluate whether crown-rump length discordance in dichorionic twins between 11 and 14 weeks of gestation is associated with a higher risk of aneuploidy, structural anomalies, or adverse perinatal outcomes and to assess the performance of cell-free DNA screening in dichorionic twin pregnancies with crown-rump length discordance. STUDY DESIGN: This was a secondary analysis of a multicenter retrospective cohort study that evaluated the performance of cell-free DNA screening for the common trisomies in twin pregnancies from December 2011 to February 2020. For this secondary analysis, we included live dichorionic pregnancies with crown-rump length measurements between 11 and 14 weeks of gestation. First, we compared twin pregnancies with discordant crown-rump lengths with twin pregnancies with concordant crown-rump lengths and analyzed the prevalence of aneuploidy and fetal structural anomalies in either twin. Second, we compared the prevalence of a composite adverse perinatal outcome, which included preterm birth at <34 weeks of gestation, hypertensive disorders of pregnancy, stillbirth or miscarriage, small-for-gestational-age birthweight, and birthweight discordance. Moreover, we assessed the performance of cell-free DNA screening in pregnancies with and without crown-rump length discordance. Outcomes were compared with multivariable regression to adjust for confounders. RESULTS: Of 987 dichorionic twins, 142 (14%) had crown-rump length discordance. The prevalence of aneuploidy was higher in twins with crown-rump length discordance than in twins with concordance (9.9% vs 3.9%, respectively; adjusted relative risk, 2.7; 95% confidence interval, 1.4-4.9). Similarly, structural anomalies (adjusted relative risk, 2.5; 95% confidence interval, 1.4-4.4]) and composite adverse perinatal outcomes (adjusted relative risk, 1.2; 95% confidence interval, 1.04-1.3) were significantly higher in twins with discordance. A stratified analysis demonstrated that even without other ultrasound markers, there were increased risks of aneuploidy (adjusted relative risk, 3.5; 95% confidence interval, 1.5-8.4) and structural anomalies (adjusted relative risk, 2.7; 95% confidence interval, 1.5-4.8) in twins with CRL discordance. Cell-free DNA screening had high negative predictive values for trisomy 21, trisomy 18, and trisomy 13, regardless of crown-rump length discordance, with 1 false-negative for trisomy 21 in a twin pregnancy with discordance. CONCLUSION: Crown-rump length discordance in dichorionic twins is associated with an increased risk of aneuploidy, structural anomalies, and adverse perinatal outcomes, even without other sonographic abnormalities. Cell-free DNA screening demonstrated high sensitivity and negative predictive values irrespective of crown-rump length discordance; however, 1 false-negative result illustrated that there is a role for diagnostic testing. These data may prove useful in identifying twin pregnancies that may benefit from increased screening and surveillance and are not ascertained by other early sonographic markers.