Coarctation of the aorta, interrupted aortic arch, and hypoplastic left heart syndrome in three generations

Precision cardiovascular medicine: artificial intelligence and epigenetics for the pathogenesis and prediction of coarctation in neonates

Background: Advances in omics and computational Artificial Intelligence (AI) have been said to be key to meeting the objectives of precision cardiovascular medicine. The focus of precision medicine includes a better assessment of disease risk and understanding of disease mechanisms. Our objective was to determine whether significant epigenetic changes occur in isolated, non-syndromic CoA. Further, we evaluated the AI analysis of DNA methylation for the prediction of CoA.Methods: Genome-wide DNA methylation analysis of newborn blood DNA was performed in 24 isolated, non-syndromic CoA cases and 16 controls using the Illumina HumanMethylation450 BeadChip arrays. Cytosine nucleotide (CpG) methylation changes in CoA in each of 450,000 CpG loci were determined. Ingenuity pathway analysis (IPA) was performed to identify molecular and disease pathways that were epigenetically dysregulated. Using methylation data, six artificial intelligence (AI) platforms including deep learning (DL) was used for CoA detection.Results: We identified significant (FDR p-value ≤ .05) methylation changes in 65 different CpG sites located in 75 genes in CoA subjects. DL achieved an AUC (95% CI) = 0.97 (0.80-1) with 95% sensitivity and 98% specificity. Gene ontology (GO) analysis yielded epigenetic alterations in important cardiovascular developmental genes and biological processes: abnormal morphology of cardiovascular system, left ventricular dysfunction, heart conduction disorder, thrombus formation, and coronary artery disease.Conclusion: In an exploratory study we report the use of AI and epigenomics to achieve important objectives of precision cardiovascular medicine. Accurate prediction of CoA was achieved using a newborn blood spot. Further, we provided evidence of a significant epigenetic etiology in isolated CoA development.

Familial Screening for Left-Sided Congenital Heart Disease: What Is the Evidence? What Is the Cost?

Since the American Heart Association’s recommendation for familial screening of adults with congenital heart disease for bicuspid aortic valve, similar recommendations for other left-sided heart defects, such as hypoplastic left heart syndrome (HLHS), have been proposed. However, defining at-risk populations for these heart defects based on genetics is less straightforward due to the wide variability of inheritance patterns and non-genetic influences such as environmental and lifestyle factors. We discuss whether there is sufficient evidence to standardize echocardiographic screening for first-degree relatives of children diagnosed with HLHS. Due to variations in the inclusion of cardiac anomalies linked to HLHS and the identification of asymptomatic individuals with cardiac malformations, published studies are open to interpretation. We conclude that familial aggregation of obstructive left-sided congenital heart lesions in families with history of HLHS is not supported and recommend that additional screening should adopt a more conservative definition of what truly constitutes this heart defect. More thorough consideration is needed before embracing familial screening recommendations of families of patients with HLHS, since this could inflict serious costs on healthcare infrastructure and further burden affected families both emotionally and financially.

Novel loci for non-syndromic coarctation of the aorta in sporadic and familial cases

BACKGROUND

Coarctation of the aorta (CoA) accounts for 5-8% of all congenital heart defects. CoA can be detected in up to 20% of patients with Ullrich-Turner syndrome (UTS), in which a part or all of one of the X chromosomes is absent. The etiology of non-syndromic CoA is poorly understood. In the present work, we test the hypothesis that rare copy number variation (CNV) especially on the gonosomes, contribute to the etiology of non-syndromic CoA.

METHODS

We performed high-resolution genome-wide CNV analysis using the Affymetrix SNP 6.0 microarray platform for 70 individuals with sporadic CoA, 3 families with inherited CoA (n=13) and 605 controls. Our analysis comprised genome wide association, CNV burden and linkage. CNV was validated by multiplex ligation-dependent probe amplification.

RESULTS

We identified a significant abundance of large (>100 kb) CNVs on the X chromosome in males with CoA (p=0.005). 11 out of 51 (~ 22%) male cases had these large CNVs. Association analysis in the sporadic cohort revealed 14 novel loci for CoA. The locus on 21q22.3 in the sporadic CoA cohort overlapped with a gene locus identified in all familial cases of CoA (candidate gene TRPM2). We identified one CNV locus within a locus with high multipoint LOD score from a linkage analysis of the familial cases (SEPT9); another locus overlapped with a region implicated in Kabuki syndrome. In the familial cases, we identified a total of 7 CNV loci that were exclusively present in cases but not in unaffected family members.

CONCLUSION

Of all candidate loci identified, the TRPM2 locus was the most frequently implicated autosomal locus in sporadic and familial cases. However, the abundance of large CNVs on the X chromosome of affected males suggests that gonosomal aberrations are not only responsible for syndromic CoA but also involved in the development of sporadic and non-syndromic CoA and their male dominance.

Familial aortic coarctation: a rare cause of refractory hypertension in the elderly: a case report

We report the first case of late presentation of familial aortic coarctation, a rare cause of hypertension. Diagnosis of familial aortic coarctation in the elderly is exceptional, given that in the absence of endovascular or surgical repair patients do not usually survive beyond 50 years of age. Our case concerns a 72-year-old woman with hypertension of long evolution, control of which improved markedly after endovascular repair of the coarctation. Her son had undergone surgery for repair of aortic coarctation at the age of 23 years.

MCTP2 is a dosage-sensitive gene required for cardiac outflow tract development

Coarctation of the aorta (CoA) and hypoplastic left heart syndrome (HLHS) have been reported in rare individuals with large terminal deletions of chromosome 15q26. However, no single gene important for left ventricular outflow tract (LVOT) development has been identified in this region. Using array-comparative genomic hybridization, we identified two half-siblings with CoA with a 2.2 Mb deletion on 15q26.2, inherited from their mother, who was mosaic for this deletion. This interval contains an evolutionary conserved, protein-coding gene, MCTP2 (multiple C2-domains with two transmembrane regions 2). Using gene-specific array screening in 146 individuals with non-syndromic LVOT obstructive defects, another individual with HLHS and CoA was found to have a de novo 41 kb intragenic duplication within MCTP2, predicted to result in premature truncation, p.F697X. Alteration of Mctp2 gene expression in Xenopus laevis embryos by morpholino knockdown and mRNA overexpression resulted in the failure of proper OT development, confirming the functional importance of this dosage-sensitive gene for cardiogenesis. Our results identify MCTP2 as a novel genetic cause of CoA and related cardiac malformations.

The severe end of the spectrum: Hypoplastic left heart in Potocki-Lupski syndrome

Potocki-Lupski syndrome (PTLS) is a recently described microduplication syndrome associated with duplication 17p11.2, including the RAI1 gene. Features of PTLS include hypotonia, feeding difficulties, failure to thrive, developmental delay and behavioral abnormalities including autistic spectrum disorder, anxiety, and inattention. Cardiovascular anomalies were not recognized as a feature of duplication 17p11.2 until 2007 when noted in over 50% of a clinically characterized cohort. We report a patient with hypoplastic left heart syndrome whose diagnosis of PTLS was delayed until a genetic evaluation at age 4 years because of severe expressive language impairment. We suggest that array comparative genomic hybridization be performed in infants with severe congenital heart defects.

Autosomal dominant inheritance of left ventricular outflow tract obstruction

Most nonsyndromic congenital heart malformations (CHMs) in humans are multifactorial in origin, although an increasing number of monogenic cases have been reported recently. We describe here four new families with presumed autosomal dominant inheritance of left ventricular outflow tract obstruction (LVOTO), consisting of hypoplastic left heart (HLHS) or left ventricle (HLV), aortic valve stenosis (AS) and bicuspid aortic valve (BAV), hypoplastic aortic arch (HAA), and coarctation of the aorta (CoA). LVOTO in these families shows a wide clinical spectrum with some family members having severe anomalies such as hypoplastic left heart, and others only minor anomalies such as mild aortic valve stenosis. This supports the suggestion that all anomalies of the LVOTO spectrum are developmentally related and can be caused by a single gene defect.

Echocardiographic evaluation of asymptomatic parental and sibling cardiovascular anomalies associated with congenital left ventricular outflow tract lesions

OBJECTIVE

Left ventricular outflow tract obstructive (LVOTO) malformations are a leading cause of infant mortality from birth defects. Genetic mechanisms are likely, and there may be a higher rate of asymptomatic LVOTO anomalies in relatives of affected children. This study sought to define the incidence of cardiac anomalies in first-degree relatives of children with congenital aortic valve stenosis (AVS), coarctation of the aorta (CoA), and hypoplastic left heart syndrome (HLHS).

METHODS

A total of 113 probands with a nonsyndromic LVOTO malformation of AVS (n = 25), BAV (n = 3), CoA (n = 52), HLHS (n = 30), and aortic hypoplasia with mitral valve atresia (n = 2) were ascertained through chart review or enrolled at the time of diagnosis. Echocardiography was performed on 282 asymptomatic first-degree relatives.

RESULTS

Four studies had poor acoustic windows, leaving 278 studies for analysis. BAV were found in 13 (4.68%) first-degree relatives. The relative risk of BAV in the relatives was 5.05 (95% confidence interval: 2.2-11.7), and the broad sense heritability was 0.49, based on a general population frequency of 0.9%. BAV was more common in multiplex families compared with sporadic cases. An additional 32 relatives had anomalies of the aorta, aortic valve, left ventricle, or mitral valve.

CONCLUSIONS

The presence of an LVOTO lesion greatly increases the risk of identifying BAV in a parent or sibling, providing additional support for a complex genetic cause. The parents and siblings of affected patients should be screened by echocardiography as the presence of an asymptomatic BAV may carry a significant long-term health risk.

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.

Hypoplastic left heart and postaxial polydactyly

Two siblings are presented with hypoplastic left heart syndrome and symmetrical postaxial polydactyly affecting upper and lower limbs. This association has not been previously documented. This appears to represent a newly recognized syndrome. The inheritance is likely to be autosomal recessive, but other inheritance patterns cannot be excluded at present.

Congenital heart disease and genetic syndromes: specific correlation between cardiac phenotype and genotype

The increasing role of genetic factors in the etiology of congenital heart defects is shown by the high frequency of genetic syndromes and extracardiac malformations in these patients. The accurate study of cardiac anatomy disclosed that peculiar morphologic subtypes of heart defects are related to specific genetic conditions. The correlation between anatomic cardiac patterns and some genetic anomalies (trisomy, deletion, mutation) suggests that specific morphogenetic mechanisms put in motion by gene(s) can result in a specific cardiac phenotype. In this review we analyze the cardiac morphology and the frequent genetic syndromes in five groups of congenital heart diseases: right-sided obstructions, left-sided obstructions, atrioventricular canal defects, ventricular septal defects, and conotruncal defects. Progress in this field is due not only to new research in molecular biology, but also to the attention of clinicians to a detailed cardiac diagnosis and to specific correlations between genotype and phenotype.