Prevalence of 22q11 deletion in fetuses with conotruncal cardiac defects: a 6-year prospective study

Morphogenetic processes in the development and evolution of the arteries of the pharyngeal arches: their relations to congenital cardiovascular malformations

The heart and aortic arch arteries in amniotes form a double circulation, taking oxygenated blood from the heart to the body and deoxygenated blood to the lungs. These major vessels are formed in embryonic development from a series of paired and symmetrical arteries that undergo a complex remodelling process to form the asymmetric arch arteries in the adult. These embryonic arteries form in the pharyngeal arches, which are symmetrical bulges on the lateral surface of the head. The pharyngeal arches, and their associated arteries, are found in all classes of vertebrates, but the number varies, typically with the number of arches reducing through evolution. For example, jawed vertebrates have six pairs of pharyngeal arch arteries but amniotes, a clade of tetrapod vertebrates, have five pairs. This had led to the unusual numbering system attributed to each of the pharyngeal arch arteries in amniotes (1, 2, 3, 4, and 6). We, therefore, propose that these instead be given names to reflect the vessel: mandibular (1st), hyoid (2nd), carotid (3rd), aortic (4th) and pulmonary (most caudal). Aberrant arch artery formation or remodelling leads to life-threatening congenital cardiovascular malformations, such as interruption of the aortic arch, cervical origin of arteries, and vascular rings. We discuss why an alleged fifth arch artery has erroneously been used to interpret congenital cardiac lesions, which are better explained as abnormal collateral channels, or remodelling of the aortic sac.

Prenatal genetic analysis of fetal aberrant right subclavian artery with or without additional ultrasound anomalies in a third level referral center

To evaluate the correlation between chromosomal abnormalities and fetal aberrant right subclavian artery (ARSA) with or without additional ultrasound anomalies (UAs). A total of 340 fetuses diagnosed with ARSA by ultrasound between December, 2015, and July, 2021, were included. All cases were subdivided into three groups: (A) 121 (35.6%) cases with isolated ARSA, (B) 91 (26.8%) cases with soft markers, and (C) 128 (37.6%) cases complicated with other UAs. Invasive testing was performed via amniotic fluid or cord blood karyotyping and chromosomal microarray analysis (CMA) in parallel, and pregnancy outcomes were followed. Karyotype abnormalities were identified in 18/340 (5.3%) patients. Karyotype abnormalities in Groups A, B, and C were 0/121 (0.0%), 7/91 (7.7%), and 11/128 (8.6%), respectively. CMA abnormalities with clinically significant variants were detected in 37/340 (10.9%) cases, of which 22q11.2 deletion syndrome and trisomy 21 accounted for 48.6% (18/37). The overall abnormal CMA with clinically significant variant detection rates in Groups A, B, and C were 3/121(2.5%), 13/91 (14.3%), and 21/128 (16.4%), respectively. There were significant difference in clinically significant CMA anomalies detection rate between Groups A and C (p < 0.05), as well as Groups A and B (p < 0.05). Comparing CMA to karyotyping showed a clinically significant incremental yield in Group C (7.8%, 10/128) compared to Groups A (2.5%, 3/121) and B (6.6%, 6/91) (p > 0.05). Fetal ARSA with additional UAs, concurred with cardiac and extra-cardiac anomalies, constitutes a high-risk factor for chromosomal aberrations, especially for pathogenic or likely pathogenic copy number variants.

Morphogenesis of the Mammalian Aortic Arch Arteries

The major vessels in mammals that take blood away from the heart and deliver it to the arms and the head take their origin from the aortic arch and are derived from the arteries formed within the embryonic pharyngeal arches. These pharyngeal arch arteries, initially symmetrical, form in a cranial to caudal sequence within the pharyngeal mesenchyme. They then undergo a complex process of remodeling to produce the asymmetrical brachiocephalic arteries as seen in the adult. A complex interaction between the tissues of the pharyngeal arches and the genes they express is required to ensure that arterial formation and remodeling is able to proceed normally. If this process is disrupted, life-threatening congenital cardiovascular malformations can occur, such as interruption of the aortic arch, isolation of individual arteries, or so-called vascular rings. Here, using state-of-the-art imaging techniques, we describe the morphogenesis of the arteries in humans and mice and the cardiovascular defects in the Tbx1 mutant mouse model. We provide details of the process of remodeling, clarifying also the morphogenesis of the external carotid artery and the so-called "migration" of the left subclavian artery.

Prenatal diagnosis of aberrant right subclavian artery: a literature review

The primary aim of this review is to estimate the prevalence of ARSA both in euploid fetuses as well as in fetuses with Down Syndrome. Secondary objectives were to estimate the association of ARSA with cardiac anomalies and chromosomal defects, especially trisomy 21 and 22q11 deletion (DiGeorge Syndrome). The incidence of ARSA in normal population varies from 0.35% to 3.5%, based on different studies. Since the first reported association between ARSA and trisomy 21 in 2015 until today, several studies have emerged to confirm different degrees of this correlation. Indeed, ARSA appears to be a clinically useful prenatal ultrasound marker for trisomy 21. Particularly, most recent studies concluded that ARSA as a non-isolated finding can be used as screening for Down syndrome. However, when ARSA is an isolated finding, various studies proved that there is no significant correlation with Down syndrome. Apart from these, ARSA appears to be associated with other chromosomal abnormalities, such as 22q11 deletion, cardiac defects and other morphological anomalies. As a conclusion ARSA should be characterized as isolated or non-isolated, as the non - isolated ARSA appears to be a clinically useful marker of Down syndrome and thus, additional testing is required when diagnosed.

Msx1 haploinsufficiency modifies the Pax9-deficient cardiovascular phenotype

BACKGROUND

Successful embryogenesis relies on the coordinated interaction between genes and tissues. The transcription factors Pax9 and Msx1 genetically interact during mouse craniofacial morphogenesis, and mice deficient for either gene display abnormal tooth and palate development. Pax9 is expressed specifically in the pharyngeal endoderm at mid-embryogenesis, and mice deficient for Pax9 on a C57Bl/6 genetic background also have cardiovascular defects affecting the outflow tract and aortic arch arteries giving double-outlet right ventricle, absent common carotid arteries and interruption of the aortic arch.

RESULTS

In this study we have investigated both the effect of a different genetic background and Msx1 haploinsufficiency on the presentation of the Pax9-deficient cardiovascular phenotype. Compared to mice on a C57Bl/6 background, congenic CD1-Pax9^-/- mice displayed a significantly reduced incidence of outflow tract defects but aortic arch defects were unchanged. Pax9^-/- mice with Msx1 haploinsufficiency, however, have a reduced incidence of interrupted aortic arch, but more cases with cervical origins of the right subclavian artery and aortic arch, than seen in Pax9^-/- mice. This alteration in arch artery defects was accompanied by a rescue in third pharyngeal arch neural crest cell migration and smooth muscle cell coverage of the third pharyngeal arch arteries. Although this change in phenotype could theoretically be compatible with post-natal survival, using tissue-specific inactivation of Pax9 to maintain correct palate development whilst inducing the cardiovascular defects was unable to prevent postnatal death in the mutant mice. Hyoid bone and thyroid cartilage formation were abnormal in Pax9^-/- mice.

CONCLUSIONS

Msx1 haploinsufficiency mitigates the arch artery defects in Pax9^-/- mice, potentially by maintaining the survival of the 3rd arch artery through unimpaired migration of neural crest cells to the third pharyngeal arches. With the neural crest cell derived hyoid bone and thyroid cartilage also being defective in Pax9^-/- mice, we speculate that the pharyngeal endoderm is a key signalling centre that impacts on neural crest cell behaviour highlighting the ability of cells in different tissues to act synergistically or antagonistically during embryo development.

Prenatal diagnosis, associated findings and postnatal outcome of fetuses with truncus arteriosus communis (TAC)

PURPOSE

To assess the spectrum of associated anomalies, the intrauterine course, postnatal outcome and management of fetuses with truncus arteriosus communis (TAC) METHODS: All cases of TAC diagnosed prenatally over a period of 8 years were retrospectively collected in two tertiary referral centers. All additional prenatal findings were assessed and correlated with the outcome. The accuracy of prenatal diagnosis was assessed.

RESULTS

39 cases of TAC were diagnosed prenatally. Mean gestational age at first diagnosis was 22 weeks (range, 13-38). Two cases were lost follow-up. Correct prenatal diagnosis of TAC was made in 21 of 24 (87.5%) cases and of TAC subtype in 19 of 21 (90.5%) cases. Prenatal diagnosis of TAC was incorrect in three cases: one newborn had aortic atresia with ventricular septal defect postnatally, one had hypoplastic right ventricle with dextro Transposition of the Great Arteries with coartation of the aorta and a third newborn had Tetralogy of Fallot with abnormal origin of the left pulmonary artery arising from the ascending aorta postnatally. These three cases were excluded from further analysis. In 9 of 34 (26.5%) cases, TAC was an isolated finding. 13 (38.2%) fetuses had additional chromosomal anomalies. Among them, microdeletion 22q11.2 was most common with a prevalence of 17.6% in our cohort. Another 3 fetuses were highly suspicious for non-chromosomal genetic syndromes due to their additional extra-cardiac anomalies, but molecular diagnosis could not be provided. Major cardiac and extra-cardiac anomalies occurred in 3 (8.8%) and in 20 (58.8%) cases, respectively. Predominantly, extra-cardiac anomalies occurred in association with chromosomal anomalies. Additionally, severe IUGR occurred in 6 (17.6%) cases. There were 14 terminations of pregnancy (41.2%), 1 (2.9%) intrauterine fetal death, 5 postnatal deaths (14.7%) and 14 (41.2%) infants were alive at last follow-up. Intention-to-treat survival rate was 70%. Mean follow-up among survivors was 42 months (range, 6-104). Postoperative health status among survivors was excellent in 11 (78.6%) infants, but 5 (46.2%) of them needed repeated re-interventions due to recurrent pulmonary artery or conduit stenosis. The other 3 (21.4%) survivors were significantly impaired due to non-cardiac problems.

CONCLUSION

TAC is a rare and complex cardiac anomaly that can be diagnosed prenatally with high precision. TAC is frequently associated with chromosomal and extra-cardiac anomalies, leading to a high intrauterine and postnatal loss rate due to terminations and perioperative mortality. Without severe extra-cardiac anomalies, postoperative short- and medium-term health status is excellent, independent of the subtype of TAC, but the prevalence of repeated interventions due to recurrent stenosis is high.

Prenatal sonographic and cytogenetic/molecular findings of 22q11.2 microdeletion syndrome in 48 confirmed cases in a single tertiary center

PURPOSE

We aimed to present the fetal ultrasound, cytogenetic/molecular testing and postmortem or postnatal clinical findings of cases with 22q11.2DS diagnosed prenatally.

MATERIALS AND METHODS

A retrospective medical record review of 48 prenatal cases diagnosed with 22q11.2DS were evaluated in our institution. Detailed ultrasound examination was performed on all fetuses. Postmortem and postnatal examinations were evaluated. The microdeletions were detected by karyotyping or microarray, then confirmed by FISH. Descriptive statistical analysis was performed.

RESULTS

Demographic data of 48 prenatal cases including 46 singletons and 1 dichorionic diamniotic twin pregnancy were evaluated. The most common extracardiac anomaly was skeletal system anomalies (25%), in which PEV was the most frequent one (20.8%). Polyhydramnios rate was detected as 31%, in 6.6% as an isolated finding. Microdeletion has been detected by karyotyping in 13 cases (13/47, 27.7%) (including 2 unbalanced translocations), by FISH in 28 cases (28/48, 58.3%), by microarray/a-CGH testing in 7 cases. Microarray analysis showed that in one case with unbalanced translocation had two consecutive deletions; one was proximal and other one distal to critical region and not encompassing TBX1 gene but CRKL and LZTR1 genes.

CONCLUSION

The current study demonstrates the whole spectrum of atypical phenotypic and genotypic variations of 22q11.2DS in the largest prenatal case series reported to date. Therefore, differential diagnosis should be considered not solely in CHD, but also in the presence of isolated clubfeet and polyhydramnios. Establishing the diagnosis in the prenatal period may allow a postnatal multidisciplinary approach, as well as affect the actual prevalence of the disease.

Should isolated aberrant right subclavian artery be ignored in the antenatal period? A management dilemma

Objective:

To investigate the frequency and types of chromosomal abnormalities in fetuses with the aberrant right subclavian artery (ARSA) and to evaluate its association with other ultrasonographic findings.

Materials and Methods:

In all, 11,666 fetal anatomic surveys were performed between March 2014 and March 2020. The cases diagnosed as ARSA were examined. Accompanying ultrasound findings and chromosomal abnormalities were collected.

Results:

ARSA was detected in 140 fetuses (1.2%). The ARSA appeared isolated in 47.1% (66/140) of cases and the remaining 52.9% (74/140) of cases were associated with cardiac or extracardiac malformations and soft markers. Chromosomal abnormalities were detected in 17.8% (25/140) of all cases. Trisomy 21 was the most common chromosomal anomaly with a prevalence of 11.4% (16/140). The corresponding rate was 3% (2/66) and 18.9% (14/74) for isolated and non-isolated ARSA, respectively. DiGeorge syndrome was detected in 3% (n=2) and Turner syndrome was in 3% (n=2) of the isolated group. ARSA was not an isolated finding in any of the 4 fetuses with trisomy 18.

Conclusion:

Isolated ARSA may be the only antenatal predictor of trisomy 21 or other chromosomal anomalies, including DiGeorge or Turner syndrome. Hence, visualization of the right subclavian artery should be a part of the fetal anatomic survey and genetic analysis should be recommended even in the absence of associated findings.

Prenatal diagnosis, associated findings and postnatal outcome of fetuses with truncus arteriosus communis (TAC)

Purpose

To assess the spectrum of associated anomalies, the intrauterine course, postnatal outcome and management of fetuses with truncus arteriosus communis (TAC)

Methods

All cases of TAC diagnosed prenatally over a period of 8 years were retrospectively collected in two tertiary referral centers. All additional prenatal findings were assessed and correlated with the outcome. The accuracy of prenatal diagnosis was assessed.

Results

Thirty nine cases of TAC were diagnosed prenatally. Mean gestational age at first diagnosis was 22 weeks (range 13–38). Two cases were lost follow-up. Correct prenatal diagnosis of TAC was made in 87.5% and of TAC subtype in 90.5%. Prenatal diagnosis was incorrect in three cases: one newborn had aortic atresia with ventricular septal defect (VSD) postnatally, one had hypo-plastic right ventricle with dextro transposition of the great arteries (d-TGA) with coarctation of the aorta and a third newborn had tetralogy of fallot (TOF) with abnormal origin of the left pulmonary artery arising from the ascending aorta postnatally. These 3 cases were excluded from further analysis.

In 26.5% of cases, TAC was an isolated finding. 38.2% of fetuses had additional chromosomal anomalies. Among them, microdeletion 22q11.2 was most common with a prevalence of 17.6% in our cohort. Another 3 fetuses were highly suspicious for non-chromosomal genetic syndromes due to their additional extra-cardiac anomalies, but molecular diagnosis could not be provided. Major cardiac and extra-cardiac anomalies occurred in between 8.8% and 58.8%, respectively. Predominantly, extra-cardiac anomalies occurred in association with chromosomal anomalies. Additionally, severe IUGR occurred in 17.6%.

There were 14 terminations of pregnancy (41.2%), 1 (2.9%) intrauterine fetal death, 5 postnatal deaths (14.7%) and 14 (41.2%) infants were alive at last follow-up. Intention-to-treat survival rate was 70%. Mean follow-up among survivors was 42 months (range 6–104). Postoperative health status among survivors was excellent in 78.6%, but 46.2% needed repeated re-interventions due to recurrent pulmonary artery or conduit stenosis. The other 21.4% of survivors were significantly impaired due to non-cardiac problems.

Conclusion

Truncus arteriosus communis is a rare and complex cardiac anomaly that can be diagnosed prenatally with high precision. TAC is frequently associated with chromosomal and extra-cardiac anomalies, leading to a high intrauterine and postnatal loss rate due to terminations and perioperative mortality. Without severe extra-cardiac anomalies, postoperative health status is excellent, independent of the subtype of TAC, but the prevalence of repeated interventions due to recurrent stenosis is high.

Fallot type of absent pulmonary valve syndrome - A case report

Absent pulmonary valve syndrome (APVS) is a rare congenital cardiac malformation characterized by absent, dysplastic, or rudimentary pulmonary valve leaflets in association with other cardiac anomalies. It has an incidence of 3-6% in cases of tetralogy of Fallot (TOF) and 0.2-0.4% of live-born infants with congenital heart disease (CHD). Absent pulmonary valve leads to dilated main pulmonary artery; presenting as a pulsatile, paracardiac cystic lesion on antenatal ultrasound (USG). We report a case of this rare anomaly in association with ventricular septal defect (VSD), TOF, and left axis deviation of heart detected at 23 weeks of gestation.

Prenatal Diagnosis and Postnatal Outcome of Fetuses with Pulmonary Atresia and Ventricular Septal Defect

PURPOSE

 To assess the intrauterine course, associated conditions and postnatal outcome of fetuses with pulmonary atresia with ventricular septal defect (PAVSD).

METHODS

 All cases of PAVSD diagnosed prenatally over a period of 10 years with a minimum follow-up of 6.5 years were retrospectively collected in 3 tertiary referral centers.

RESULTS

 50 cases of PAVSD were diagnosed prenatally. 44.0 % of fetuses had isolated PAVSD, 4.0 % had associated cardiac anomalies, 10.0 % had extra-cardiac anomalies, 38.0 % had chromosomal anomalies, 4.0 % had non-chromosomal syndromes. Among the 32 liveborn children, 56.3 % had reverse flow in the patent arterial duct, 25.0 % had major aortopulmonary collateral arteries (MAPCAs) with ductal agenesis and 18.7 % had a double supply. 17 pregnancies were terminated (34.0 %), there was 1 intrauterine fetal death (2.0 %), 1 neonatal death (2.0 %), and 6 deaths (12.0 %) in infancy. 25 of 30 (83.3 %) liveborn children with an intention to treat were alive at the latest follow-up. The mean follow-up among survivors was 10.0 years (range 6.5-15.1). 56.0 % of infants underwent staged repair, 44.0 % had one-stage complete repair. After exclusion of infants with additional chromosomal or syndromal anomalies, 88.9 % were healthy, and 11.1 % had mild limitations. The presence of MAPCAs did not differ significantly between survivors and non-survivors (p = 0.360), between one-stage or staged repair (p = 0.656) and healthy and impaired infants (p = 0.319).

CONCLUSION

 The prognosis in cases without chromosomal or syndromal anomalies is good. MAPCAs did not influence prognosis or postoperative health. The incidence of repeat interventions due to recurrent stenoses is significantly higher after staged compared with single-stage repair.

Initial validation of the diagnostic performance of Thymic-Thoracic Ratio as a marker of conotruncal abnormalities and for prediction of surgical prognosis in fetuses without 22q11.2 deletion

AIM

The present study aimed to perform an initial validation of the Thymic-Thoracic Ratio as a sonographic marker of conotruncal defects in non-syndromic fetuses and to assess the possible correlation between the grade of thymic hypoplasia and the severity of conotruncal defects.

METHODS

The study was conducted between January and June 2018 on singleton pregnant women who underwent fetal echocardiography at our institution. Fetuses with a diagnosis of conotruncal defects without 22q11.2 deletion composed the study group, while healthy appropriate for gestational age fetuses composed the control group. The Thymic-Thoracic Ratio was measured in all included fetuses and compared between the study and control group. A ROC curve analysis to evaluate the diagnostic performance of Thymic-Thoracic Ratio toward the diagnosis of conotruncal defects was performed, with determination of sensitivity, specificity, PPV, NPV, positive likelihood ratio, and negative likelihood ratio. The severity of conotruncal defects was defined with the Aristotle score in each newborn who underwent a surgical operation. The correlation between Thymic-Thoracic Ratio and Aristotle score was assessed.

RESULTS

During the study period, 23 fetuses with conotruncal defects without 22q11.2 deletion constituted the study group, and 67 healthy appropriate for gestational age fetuses were included in the control group. The T-T ratio of the study group was significantly lower than the control group (0.32 ± 0.08 vs. 0.41 ± 0.08, p < .001). The ROC curve analysis showed an AUC of 0.80 (95% CI, 0.71-0.89, p < .001) and a T-T ratio cutoff value of 0.35 for the identification of a CTD, with a sensibility of 73.9% (95% CI: 51.6-89.8%), a specificity of 79.1% (95% CI: 67.4-88.1%) a PPV of 54.8% (95% CI: 41.8-67.3%), a NPV of 89.8% (95% CI: 81.5-94.7), a positive likelihood ratio of 3.54 (95% CI 2.09-5.98), and a negative likelihood ratio of 0.33 (95% CI 0.16-0.66). A negative correlation between Aristotle score and T-T ratio was found, with a Kendall-Tau coefficient of -0.41, p = .04.

CONCLUSION

T-T ratio measurement could be useful to identify fetuses at higher risk of conotruncal heart diseases, even without chromosomic deletion, with a cutoff of 0.35. Since a lower T-T ratio seems to be related to a worse surgical neonatal prognosis, it could be possible to provide effective counseling and refer patients to high-specialized centers for fetal echocardiography and cardiac surgery.

MESP2 variants contribute to conotruncal heart defects by inhibiting cardiac neural crest cell proliferation

Conotruncal heart defects (CTDs) are closely related to defective outflow tract (OFT) development, in which cardiac neural crest cells (CNCCs) play an indispensable role. However, the genetic etiology of CTDs remains unclear. Mesoderm posterior 2 (MESP2) is an important transcription factor regulating early cardiogenesis. Nevertheless, MESP2 variants have not been reported in congenital heart defect (CHD) patients. We first identified four MESP2 variants in 601 sporadic nonsyndromic CTD patients that were not detected in 400 healthy controls using targeted sequencing. Reverse transcription-quantitative PCR (RT-qPCR), immunohistochemistry, and immunofluorescence assays revealed MESP2 expression in the OFT of Carnegie stage (CS) 11, CS13, and CS15 human embryos and embryonic day (E) 8.5, E10, and E11.5 mouse embryos. Functional analyses in HEK 293T cells, HL-1 cells, JoMa1 cells, and primary mouse CNCCs revealed that MESP2 directly regulates the transcriptional activities of downstream CTD-related genes and promotes CNCC proliferation by regulating cell cycle factors. Three MESP2 variants, c.346G>C (p.G116R), c.921C>G (p.Y307X), and c.59A>T (p.Q20L), altered the transcriptional activities of MYOCD, GATA4, NKX2.5, and CFC1 and inhibited CNCC proliferation by upregulating p21^cip1 or downregulating Cdk4. Based on our findings, MESP2 variants disrupted MESP2 function by interfering with CNCC proliferation during OFT development, which may contribute to CTDs. KEY MESSAGES: This study first analyzed MESP2 variants identified in sporadic nonsyndromic CTD patients. MESP2 is expressed in the OFT of different stages of human and mouse embryos. MESP2 regulates the transcriptional activities of downstream CTD-related genes and promotes CNCC proliferation by regulating cell cycle factor p21^cip1 or Cdk4.

Pax9 and Gbx2 Interact in the Pharyngeal Endoderm to Control Cardiovascular Development

The correct formation of the aortic arch arteries depends on a coordinated and regulated gene expression profile within the tissues of the pharyngeal arches. Perturbation of the gene regulatory networks in these tissues results in congenital heart defects affecting the arch arteries and the outflow tract of the heart. Aberrant development of these structures leads to interruption of the aortic arch and double outlet right ventricle, abnormalities that are a leading cause of morbidity in 22q11 Deletion Syndrome (DS) patients. We have recently shown that Pax9 functionally interacts with the 22q11DS gene Tbx1 in the pharyngeal endoderm for 4th pharyngeal arch artery morphogenesis, with double heterozygous mice dying at birth with interrupted aortic arch. Mice lacking Pax9 die perinatally with complex cardiovascular defects and in this study we sought to validate further potential genetic interacting partners of Pax9, focussing on Gbx2 which is down-regulated in the pharyngeal endoderm of Pax9-null embryos. Here, we describe the Gbx2-null cardiovascular phenotype and demonstrate a genetic interaction between Gbx2 and Pax9 in the pharyngeal endoderm during cardiovascular development.

Pax9 is required for cardiovascular development and interacts with Tbx1 in the pharyngeal endoderm to control 4th pharyngeal arch artery morphogenesis

Developmental defects affecting the heart and aortic arch arteries are a significant phenotype observed in individuals with 22q11 deletion syndrome and are caused by a microdeletion on chromosome 22q11. TBX1, one of the deleted genes, is expressed throughout the pharyngeal arches and is considered a key gene, when mutated, for the arch artery defects. Pax9 is expressed in the pharyngeal endoderm and is downregulated in Tbx1 mutant mice. We show here that Pax9-deficient mice are born with complex cardiovascular malformations that affect the outflow tract and aortic arch arteries with failure of the 3rd and 4th pharyngeal arch arteries to form correctly. Transcriptome analysis indicated that Pax9 and Tbx1 may function together, and mice double heterozygous for Tbx1/Pax9 presented with a significantly increased incidence of interrupted aortic arch when compared with Tbx1 heterozygous mice. Using a novel Pax9Cre allele, we demonstrated that the site of this Tbx1-Pax9 genetic interaction is the pharyngeal endoderm, therefore revealing that a Tbx1-Pax9-controlled signalling mechanism emanating from the pharyngeal endoderm is required for crucial tissue interactions during normal morphogenesis of the pharyngeal arch artery system.

Summary: A strong genetic interaction between Tbx1 and Pax9 that leads to 4th PAA-derived defects in double heterozygous mice is cell-autonomous within the pharyngeal endoderm.

Analysis of gene copy number variations in patients with congenital heart disease using multiplex ligation-dependent probe amplification

OBJECTIVE

At the molecular and cellular levels, heart development entails the precise orchestration of genetic events such as the interplay of master transcriptional regulators, signaling pathways, and chromatin remodeling. Recent studies among patients with congenital heart disease (CHD) have shown the importance of recurrent copy number variations (CNVs) in a significant number of patients. Recurrent CNVs that span several genes may affect other important organs, besides the heart. Because CHD may be the first presenting symptom in such patients, the analysis of recurrent CNVs in the genomic regions containing genes associated with CHD in patients referring to cardiology clinics may lead to an early diagnosis and the treatment of extracardiac symptoms in these patients. In this study, we aimed to screen CNVs of genomic regions including GATA4, NKX2-5, TBX5, BMP4, and CRELD1 genes and to analyse the 22q11.2 chromosomal region in apparently nonsyndromic patients with cardiac septal defects.

METHODS

Genomic regions including GATA4, NKX2-5, TBX5, BMP4, and CRELD1 genes and the 22q11.2 chromosomal region were analyzed in apparently nonsyndromic 45 patients with cardiac septal defects using the MLPA P-311 A2 Congenital Heart Disease kit. Multiplex ligationdependent probe amplification (MLPA) is an established technique for the detection of known CNVs. MLPA is substantially less expensive than array CGH and is relatively simple to use for clinicians without specific expertise in genomic technology; thus, MLPA could be used as a first-tier screening assay.

RESULTS

We screened 45 patients with cardiac septal defects for CNVs using the MLPA P-311 A2 kit. We identified three CNVs (n=3/45, 6.66%) and three 22q11 deletions. The CNVs were confirmed using fluorescence in situ hybridization.

CONCLUSION

Our study confirmed that the analysis of recurrent CNVs using the MLPA assay within pediatric cardiology clinics can led to an early syndrome diagnosis in nonsyndromic patients with CHD.

Expanding the fetal phenotype: Prenatal sonographic findings and perinatal outcomes in a cohort of patients with a confirmed 22q11.2 deletion syndrome

22q deletion syndrome (22q11.2DS) is most often correlated prenatally with congenital heart disease and or cleft palate. The extracardiac fetal phenotype associated with 22q11.2DS is not well described. We sought to review both the fetal cardiac and extracardiac findings associated with a cohort of cases ascertained prenatally, confirmed or suspected to have 22q11.2DS, born and cared for in one center. A retrospective chart review was performed on a total of 42 cases with confirmed 22q11.2DS to obtain prenatal findings, perinatal outcomes and diagnostic confirmation. The diagnosis was confirmed prenatally in 67% (28/42) and postnatally in 33% (14/42). The majority (81%) were associated with the standard LCR22A-LCR22D deletion. 95% (40/42) of fetuses were prenatally diagnosed with congenital heart disease. Extracardiac findings were noted in 90% (38/42) of cases. Additional findings involved the central nervous system (38%), gastrointestinal (14%), genitourinary (16.6%), pulmonary (7%), skeletal (19%), facial dysmorphism (21%), small/hypoplastic thymus (26%), and polyhydramnios (30%). One patient was diagnosed prenatally with a bilateral cleft lip and cleft palate. No fetus was diagnosed with intrauterine growth restriction. The average gestational age at delivery was 38 weeks and average birth weight was 3,105 grams. Sixty-two percentage were delivered vaginally and there were no fetal demises. A diagnosis of 22q11.2 deletion syndrome should be considered in all cases of prenatally diagnosed congenital heart disease, particularly when it is not isolated. Microarray is warranted in all cases of structural abnormalities diagnosed prenatally. Prenatal diagnosis of 22q11.2 syndrome can be used to counsel expectant parents regarding pregnancy outcome and guide neonatal management.

Chromosomal microarray analysis in fetuses with aberrant right subclavian artery

OBJECTIVE

To evaluate the association between aberrant right subclavian artery (ARSA), with or without additional risk factors for aneuploidy or ultrasound abnormality, and results of chromosomal microarray analysis (CMA).

METHODS

This was a multicenter study of fetuses diagnosed with ARSA that underwent genetic analysis by CMA, all samples being analyzed in the same laboratory. Clinical investigation included nuchal translucency measurement, first- and second-trimester maternal serum screening, early and late second-trimester fetal anatomy scans and fetal echocardiography. Comparative genomic hybridization microarray analysis or single-nucleotide polymorphism array technology was used for CMA of DNA samples obtained from amniotic fluid.

RESULTS

CMA results were available for 63 fetuses with ARSA. In 36 fetuses, ARSA was an isolated finding, and no pathogenic variant was found. Additional ultrasound findings and/or risk factors for aneuploidy were present in 27 fetuses, five of which had pathogenic CMA results. Of these five, trisomy 21 was detected in a fetus with echogenic intracardiac focus (EIF), 22q11 deletion was detected in a fetus with EIF and an increased risk of trisomy 21 of 1:230 from maternal serum screening, 22q11 duplication was detected in a fetus with hypoplastic right kidney and choroid plexus cyst and 22q11 deletion was detected in a fetus with right aortic arch and clubfoot. The fifth fetus had increased nuchal translucency thickness (4 mm) and a ventricular septal defect, and CMA identified both 22q11 deletion and 1q21 duplication.

CONCLUSIONS

In fetuses with isolated ARSA, an invasive procedure for CMA is not indicated. However, CMA is recommended when additional ultrasound abnormalities or risk factors for aneuploidy are observed. The chromosomal findings in four of the five cases with an abnormal CMA result in our study would not have been detected by standard fetal chromosomal testing. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Elevated birth prevalence of conotruncal heart defects in a population with high consanguinity rate

BACKGROUND

The aetiology of conotruncal heart defects is poorly understood and the birth prevalence varies geographically. The known risk factors for developing conotruncal heart defects are as follows: CHD in siblings, genetic chromosomal abnormalities, paternal age >30 years, high parity, low birth weight, prematurity, and maternal diabetes.

OBJECTIVE

The aim of this study was to characterise conotruncal heart defects, birth prevalence, mortality, and morbidity in the population of southern Israel, of whom 75% are Jewish and the rest are mostly Bedouin Arabs.

METHODS

The data were obtained from Soroka University Medical Center database of births and newborns. Conotruncal heart defects cases were identified by ICD9 codes.

RESULTS

During 1991-2011, there were 247,290 singleton live births and 393 conotruncal heart defects in Soroka University Medical Center. The birth prevalence per 10,000 live births of tetralogy of Fallot, transposition of the great arteries, and truncus arteriosus was 9.5, 5, and 1.8, respectively. In the multivariate analysis, Bedouin descent (adjusted odds ratio 2.40, p35 years (1.66, p=0.004), and siblings with congenital heart defects (1.98, p=0.005) were associated with tetralogy of Fallot, and Bedouin descent (1.61, p=0.05), siblings with congenital heart defects (2.19, p=0.004), and diabetes mellitus (7.15, p<0.001) were associated with transposition of the great arteries. In a univariate analysis, Bedouin descent (p=0.004) and congenital heart defects in siblings (p<0.001) were associated with truncus arteriosus.

CONCLUSION

We observed higher birth prevalence of conotruncal heart defects compared with the birth prevalence reported worldwide, specifically among the Bedouins, a population characterised with high consanguinity rate. Therefore, genetic counselling and early fetal echocardiograms should be encouraged, especially in high consanguinity rate populations. Naturally, further educational efforts are needed in order to decrease consanguinity and its related consequences.

Prenatal and Postnatal Survival of Fetal Tetralogy of Fallot: A Meta-analysis of Perinatal Outcomes and Associated Genetic Disorders

OBJECTIVES

The aim of this systematic review was to compare the postnatal outcomes, genetic testing results, and sonographic findings in 3 subtypes of tetralogy of Fallot.

METHODS

Thirty-six articles from the MEDLINE and EMBASE databases were selected for this review. The postnatal outcomes, karyotyping results, and sonographic findings of fetal tetralogy of Fallot with pulmonary stenosis, tetralogy of Fallot with pulmonary atresia, and tetralogy of Fallot with an absent pulmonary valve were collected and compared.

RESULTS

The survival rates (termination of pregnancy was considered fetal death) for prenatally diagnosed tetralogy of Fallot with pulmonary atresia and tetralogy of Fallot with an absent pulmonary valve at the end of neonatal period were significantly lower than the rate for tetralogy of Fallot with pulmonary stenosis (P < .05). The survival rate for tetralogy of Fallot with pulmonary atresia was also lower at birth (P < .001). Major chromosomal anomalies were more frequently detected in tetralogy of Fallot with pulmonary stenosis (P< .05); conversely, 22q11 deletion was present more often in fetuses with tetralogy of Fallot with pulmonary atresia and tetralogy of Fallot with an absent pulmonary valve (P < .001). Compared to tetralogy of Fallot with pulmonary stenosis, a right aortic arch was more associated with tetralogy of Fallot with pulmonary atresia (32.6%; P < .05), and the ductus arteriosus was almost always absent in tetralogy of Fallot with an absent pulmonary valve (87.5%; P < .001).

CONCLUSIONS

The postnatal outcomes, genetic testing results, and sonographic findings are different among subtypes of tetralogy of Fallot. Documenting those details at diagnosis can help specialists better counsel their patients.

Transposition of the Great Arteries in Fetal Life: Accuracy of Diagnosis and Short-Term Outcome

OBJECTIVE

To review our series of prenatally diagnosed transposition of the great arteries (TGA) to analyze the accuracy of fetal echocardiography for achieving a precise diagnosis of the TGA type (simple vs. complex) and to examine the short-term outcome.

METHODS

A total of 94 cases of simple and complex TGA types (ventriculoarterial discordance with atrioventricular concordance) prenatally evaluated in our referral center between 1998 and 2014 were included. Fetuses with additional congenital anomalies and those with incomplete follow-up were excluded. Prenatal diagnostic accuracy and short-term survival were analyzed for the different types of TGA.

RESULTS

The TGA type was correctly ascertained prenatally in 93.3%. Most fetuses were diagnosed with simple TGA (62.7%). There were 6 discrepancies: 5 fetuses with simple TGA had postnatally TGA + ventricular septal defect (VSD; n = 3) or TGA + VSD + coarctation of the aorta (n = 2), and 1 fetus with TGA + VSD postnatally showed severe left ventricular outflow tract obstruction. The mortality rate was 6.6%; it was higher in complex versus simple forms (12.8 vs. 1.9%, p = 0.038), and in cases with intramural coronary artery versus those without (60 vs. 3.5%, p < 0.001). We found no relationship between the arrangement of the great arteries and coronary arterial abnormalities.

CONCLUSIONS

Simple TGA has a better outcome than the complex forms. A discrepancy rate of 7% with potential influence on the prognosis of survival between the prenatal diagnosis of the TGA type and the definitive diagnosis was found.

Absent Aortic Valve in DiGeorge Syndrome

A 20-week-old fetus with the 22q11.2 deletion characteristic of DiGeorge syndrome is described with vertebral segmentation abnormalities and complex cardiovascular anomalies including an absent aortic valve. This is only the second known case of absent aortic valve in association with DiGeorge syndrome. We discuss the association of absent aortic valve with other conotruncal defects and the utility of fetal echocardiography in the diagnosis of DiGeorge syndrome.

Prenatal SNP array testing in 1000 fetuses with ultrasound anomalies: causative, unexpected and susceptibility CNVs

To evaluate the diagnostic value of single-nucleotide polymorphism (SNP) array testing in 1033 fetuses with ultrasound anomalies we investigated the prevalence and genetic nature of pathogenic findings. We reclassified all pathogenic findings into three categories: causative findings; unexpected diagnoses (UD); and susceptibility loci (SL) for neurodevelopmental disorders. After exclusion of trisomy 13, 18, 21, sex-chromosomal aneuploidy and triploidies, in 76/1033 (7.4%) fetuses a pathogenic chromosome abnormality was detected by genomic SNP array: in 19/1033 cases (1.8%) a microscopically detectable abnormality was found and in 57/1033 (5.5%) fetuses a pathogenic submicroscopic chromosome abnormality was detected. 58% (n=44) of all these pathogenic chromosome abnormalities involved a causative finding, 35% (n=27) a SL for neurodevelopmental disorder, and 6% (n=5) a UD of an early-onset untreatable disease. In 0.3% of parental samples an incidental pathogenic finding was encountered. Our results confirm that a genomic array should be the preferred first-tier technique in fetuses with ultrasound anomalies. All UDs involved early-onset diseases, which is beneficial for the patients to know. It also seems that UDs occur at a comparable frequency among microscopic and submicroscopic pathogenic findings. SL were more often detected than in pregnancies without ultrasound anomalies.

Variety of prenatally diagnosed congenital heart disease in 22q11.2 deletion syndrome

Objective

To analyze the spectrum of prenatally diagnosed congenital heart disease in a Korean population with 22q11.2 deletion syndrome, and to provide guidelines for screening 22q11.2 deletion prenatally.

Methods

This retrospective study evaluated 1,137 consecutive fetuses that had prenatal genetic testing for 22q11.2 deletion because of suspected congenital heart disease between September 2002 and December 2012, at Asan Medical Center, Seoul, Korea.

Results

Main cardiovascular diseases in the 53 fetuses with confirmed 22q11.2 deletions were tetralogy of Fallot (n = 24, 45%), interrupted aortic arch (n = 10, 19%), ventricular septal defect (n = 5, 9%), double outlet right ventricle (n = 4, 8%), and coarctation of the aorta (n = 4, 8%). Other cardiac defects were rarely associated with 22q11.2 deletion. One fetus had persistent truncus arteriosus, one had aortic stenosis, and one had hypoplastic right heart syndrome. Two fetuses had normal intracardiac anatomy with an isolated right aortic arch, and one had an isolated bilateral superior vena cava.

Conclusion

A variety of congenital heart diseases were seen during the prenatal period. Conotruncal cardiac defects except transposition of great arteries were strongly associated with 22q11.2 deletion. When such anomalies are diagnosed by fetal echocardiography, genetic testing for 22q11.2 deletion should be offered. Even if less frequent deletion-related cardiac defects are detected, other related anomalies, such as thymic hypoplasia or aplasia, should be evaluated to rule out a 22q11.2 deletion.

Prenatal diagnosis of 22q11.2 deletion syndrome in twin pregnancy: a case report

Chromosome 22q11.2 deletion syndrome is a common genetic disorder, also known as DiGeorge syndrome. It occurs in approximately 1:4,000 births, and the incidence is increasing due to affected parents bearing their own affected children. We report the prenatal diagnosis of 22q11.2 deletion syndrome by fluorescence in situ hybridization in twin fetuses having tetralogy of Fallot with absent pulmonary valve.

Conotruncal anomalies in the fetus: Referral patterns and pregnancy outcomes in a dedicated fetal cardiology unit in South India

Objective:

To describe the referral patterns and pregnancy outcomes of fetuses with conotruncal anomalies (CTA) from a fetal cardiology unit in South India.

Methods:

Records of 68 women identified to have diagnosis of CTA on fetal echocardiography (mean gestational age 26.8 ± 5.9 weeks; range 17-38 weeks) during the period 2008-2011 were reviewed.

Results:

The most common indication for referral was suspected congenital heart disease during routine antenatal scan (89.7%). The various CTA diagnosed included Tetralogy of Fallot (TOF, 44.1%), Double outlet right ventricle (DORV, 27.9%), Transposition of great vessels (TGA, 8.8%), TOF with pulmonary atresia (TOF-PA, 8.8%), TOF absent pulmonary valve (TOF-APV, 7.4%) and truncus arteriosus (TA, 2.9%). Extra cardiac anomalies were reported in 4 fetuses (7.1%). Pregnancy outcomes included pregnancies not culminating in live-birth (54.4%), delivery at term (41.2%) with 3 patients (4.4%) being lost to follow-up. Proportion of pregnancies not culminating in live-birth lesion wise include: TOF (53.3%), DORV (52.6%), TGA (50%), TOF -APV (80%), TOF-PA (50%), and TA (50%). Twenty-four babies (35.3%) received post-natal cardiac care with 5 (7.4%) undergoing neonatal surgical procedures. Seven babies (10.3%) died in neonatal period, including 2 who underwent surgery. The accuracy of fetal echo was 96.4% for primary lesion and 67.9% for complete segmental diagnosis.

Conclusions:

Pre-natal diagnosis of CTA, despite a high diagnostic accuracy, prompted utilization of post-natal tertiary cardiac care in a limited proportion of patients, including those with reparable lesions. Focus in developing countries should shift towards earlier referral, improving awareness about treatment options and a comprehensive evaluation for associated anomalies.

Congenital heart defects in La Réunion Island: a 6-year survey within a EUROCAT-affiliated congenital anomalies registry

OBJECTIVES

This study compares the prevalence and perinatal mortality of congenital heart defects on La Réunion with European (EUROCAT) standards.

METHODS AND RESULTS

Data were extracted from a EUROCAT-affiliated congenital malformations registry, covering 88,025 births during the period 2002-2007, on the whole island territory. A total of 512 congenital heart defects were registered, including 424 live births, 18 foetal deaths from 16 weeks of gestation, and 70 terminations of pregnancy. The total prevalence of congenital heart defects was 5.8 per 1000 births and live birth prevalence was 4.8 per 1000. The total prevalence of non-chromosomal congenital heart defects was 5.1 per 1000 births, of which 3% were perinatal deaths, 33.3% prenatally diagnosed, and 11.6% termination of pregnancy. Severe non-chromosomal congenital heart defects - excluding ventricular septal defects, atrial septal defects, and pulmonary valve stenosis - occurred in 2.1 per 1000 births, of which 10.3% were perinatal deaths, 59.1% prenatally diagnosed, and 24.3% termination of pregnancy. Of the severe congenital heart defects, the rates of single ventricle (0.20‰), Ebstein anomaly (0.11‰), common arterial trunk (0.25‰), and atrioventricular septal defect (0.62‰) exceeded averages found in Europe, although coarctation of the aorta was infrequent. Conversely, rates of ventricular septal defects, atrial septal defects, and pulmonary valve stenosis were inferior to European standards. Slightly less than half of the congenital heart defects of chromosomal origin were associated with Down syndrome.

CONCLUSION

In La Réunion, the total prevalence of congenital heart defects is far inferior to that found in Europe. The difference can be attributable to lower prevalences of mild congenital heart defects.

Detecting 22q11.2 deletion in Chinese children with conotruncal heart defects and single nucleotide polymorphisms in the haploid TBX1 locus

Background

Conotruncal heart defects (CTDs) are present in 75-85% of patients suffering from the 22q11.2 deletion syndrome. To date, no consistent phenotype has been consistently correlated with the 22q11.2 deletions. Genetic studies have implicated TBX1 as a critical gene in the pathogenesis of the syndrome. The aim of study was to determine the incidence of the 22q11.2 deletion in Chinese patients with CTDs and the possible mechanism for pathogenesis of CTDs.

Methods

We enrolled 212 patients with CTDs and 139 unrelated healthy controls. Both karyotypic analysis and multiplex ligation-dependent probe amplification were performed for all CTDs patients. Fluorescence in situ hybridization was performed for the patients with genetic deletions and their relatives. The TBX1 gene was sequenced for all patients and healthy controls. The χ² and Fisher's exact test were used in the statistical analysis.

Results

Thirteen of the 212 patients with CTDs (6.13%) were found to have the 22q11.2 deletion syndrome. Of the 13 cases, 11 presented with a hemizygous interstitial microdeletion from CLTCL1 to LZTR1; one presented with a regional deletion from CLTCL1 to DRCR8; and one presented with a regional deletion from CDC45L to LZTR1. There were eight sequence variants in the haploid TBX1 genes of the del22q11 CTDs patients. The frequency of one single nucleotide polymorphism (SNP) in the del22q11 patients was different from that of the non-del patients (P < 0.05), and the frequencies of two other SNPs were different between the non-del CTDs patients and controls (P < 0.05).

Conclusions

CTDs, especially pulmonary atresia with ventricular septal defect and tetralogy of Fallot, are the most common disorders associated with the 22q11.2 deletion syndrome. Those patients with both CTDs and 22q11.2 deletion generally have a typical or atypical deletion region within the TBX1 gene. Our results indicate that TBX1 genetic variants may be associated with CTDs.

Assessment of the fetal thymus by two- and three-dimensional ultrasound during normal human gestation and in fetuses with congenital heart defects

OBJECTIVES

Our objectives were to compare the size and volume of the developing fetal thymus obtained by two-dimensional ultrasound (2D-US) and three-dimensional ultrasound (3D-US), develop normative data for thymus volume (TV), and investigate TV in fetuses with congenital heart disease (CHD) and normal twin gestations.

METHODS

We studied 321 fetuses (gestational age (GA): 17-39 weeks) including 238 normal singletons, 64 normal twins and 19 singleton fetuses with CHD. We used 2D-US to assess fetal thymus maximum transverse diameter (MTD), maximum transverse area (MTA), anteroposterior diameter (APD) and superoinferior diameter (SID). TV was obtained by 3D-US using virtual organ computer-aided analysis. Measurements were adjusted for estimated fetal weight where appropriate. Linear regression analysis, general linear models and Fisher's Z-transformation were used where appropriate. A nomogram of fetal TV based on singleton gestations was produced according to previously published methods.

RESULTS

Ultrasound assessment of the fetal thymus was possible in 95.3% (306/321) of cases. Both 3D-US and 2D-US measurements were significantly correlated with GA (TV r = 0.989; MTA r = 0.918; MTD r = 0.884; APD r = 0.849; and SID r = 0.816; all P < 0.05). After Fisher's Z-transformation, the correlation between the TV and GA was significantly stronger than that between any individual 2D-US measurement and GA (P < 0.05). Normal twin fetuses had TVs similar to those of singletons adjusted for estimated fetal weight and GA (P = 0.85). TV adjusted for estimated fetal weight and GA was significantly lower in fetuses with CHD than in normal singletons (P < 0.05).

CONCLUSION

2D-US and 3D-US are useful tools for evaluation of the size and volume of the human fetal thymus through gestation. Fetal TV by 3D-US seems to reflect normal development of the thymus in utero better than do 2D-US measurements. Lower TV should be expected in association with CHDs.

Investigating 22q11.2 deletion and other chromosomal aberrations in fetuses with heart defects detected by prenatal echocardiography

Congenital heart disease (CHD) is the most common birth defect and the leading cause of mortality in the first year of life. In fetuses with a heart defect, chromosomal abnormalities are very frequent. Besides aneuploidy, 22q11.2 deletion is one of the most recognizable chromosomal abnormalities causing CHD. The frequency of this abnormality varies in nonselected populations. This study aimed to investigate the incidence of the 22q11.2 deletion and other chromosomal alterations in a Brazilian sample of fetuses with structural cardiac anomalies detected by fetal echocardiography. In a prospective study, 68 fetuses with a heart defect were evaluated. Prenatal detection of cardiac abnormalities led to identification of aneuploidy or structural chromosomal anomaly in 35.3% of these cases. None of the fetuses with apparently normal karyotypes had a 22q11.2 deletion. The heart defects most frequently associated with chromosomal abnormalities were atrioventricular septal defect (AVSD), ventricular septal defect (VSD), and tetralogy of Fallot. Autosomal trisomies 18 and 21 were the most common chromosomal abnormalities. The study results support the strong association of chromosome alterations and cardiac malformation, especially in AVSD and VSD, for which a chromosome investigation is indicated. In fetuses with an isolated conotruncal cardiopathy, fluorescence in situ hybridization (FISH) to investigate a 22q11.2 deletion is not indicated.

Prenatal and postnatal diagnosis of 22q11.2 deletion syndrome

Microdeletion of chromosome 22q11.2, the most common human deletion syndrome encompasses a wide spectrum of abnormalities. Many clinical or ultrasonographic findings may support deletion studies, either in utero or in the post-natal period. The objective of our study was to evaluate the circumstances of 22q11.2 deletion diagnosis in a single centre of genetics during a 12 years period. Testing for 22q11.2 deletion was performed in 883 cases. Congenital heart defect was the most common reason for referral. An antenatal 22q11.2 microdeletion was detected in 8 fetuses (4.7%) among 169 pregnancies, all presenting conotruncal anomalies. In one case prenatal diagnosis led to the identification of the deletion in the mildly affected father and had negative impact on the family. During the same period, postnatal 22q11.2 DS was diagnosed in 81 out of 714 patients aged from birth to 42 years (11.3%) (p = 0.02). A CHD was present in 37 (45.7%). This figure is significantly lower than the 75% commonly reported. These results suggest that deletion studies could be justifiable in fetuses with non-cardiac prenatal sonographic findings that have been reported in association with 22q11.2 DS. However, as most of these malformations are rather common and non specific, systematic 22q11.2 testing is not justifiable. In such cases, careful cardiac and thymus examination could provide additional clues for 22q11.2 testing. In addition parents should be given accurate information before antenatal or postnatal testing, including the wide variability of the clinical phenotype, the impossibility to establish a precise prognosis concerning psychomotor development and psychiatric risks.

Prevalence of 22q11.2 microdeletion in 146 patients with cardiac malformation in a referral hospital of North India

Background

The 22q11.2 microdeletion syndrome is a common condition that is associated with cardiac as well as extra-cardiac manifestations. Its prevalence and manifestations from north India has not been reported. This study was designed to determine the prevalence and ability of clinical criteria to predict 22q11.2 microdeletion.

Methods

A total of 146 cases of cardiac malformation requiring tertiary care at a teaching hospital were prospectively screened for 22q11.2 microdeletion using fluorescence in situ hybridization test. Detailed clinical information was obtained as per guidelines of Tobias, et al (1999).

Results

Nine out of 146 patients (6.16%) was found to have 22q11.2 microdeletion. All the positive patients showed the presence of extra-cardiac features of 22q11.2 microdeletion syndrome. None of the cases with isolated cardiac defect were positive for microdeletion.

Conclusions

It seems that 22q11.2 microdeletion syndrome is over-suspected in children with isolated congenital heart defects. Screening for 22q11.2 microdeletion should be considered in those cardiac malformation cases which have extra-cardiac manifestations in the form of facial dysmorphism and hypocalcaemia.

Cardiovascular anomalies associated with chromosome 22q11.2 deletion syndrome

Cardiovascular anomalies are present in 80% of neonates with 22q11.2 deletion syndrome. Three genes in chromosome 22q11.2 (TBX1, CRKL, and ERK2) have been identified whose haploinsufficiency causes dysfunction of the neural crest cell and anterior heart field and anomalies of 22q11.2 deletion syndrome. The most common diseases are conotruncal anomalies, which include tetralogy of Fallot (TF), TF with pulmonary atresia, truncus arteriosus, and interrupted aortic arch. A high prevalence of the deletion is noted in patients with TF with absent pulmonary valve, TF associated with pulmonary atresia and major aortopulmonary collateral arteries, truncus arteriosus, and type B interruption of aortic arch. Right aortic arch, aberrant subclavian artery, cervical origin of the subclavian artery, crossing pulmonary arteries, and major aortopulmonary collateral arteries are frequently associated with cardiovascular anomalies associated with 22q11.2 deletion syndrome. Virtually every type of congenital heart defect has been described early in the context of a 22q11.2 deletion. In conclusion, conotruncal anomaly associated with aortic arch and ductus arteriosus anomalies should increase the suspicion of 22q11.2 deletion.

Fetal interrupted aortic arch: 2D-4D echocardiography, associations and outcome

OBJECTIVES

To analyze fetal two-dimensional (2D) echocardiographic characteristics of interrupted aortic arch (IAA) and its different types, to explore whether the use of 4D ultrasound with B-flow imaging and spatiotemporal image correlation (STIC) can improve prenatal diagnostic accuracy, and to describe associations and outcome.

METHODS

The study comprised IAA fetuses examined exclusively by 2D conventional echocardiography during the period from 1994 to 2003, and those identified by conventional echocardiography and examined further by 4D ultrasound with B-flow imaging and STIC during the period January 2004 to July 2008, identified among fetuses examined at two referral centers for congenital heart defects (CHD). Postnatal follow-up was available in all cases. Karyotyping and fluorescent in-situ hybridization (FISH) analysis for the DiGeorge critical region (22q11.2) were performed in all cases.

RESULTS

Twenty-two cases of isolated IAA (15 Type B and seven Type A, seven and three of which, respectively, underwent B-flow imaging and STIC) were detected among 2520 cases of fetal CHD. In seven of the 15 Type B cases, a right subclavian artery arose anomalously (ARSA). 2D echocardiography failed to distinguish the type of IAA in only two cases and the ARSA in five of the seven cases. B-flow imaging and STIC successfully identified IAA types in all 10 cases examined and clearly visualized the origin and course of the ARSA, including cervical ones. FISH detected 22q11.2 microdeletion in 10 of the 15 Type B cases and an unusual association with Type A in one of the seven cases. Fetal/neonatal outcome included: eight terminations of pregnancy, one intrauterine death and four postoperative deaths in the neonatal period, and nine neonates were alive after surgery at a mean follow-up time of 58 months (range, 4 months-13 years).

CONCLUSION

Our results confirm the feasibility of prenatal characterization of IAA and its different types based on 2D echocardiographic examination, albeit with some limitations in the thorough assessment. 4D ultrasound with B-flow imaging and STIC can apparently facilitate visualization and detailed examination of the anatomical features of the IAA types, including visualization of the neck vessels, thus supplying additional information with respect to 2D sonography. As for the known association with microdeletion 22q11.2, our data indicate that Types A and B are distinct, there being a close association only with IAA Type B.

Fetal diagnosis of interrupted aortic arch

To determine the frequency of prenatal detection among liveborn patients with an interrupted aortic arch (IAA), the accuracy of prenatal diagnosis, and the anatomic features associated with IAA in the fetus. The prenatal diagnosis of an IAA is challenging. The data on the features and outcomes of fetal IAA are limited. This was a retrospective review of the fetuses and neonates diagnosed with IAA at the Children's Hospital Boston. From 1988 to 2009, 26 fetuses were diagnosed with an IAA. Of these, 21 were live born, and 5 pregnancies were terminated. Of these 21 patients, 18 were confirmed to have an IAA after birth and 3 had severe aortic coarctation. Of the 56 patients diagnosed with an IAA as neonates, 3 had a prenatal echocardiogram that did not include the correct diagnosis. Among the liveborn patients with a postnatally confirmed IAA, 24% were diagnosed prenatally, which increased from 11% during the first 7-year period to 43% more recently. Also, 15% of the prenatally diagnosed patients with IAA had a family history of structural or genetic anomalies. In fetuses with an IAA, echocardiographic Z-scores for the aortic valve and ascending aorta were significantly lower than in normal fetuses, but the left ventricular dimensions were normal. Aortopulmonary diameter ratios were abnormally low. In conclusion, although the identification of IAA on a prenatal echocardiogram can be challenging, a number of anatomic features can facilitate the diagnosis. In particular, a low aortopulmonary diameter ratio in the absence of a ventricular size discrepancy should prompt consideration of this diagnosis. Despite the diagnostic challenges, the frequency of prenatal diagnosis of the IAA is increasing.

Conotruncal anomalies in fetal life: accuracy of diagnosis, associated defects and outcome

OBJECTIVES

To assess the accuracy of prenatal echocardiography, associated anomalies, and outcome of fetuses with conotruncal anomalies (CTA).

STUDY DESIGN

We searched our database for CTA prenatally diagnosed between 1990 and 2005. We included tetralogy of Fallot (TOF), transposition of the great arteries (TGA), double-outlet right ventricle (DORV), truncus arteriosus (TA), pulmonary atresia with ventricular septal defect (PA-VSD) and posterior malalignment type VSD with aortic arch obstruction (pmtVSD-AAO). Data of 144 fetuses with complete follow-up were retrieved and analyzed.

RESULTS

The main reason for referral was suspected heart defect on a routine obstetric scan (72%). Most cases were detected < or =22 weeks (55%). The presence of a CTA was confirmed postnatally in 143 cases (99%), and the diagnosis of the first fetal echocardiography was correct in 126 (87.5%). Most diagnosis of TOF (33/36, 91.7%), TGA (34/38, 89.5%) and DORV (34/38, 89.5%) were proved correct. Inadequate assessment of the interventricular septum, the distal aortic arch and/or the severity of the right outflow tract obstruction accounted for most errors. The accuracy rate was lower in TA (11/14, 78.6%) and PA-VSD (4/7, 57.1%), with evaluation of the branch pulmonary arteries as the main source of discrepancies. In 7/18 incorrect cases subsequent scans allowed to obtain a correct diagnosis. Most fetuses (64%) had an isolated CTA. Thirty-seven had chromosomal anomalies (26%) but none were found in TGA. 22q11 deletion affected 8.7% of the tested patients. Nuchal translucency (NT) was above 95th centile in 19/104 cases (18%) in which NT were measured. Fifty cases were interrupted. The overall one-year survival rate was 71%, with differences between cases with and without associated defects (9/25, 36% vs. 57/68, 83.8%; p<0.01). The uncomplicated forms of TGA and TOF had the best survival rates (100%).

CONCLUSIONS

Most CTA can be diagnosed by fetal echocardiography with a high degree of accuracy. Chromosomal defects should always be ruled out, except for simple TGA. Current survival figures in many isolated CTA, especially simple TGA and TOF, support a change in the "classical" concept that congenital heart defects detected prenatally often have the worst outlook.

CONDENSATION

Most CTA can be diagnosed by fetal echocardiography with a high degree of accuracy. Isolated CTA are more common and most of these may have a favourable outcome.

Genetics and embryological mechanisms of congenital heart diseases

Developmental genetics of congenital heart diseases has evolved from analysis of embryo sections towards molecular genetics of cardiac morphogenesis with a dynamic view of cardiac development. Lineage analysis, transgenic animal models and retrospective clonal analysis of the developing heart led to identification of different cardiac lineages and their respective roles. Genetics of congenital heart diseases has also changed from formal genetic analysis of familial recurrences or population based analysis to screening for mutations in candidates genes identified in animal models. Based on these new concepts, genetic counselling in congenital heart diseases is based on the mechanism of a given heart defect rather than on its anatomy. Using this approach, genetic heterogeneity or intrafamilial variability of a molecular anomaly can at least be partially explained. Close cooperation between molecular embryologists, pathologists involved in heart development and paediatric cardiologists is crucial for further increase of knowledge in the field of cardiac morphogenesis and genetics of cardiac defects.

The fate of children with microdeletion 22q11.2 syndrome and congenital heart defect: clinical course and cardiac outcome

BACKGROUND

This study aimed to evaluate the cardiac outcome for children with microdeletion 22q11.2 and congenital heart defect (CHD).

METHODS

A total of 49 consecutive children with 22q11.2 and CHD were retrospectively identified. The CHD consisted of tetralogy of Fallot and variances (n = 22), interrupted aortic arch (n = 10), ventricular septal defect (n = 8), truncus arteriosus (n = 6), and double aortic arch (n = 1). Extracardiac anomalies were present in 46 of 47 children.

RESULTS

The median follow-up time was 8.5 years (range, 3 months to 23.5 years). Cardiac surgical repair was performed for 35 children, whereas 5 had palliative surgery, and 9 never underwent cardiac surgery. The median age at repair was 7.5 months (range, 2 days to 5 years). The mean hospital stay was 35 days (range, 7-204 days), and the intensive care unit stay was 15 days (range, 3-194 days). Significant postoperative complications occurred for 26 children (74%), and surgery for extracardiac malformations was required for 21 patients (43%). The overall mortality rate was 22% (11/49), with 1-year survival for 86% and 5-year survival for 80% of the patients. A total of 27 cardiac reinterventions were performed for 16 patients (46%) including 15 reoperations and 12 interventional catheterizations. Residual cardiac findings were present in 25 patients (71%) at the end of the follow-up period.

CONCLUSIONS

Children with microdeletion 22q11.2 and CHD are at high risk for mortality and morbidity, as determined by both the severity of the cardiac lesions and the extracardiac anomalies associated with the microdeletion.

[Congenitally absent pulmonary valve--analysis of ten prenatally diagnosed cases and review of the literature]

OBJECTIVES

To assess in a population of 10 fetuses diagnosed with absent pulmonary valve the incidence of associated cardiac extracardiac and chromosomal anomalies and the outcome of pregnancies.

METHOD

Retrospective analysis of data of prenatally diagnosed absent pulmonary valve cases between 1 January 1993 and 31 December 2005 in Fetal Echocardiography Laboratory of Ist Department of Obstetrics and Gynecology, Semmelweis University, Budapest, Hungary. The diagnosis was controlled with autopsy or postnatal examinations. The time of the prenatal diagnosis, indications, connected cardiac, extracardiac and chromosomal anomalies were studied.

RESULTS

Absent pulmonary valve was diagnosed prenatally in 10 pregnancies. The mean gestational age at the time of the diagnosis was 23.1 weeks (18-33 weeks). In 6 cases the malformation was diagnosed before the 24th gestational week, in 4 cases after the 24th gestational week. In 6 cases pregnancies were terminated. Fetal hydrops were found in 2 cases. Among 4 continued pregnancies one intrauterine fetal demise and two neonatal death occurred, one baby was successfully operated and survived. The Botallo duct was normally developed in five cases, in this group the absent pulmonary valve was isolated at 3 fetuses, at 1 fetus absent aortic valve and at 1 fetus tricuspid valve dysplasia were diagnosed. The Botallo duct was absent in five cases, in this group at 3 fetuses tetralogy of Fallot, at 1 fetus atrioventricular septal defect and at 1 fetus subaortic ventricular septal defect were diagnosed. Extracardiac malformations associated with cardiac abnormality at 3 fetuses. The indication for fetal echocardiography was positive family history in 3 cases, abnormal four chamber view in 2 cases, suspicion of thoracal cyst in 3 cases, fetal hydrops in 1 case, extracardiac malformation in 1 case.

CONCLUSION

The absent pulmonary valve is a severe malformation, the prognosis is poor and highly dependent on associated malformations. The correct early prenatal diagnosis is possible. The recurrence risk is higher than in multifactorial inheritance.

Velocardiofacial syndrome, DiGeorge syndrome: the chromosome 22q11.2 deletion syndromes

Velocardiofacial syndrome, DiGeorge syndrome, and some other clinical syndromes have in common a high frequency of hemizygous deletions of chromosome 22q11.2. This deletion syndrome is very common, affecting nearly one in 3000 children. Here, we focus on recent advances in cardiac assessment, speech, immunology, and pathophysiology of velocardiofacial syndrome. The complex medical care of patients needs a multidisciplinary approach, and every patient has his own unique clinical features that need a tailored approach. Patients with chromosome 22q11.2 deletion syndrome might have high level of functioning, but most often need interventions to improve the function of many organ systems.

Two-year general and neurodevelopmental outcome after neonatal complex cardiac surgery in patients with deletion 22q11.2: A comparative study

OBJECTIVE

Neonatal complex cardiac surgery carries a significant risk for adverse neurodevelopmental outcome. We hypothesized this risk to be higher in patients with deletion 22q11.2.

METHODS

From 1996 to 2004, neonates who had complex cardiac surgery at age 6 weeks or less had multisite, multidisciplinary health and neurodevelopmental outcomes (Bayley Scales of Infant Development II; mental and psychomotor developmental indices [MDI, PDI] as mean [SD] and delay [<70]) assessed at 18 to 24 months of age. All 16 patients with deletion 22q11.2 (group 1) were compared with 16 patients without deletion 22q11.2 (group 2) having undergone neonatal complex cardiac surgery at the same center and matched for cardiac lesion, socioeconomic status, and year of operation. Outcomes were compared by univariate and multivariate analyses.

RESULTS

Heart lesions in each group consisted of 6 (37.5%) cases of interrupted aortic arch, 6 (37.5%) cases of truncus arteriosus, and 4 (25%) cases of tetralogy of Fallot. Outcomes were available for all survivors. Mortality was 3 (19%) and 1 (6%) in groups 1 and 2, respectively (P = .6). MDI and PDI scores were 66.1 (10.6) and 55.0 (9.4) for group 1 and 86.3 (14.6) and 82.3 (14.3) for group 2 (P < .001). Only deletion 22q11.2 was significant in stepwise multiple regression to predict MDI and PDI scores. Mental delay occurred in 8 (61.5%) of 13 in group 1 and 2 (13.8%) of 15 in group 2 (P = .016). Psychomotor delay occurred in 11 (84.6%) of 13 in group 1 and 1 (6.7%) of 15 in group 2 (P < .001).

CONCLUSION

Neonates affected by deletion 22q11.2 and having neonatal complex cardiac surgery have significantly worse neurodevelopmental outcome than do those without deletion 22q11.2.