Familial recurrence of nonsyndromic interrupted aortic arch and truncus arteriosus with atrioventricular canal

Common Arterial Trunk: Physiology, Imaging, and Management

Common arterial trunk (CAT), or truncus arteriosus, is a rare form of cyanotic congenital heart disease and is highly associated with DiGeorge syndrome (microdeletion 22q11.2). Prenatal diagnosis is highly feasible, allowing proper delivery planning and postnatal management. The clinical presentation is highly variable depending on the anatomical variation; however, most commonly presenting with mild cyanosis and significant tachypnea, although these patients can often go undetected in the immediate newborn period. Transthoracic echocardiography is adequate for diagnosis and detailed anatomical delineation in the majority. Additional imaging modalities such as cardiac catheterization, computed tomography angiography, or cardiac magnetic resonance imaging can be helpful in those with more complex pulmonary artery (PA) or aortic anatomy, or in the older repaired. The surgical management of CAT is complete repair in the neonatal period with resection of branch PAs from the CAT with placement of a right ventricular (RV)-to-PA conduit and patch closure of the ventricular septal defect. Overall surgical outcomes are excellent in most centers, with the expectation that the child will eventually outgrow the RV-to-PA conduit and require reoperation. Other potential reoperations or postsurgical interventions in addition to the RV-to-PA conduit may involve the truncal valve or branch PAs.

Rare copy number variants in patients with congenital conotruncal heart defects

BACKGROUND

Previous studies using different cardiac phenotypes, technologies and designs suggest a burden of large, rare or de novo copy number variants (CNVs) in subjects with congenital heart defects. We sought to identify disease-related CNVs, candidate genes, and functional pathways in a large number of cases with conotruncal and related defects that carried no known genetic syndrome.

METHODS

Cases and control samples were divided into two cohorts and genotyped to assess each subject's CNV content. Analyses were performed to ascertain differences in overall CNV prevalence and to identify enrichment of specific genes and functional pathways in conotruncal cases relative to healthy controls.

RESULTS

Only findings present in both cohorts are presented. From 973 total conotruncal cases, a burden of rare CNVs was detected in both cohorts. Candidate genes from rare CNVs found in both cohorts were identified based on their association with cardiac development or disease, and/or their reported disruption in published studies. Functional and pathway analyses revealed significant enrichment of terms involved in either heart or early embryonic development.

CONCLUSION

Our study tested one of the largest cohorts specifically with cardiac conotruncal and related defects. These results confirm and extend previous findings that CNVs contribute to disease risk for congenital heart defects in general and conotruncal defects in particular. As disease heterogeneity renders identification of single recurrent genes or loci difficult, functional pathway and gene regulation network analyses appear to be more informative. Birth Defects Research 109:271-295, 2017. © 2017 Wiley Periodicals, Inc.

Genetic factors in non-syndromic congenital heart malformations

The genetic defect in most patients with non-syndromic congenital heart malformations (CHM) is unknown, although more than 40 different genes have already been implicated. Only a minority of CHM seems to be due to monogenetic mutations, and the majority occurs sporadically. The multifactorial inheritance hypothesis of common diseases suggesting that the cumulative effect of multiple genetic and environmental risk factors leads to disease, might also apply for CHM. We review here the monogenic disease genes with high-penetrance mutations, susceptibility genes with reduced-penetrance mutations, and somatic mutations implicated in non-syndromic CHM.

Prenatal diagnosis of truncus arteriosus using multiplanar display in 4D ultrasonography

Prenatal diagnosis of truncus arteriosus with two-dimensional sonography requires expertise in fetal echocardiography. Indeed, truncus arteriosus shares with tetralogy of Fallot and pulmonary atresia with a ventricular septal defect (VSD) the sonographic finding of a single arterial trunk overriding a VSD. The diagnosis of truncus arteriosus can be confirmed when either the main pulmonary artery or its branches are visualized arising from the truncus itself. This requires sequential examination of multiple scanning planes and a process of mental reconstruction of their spatial relationships. The advantage of multiplanar imaging in three-dimensional and four-dimensional ultrasonography is that it allows for the simultaneous visualization of three orthogonal anatomic planes, which can be very important in diagnosing cardiac abnormalities. We report, first, a case of truncus arteriosus diagnosed in utero where the multiplanar display modality provided important insight into the differential diagnosis of this conotruncal anomaly, and then, review the diagnosis of truncus arteriosus on ultrasound.

Familial recurrence of nonsyndromic congenital heart defects in first degree relatives of patients with deletion 22q11.2

The majority of nonsyndromic congenital heart defects (CHDs) are considered to follow a multifactorial model of inheritance. Multiple family members affected by CHD can occasionally be detected, and the involvement of several genetic loci interacting with environmental factors is suspected to be implicated. The DiGeorge/velo-cardio-facial syndrome related to microdeletion 22q11.2 (del22) is a genetic condition associated with CHD in most of the cases. We report here on five pedigrees of patients with del22, showing occurrence of nonsyndromic CHD in a first-degree relative of the proband case. Familial aggregation of syndromic and nonsyndromic CHD as observed in our series is to be considered as an unusual pattern of recurrence. The interaction between several different genes and environmental factors, a familial susceptibility predisposing to a specific cardiac malformation, or chance association can all be hypothesized searching an explanation for these particular observations.

Persistent Truncus Arteriosus

Survival of patients with persistent truncus arteriosus, otherwise known as truncus arteriosus communis, has increased over the past several years with advances in congenital heart surgery and postoperative management. Despite the fact that ongoing debate regarding timing for surgical intervention, timing and indication for truncal valve replacement, and the ideal materials to use for the right ventricle to pulmonary artery conduit, perseverance on the part of cardiac surgeons, cardiologists, and the rest of the medical team caring for these patients has resulted in longer and improved quality of life. Early, accurate diagnosis, initial stabilization, and medical management in the perinatal period, and surgical intervention are most important in preventing or decreasing long-term morbidity and mortality.

Patterns of recurrence of congenital heart disease: an analysis of 6,640 consecutive pregnancies evaluated by detailed fetal echocardiography

OBJECTIVES

We sought to investigate the pattern of recurrence of congenital heart disease (CHD) where there is one or more affected first-degree relative.

BACKGROUND

There are little data on patterns of recurrence of different types of CHD. Analysis of a fetal series allows a high ascertainment of affected cases.

METHODS

We performed an analysis of referrals for detailed fetal echocardiography to a tertiary fetal cardiology unit, where there was a first-degree family history of CHD from 1990 to the end of 1999. Data were entered prospectively on a computerized database. Recurrences were exactly concordant if CHD was identical to the index case, and concordant for the group if belonging to a similar group of CHD.

RESULTS

A recurrence of CHD was seen in 178 (2.7%) of 6,640 pregnancies. The referral numbers for sibling, maternal, or paternal CHD cases were 5,151, 1,119, and 370, respectively. Exact concordance was seen in 37% of cases (range 0% to 80%), and group concordance was seen in 44%. In families where there were two or more recurrences, the exact concordance rate was 55%. Exact concordance rates were particularly high for isolated atrioventricular septal defects (4 of 5 [80%]) and laterality defects (7 of 11 [64%]).

CONCLUSIONS

The concordance rates of different types of CHD vary widely. Accurate diagnosis of the index case is essential for reliable counseling on patterns of recurrence. Minor CHD in the index case does not exclude more severe disease in recurrences. There appears to be significant under-referral for fetal echocardiography in paternal CHD.

Interrupted aortic arch in a child with trisomy 5q31.1q35.1 due to a maternal (20;5) balanced insertion

Complex congenital heart defects (CHD) are associated with a variety of single gene abnormalities and chromosomal rearrangements. Of the various forms of CHD, aortic arch interruption, a conotruncal heart defect, is relatively uncommon. Here we report a male neonate with aortic arch interruption type B, secundum atrial septal defect, perimembranous ventricular septal defect, patent ductus arteriosus, aortic and subaortic stenosis, and trisomy 5q31.1q35.1 resulting from a maternal balanced insertion (20;5). Chromosomal deletions, including deletion 22q11, have been reported with interrupted aortic arch (IAA); however, to our knowledge this is the first report of a trisomy of distal chromosome 5q associated with aortic arch interruption. Here we compare this child's features to other cases of trisomy 5q31.1q35.1, and review other causes of IAA. We conclude that gene dosage in this chromosomal region likely influences aortic arch development.

Long-term survival in truncus arteriosus communis type A1 associated with Ehlers-Danlos syndrome--a case report

Long-term survival is rare in patients with truncus arteriosus communis type A1 due to the early appearance of pulmonary artery obstructive changes. A 48-year-old woman with truncus arteriosus communis type A1 diagnosed with chest radiography, two-dimensional echocardiography, and cardiac catheterization is presented. The right ventricular pressure was 108 mm Hg, whereas the systolic pulmonary artery pressure was 98 mm Hg. A concomitant diagnosis of the Ehlers-Danlos syndrome was made with clinical findings. The association of Ehlers-Danlos syndrome, in which a collagen synthesis defect is observed in arterial vessels, might have interfered with pulmonary artery intimal proliferation, thus precluding the appearance of advanced pulmonary artery luminal obstructive changes and allowing long-term survival.