Genetics of atrioventricular canal defects

Partial atrioventricular canal defect and aortic coarctation associated with variants in GDF1 and NOTCH1 genes: A case report

BACKGROUND

A peculiar subgroup of patients with partial or complete atrioventricular canal defect exhibits a spectrum of left-sided obstructions including right ventricular dominance and aortic coarctation. The association of atrioventricular canal defect with left-sided obstructions is found in several genetic syndromes; however, the molecular basis of nonsyndromic atrioventricular canal defect with aortic coarctation is still poorly understood. Although some candidate genes for nonsyndromic atrioventricular canal defect are known, a complex oligogenic inheritance determined in some cases by the co-occurrence of multiple variants has also been hypothesized.

CASE REPORT

We describe a nonsyndromic infant with mesocardia with viscero-atrial situs solitus, partial atrioventricular canal defect, mild right ventricular dominance, and coarctation of the aorta. Next generation sequencing genetic testing revealed variants in two genes, GDF1 and NOTCH1, previously reported in association with atrioventricular canal defect and left-sided obstructive lesions, respectively.

CONCLUSION

The present report could support the hypothesis that the co-occurrence of cumulative variants may be considered as genetic predisposing risk factor for specific congenital heart defects.

Role of ECG in the Accidental Finding of an Atrioventricular Septal Defect in an Asymptomatic Patient Undergoing Cosmetic Surgery

Electrocardiogram (ECG) is an important diagnostic tool in identifying congenital heart disease (CHD), as demonstrated by this case of a 48-year-old female who presented for a preoperative evaluation for cosmetic surgery. ECG showed a right bundle branch block (RBBB) and first-degree atrioventricular (AV) block, and further testing revealed a primum atrial septal defect (ASD) with mitral valve anterior leaflet cleft and a membranous ventricular septal defect (VSD). She underwent successful surgical repair and was discharged home without complications. This case highlights the importance of performing additional tests like echocardiography or other imaging modalities in cases of abnormal ECG findings to accurately diagnose the underlying heart condition and ensure proper treatment.

The Burden of Congenital Heart Disease and Urogenital Lesions in a National Cohort of Hirschsprung Patients

BACKGROUND

Hirschsprung's disease (HSCR) is often associated with other congenital and chromosomal defects. This study aimed to describe the prevalence of congenital heart disease (CHD) and congenital urogenital lesions in children with HSCR, with and without Trisomy 21 and other associated anomalies, to guide appropriate screening.

METHODS

The Pediatric Health Information System was queried for patients with HSCR who underwent surgical treatment between 2016 and 2021. The prevalence of CHD, congenital urogenital lesions, Trisomy 21 and other congenital syndromes were calculated. Multivariable regression modeling was used to identify predictors of postoperative intensive care unit (ICU) admission and postoperative length of stay (LOS).

RESULTS

Of 2021 HSCR patients at 47 children's hospitals, 264 (13.1%) had CHD, 244 (12.1%) had Trisomy 21, and 103 (5.1%) had a congenital urogenital lesion. The prevalence of CHD (49.6 vs. 8.1%, P < 0.001) and of undergoing a cardiac intervention with associated CHD (40.5 vs. 23.1%, P = 0.002) were higher in patients with Trisomy 21 compared to those without. CHD was associated with an increased likelihood of postoperative ICU admission (OR: 1.6, 95% CI: 1.1, 2.2) and greater postoperative LOS (IRR: 2.6, 95% CI: 2.6, 2.7), irrespective of Trisomy 21 diagnosis.

CONCLUSIONS

The prevalence of CHD among HSCR patients (13.1%) was higher than previously reported, and CHD patients required more resource-intensive care after pull-through. While Trisomy 21 was associated with higher rates of CHD and cardiac intervention, 8.1% of HSCR patients without Trisomy 21 had CHD. Screening echocardiogram should be considered in all children diagnosed with HSCR, as CHD may influence perioperative risk stratification. However, screening renal ultrasound may have limited utility given the low prevalence of urogenital lesions in this population.

LEVEL OF EVIDENCE

Level III.

Complete Atrioventricular Canal Defect in a Non-syndromic Adult Patient: An Unusual Presentation

This case report presents a 30-year-old male patient with a history of autism spectrum disorder who experienced a drastic decline in physical activity in recent years. Upon examination, the patient was found to be relatively bedridden, lethargic, and unable to maintain an upright gait, accompanied by severe clubbing. Transthoracic echocardiography revealed a massive 4 cm complete atrioventricular canal (CAVC) defect. Although the patient was asymptomatic throughout most of his life, the CAVC defect appeared to have progressively impacted his health and activity tolerance. The importance of a multidisciplinary approach in early detection and timely intervention in managing CAVC defect is emphasized in this case.

Cellular and Molecular Mechanisms Underlying Tricuspid Valve Development and Disease

Tricuspid valve (TV) disease is highly prevalent in the general population. For ages considered "the forgotten valve" because of the predominant interest in left-side valve disease, the TV has now received significant attention in recent years, with significant improvement both in diagnosis and in management of tricuspid disease. TV is characterized by complex anatomy, physiology, and pathophysiology, in which the right ventricle plays a fundamental role. Comprehensive knowledge of molecular and cellular mechanisms underlying TV development, TV disease, and tricuspid regurgitation-related right-ventricle cardiomyopathy is necessary to enhance TV disease understanding to improve the ability to risk stratify TR patients, while also predicting valve dysfunction and/or response to tricuspid regurgitation treatment. Scientific efforts are still needed to eventually decipher the complete picture describing the etiopathogenesis of TV and TV-associated cardiomyopathy, and future advances to this aim may be achieved by combining emerging diagnostic imaging modalities with molecular and cellular studies. Overall, basic science studies could help to streamline a new coherent hypothesis underlying both the development of TV during embryogenesis and TV-associated disease and its complications in adult life, providing the conceptual basis for the ultimate and innovative field of valve repair and regeneration using tissue-engineered heart valves.

Familial partial atrioventricular septal defect in four related kindreds: case series and review of the literature

Background

Atrioventricular septal defects are common congenital heart defects and comprise a spectrum of anomalies, these defects were described in few pedigrees suggesting a familial pattern of inheritance, and they are more common in patients with chromosomal abnormalities. The familial occurrence of this particular type of congenital heart disease is uncommon and few cases have been identified as partial atrioventricular septal defect in adults apart from other chromosomal abnormalities.

Case presentation

We report four cases of adult females who were diagnosed with partial atrioventricular septal defect in four related families, our patients do not have the morphology of Down syndrome.

Conclusions

Further researches on genotyping such patients might contribute to our knowledge regarding this particular cardiac malformation.

Copy number variation analysis in Chinese children with complete atrioventricular canal and single ventricle

BACKGROUND

Congenital heart disease (CHD) is one of the most common birth defects. Copy number variations (CNVs) have been proved to be important genetic factors that contribute to CHD. Here we screened genome-wide CNVs in Chinese children with complete atrioventricular canal (CAVC) and single ventricle (SV), since there were scarce researches dedicated to these two types of CHD.

METHODS

We screened CNVs in 262 sporadic CAVC cases and 259 sporadic SV cases respectively, using a customized SNP array. The detected CNVs were annotated and filtered using available databases.

RESULTS

Among 262 CAVC patients, we identified 6 potentially-causative CNVs in 43 individuals (16.41%, 43/262), including 2 syndrome-related CNVs (7q11.23 and 8q24.3 deletion). Surprisingly, 90.70% CAVC patients with detected CNVs (39/43) were found to carry duplications of 21q11.2-21q22.3, which were recognized as trisomy 21 (Down syndrome, DS). In CAVC with DS patients, the female to male ratio was 1.6:1.0 (24:15), and the rate of pulmonary hypertension (PH) was 41.03% (16/39). Additionally, 6 potentially-causative CNVs were identified in the SV patients (2.32%, 6/259), and none of them was trisomy 21. Most CNVs identified in our cohort were classified as rare (< 1%), occurring just once among CAVC or SV individuals except the 21q11.2-21q22.3 duplication (14.89%) in CAVC cohort.

CONCLUSIONS

Our study identified 12 potentially-causative CNVs in 262 CAVC and 259 SV patients, representing the largest cohort of these two CHD types in Chinese population. The results provided strong correlation between CAVC and DS, which also showed sex difference and high incidence of PH. The presence of potentially-causative CNVs suggests the etiology of complex CHD is incredibly diverse, and CHD candidate genes remain to be discovered.

Impact of concomitant complex cardiac anatomy in nonsyndromic patients with complete atrioventricular septal defect

OBJECTIVE

We studied a cohort of patients with nonsyndromic complete atrioventricular septal defect with and without concomitant complex cardiac anatomy and compared the outcomes after surgical repair.

METHODS

Between 1993 and 2018, 62 nonsyndromic patients underwent complete atrioventricular septal defect repair. Sixteen patients (26%) had complex complete atrioventricular septal defect with variables representing concomitant cardiac anatomic complexity: tetralogy of Fallot, double outlet right ventricle, total anomalous pulmonary venous return, concomitant aortic arch reconstruction, multiple ventricular septal defects, staged repair of coarctation of the aorta, and a persisting left superior vena cava. The mean follow-up was 12.7 ± 7.9 years. Baseline variables were retrospectively evaluated and analyzed using univariable logistic regression. Survival was studied using Kaplan-Meier estimates, and group comparisons were performed using the log-rank test. A competing-risk analysis estimated the risk of reoperation with death as the competing event. A Gray's test was used to test equality of the cumulative incidence curves between groups.

RESULTS

The perioperative mortality was 3.2% (2/62). Actuarial survival was 100% versus 66.7% ± 14.9% at 10 years in the noncomplex and complex groups, respectively (P < .01). There was no significant difference in the overall reoperation rate between the noncomplex group (7/46; 15%) and the complex group (4/16; 25%) (odds ratio, 1.86; 95% confidence interval, 0.46-7.45; P = .30). The competing-risk analysis demonstrated no significant difference in reoperation between the groups (P = .28).

CONCLUSIONS

Our data show that nonsyndromic patients without complex cardiac anatomy have a good long-term survival and an acceptable risk of reoperation similar to contemporary outcomes for patients with complete atrioventricular septal defect with trisomy 21. However, the corresponding group of nonsyndromic patients with concomitant complex cardiac lesions are still a high-risk population, especially regarding mortality.