Search

Bicuspid aortic valve (BAV) is the most common congenital heart lesion with an estimated population prevalence of 1%. We hypothesize that specific gene variants predispose to early-onset complications of BAV (EBAV). We analyzed whole-exome sequences (WESs) to identify rare coding variants that contribute to BAV disease in 215 EBAV-affected families. Predicted damaging variants in candidate genes with moderate or strong supportive evidence to cause developmental cardiac phenotypes were present in 107 EBAV-affected families (50% of total), including genes that cause BAV (9%) or heritable thoracic aortic disease (HTAD, 19%). After appropriate filtration, we also identified 129 variants in 54 candidate genes that are associated with autosomal-dominant congenital heart phenotypes, including recurrent deleterious variation of FBN2, MYH6, channelopathy genes, and type 1 and 5 collagen genes. These findings confirm our hypothesis that unique rare genetic variants drive early-onset presentations of BAV disease., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2024 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.)

Bicuspid aortic valve (BAV), the most common congenital heart defect, is a major cause of aortic valve disease requiring valve interventions and thoracic aortic aneurysms predisposing to acute aortic dissections. The spectrum of BAV ranges from early onset valve and aortic complications (EBAV) to sporadic late onset disease. Rare genomic copy number variants (CNVs) have previously been implicated in the development of BAV and thoracic aortic aneurysms. We determined the frequency and gene content of rare CNVs in EBAV probands (n = 272) using genome-wide SNP microarray analysis and three complementary CNV detection algorithms (cnvPartition, PennCNV, and QuantiSNP). Unselected control genotypes from the Database of Genotypes and Phenotypes were analyzed using identical methods. We filtered the data to select large genic CNVs that were detected by multiple algorithms. Findings were replicated in a BAV cohort with late onset sporadic disease (n = 5040). We identified 3 large and rare (< 1,1000 in controls) CNVs in EBAV probands. The burden of CNVs intersecting with genes known to cause BAV when mutated was increased in case-control analysis. CNVs intersecting with GATA4 and DSCAM were enriched in cases, recurrent in other datasets, and segregated with disease in families. In total, we identified potentially pathogenic CNVs in 9% of EBAV cases, implicating alterations of candidate genes at these loci in the pathogenesis of BAV., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Carlisle et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Thoracic aortic aneurysms (TAAs) represent a serious health concern, as they are associated with early aortic dissection and rupture. TAA formation is triggered by genetic conditions, in particular Marfan syndrome (MFS) and bicuspid aortic valve (BAV). During the aneurysmatic process, aortic endothelial cells can undergo endothelial-to-mesenchymal transition (End-MT) with consequent phenotypic and functional alterations. We previously documented that MFS TAA is characterized by miR-632-driven End-MT exacerbation, whereas in BAV aortopathy, the occurrence of this process remains still controversial. We investigated the End-MT process and the underlined regulatory mechanisms in BAV, TAV and MFS TAA tissues. Gene expression and immunohistochemical analysis were performed in order to analyze some important miRNAs and genes characterizing End-MT. We documented that BAV endothelium maintains the expression of the endothelial homeostasis markers, such as ERG , CD31 and miR-126-5p, while it shows lower levels of miR-632 and mesenchymal markers compared with MFS. Interestingly, we also found higher levels of miR-632 in MFS patients' blood. Our findings definitively demonstrate that the End-MT process does not characterize BAV that, among the other TAAs, better maintains the endothelial features. In addition, our results suggest miR-632 as a promising diagnostic/prognostic factor in MFS aortopathy.

Lesions of the semilunar valve and the aortic arch can occur either in isolation or as part of well-described clinical syndromes. The polygenic cause of calcific aortic valve disease will be discussed including the key role of NOTCH1 mutations. In addition, the complex trait of bicuspid aortic valve disease will be outlined, both in sporadic/familial cases and in the context of associated syndromes, such as Alagille, Williams, and Kabuki syndromes. Aortic arch abnormalities particularly coarctation of the aorta and interrupted aortic arch, including their association with syndromes such as Turner and 22q11 deletion, respectively, are also discussed. Finally, the genetic basis of congenital pulmonary valve stenosis is summarized, with particular note to Ras-/mitogen-activated protein kinase (Ras/MAPK) pathway syndromes and other less common associations, such as Holt-Oram syndrome., (© 2024. The Author(s), under exclusive license to Springer Nature Switzerland AG.)

Bicuspid aortic valve (BAV) is the most common congenital heart defect with a high index of heritability. Patients with BAV have different clinical courses and disease progression. Herein, we report three siblings with BAV and clinical differences. Their clinical presentations include moderate to severe aortic regurgitation, aortic stenosis, and ascending aortic aneurysm. Genetic investigation was carried out using Whole-Exome Sequencing for the three patients. We identified two non-synonymous variants in ROBO1 and GATA5 genes. The ROBO1: p.(Ser327Pro) variant is shared by the three BAV-affected siblings. The GATA5: p.(Gln3Arg) variant is shared only by the two brothers who presented BAV and ascending aortic aneurysm. Their sister, affected by BAV without aneurysm, does not harbor the GATA5: p.(Gln3Arg) variant. Both variants were absent in the patients' fourth brother who is clinically healthy with tricuspid aortic valve. To our knowledge, this is the first association of ROBO1 and GATA5 variants in familial BAV with a potential genotype-phenotype correlation. Our findings are suggestive of the implication of ROBO1 gene in BAV and the GATA5: p.(Gln3Arg) variant in ascending aortic aneurysm. Our family-based study further confirms the intrafamilial incomplete penetrance of BAV and the complex pattern of inheritance of the disease., (© 2022. The Author(s), under exclusive licence to The Japan Society of Human Genetics.)

Background: Whole-genome sequencing in families enables deciphering of congenital heart disease causes. A shared genetic basis for familial bicuspid aortic valve (BAV) and hypoplastic left heart syndrome (HLHS) was postulated., Methods: Whole-genome sequencing was performed in affected members of 6 multiplex BAV families, an HLHS cohort of 197 probands and 546 relatives, and 813 controls. Data were filtered for rare, predicted-damaging variants that cosegregated with familial BAV and disrupted genes associated with congenital heart disease in humans and mice. Candidate genes were further prioritized by rare variant burden testing in HLHS cases versus controls. Modifier variants in HLHS proband-parent trios were sought to account for the severe developmental phenotype., Results: In 5 BAV families, missense variants in 6 ontologically diverse genes for structural ( SPTBN1 , PAXIP1 , and FBLN1 ) and signaling ( CELSR1 , PLXND1 , and NOS3 ) proteins fulfilled filtering metrics. CELSR1 , encoding cadherin epidermal growth factor laminin G seven-pass G-type receptor, was identified as a candidate gene in 2 families and was the only gene demonstrating rare variant enrichment in HLHS probands ( P =0.003575). HLHS-associated CELSR1 variants included 16 missense, one splice site, and 3 noncoding variants predicted to disrupt canonical transcription factor binding sites, most of which were inherited from a parent without congenital heart disease. Filtering whole-genome sequencing data for rare, predicted-damaging variants inherited from the other parent revealed 2 cases of CELSR1 compound heterozygosity, one case of CELSR1 - CELSR3 synergistic heterozygosity, and 4 cases of CELSR1 - MYO15A digenic heterozygosity., Conclusions: CELSR1 is a susceptibility gene for familial BAV and HLHS, further implicating planar cell polarity pathway perturbation in congenital heart disease.

Calcification of the bicuspid aortic valve (BAV) involves differential expression of various RNA genes, which is achieved through complex regulatory networks that are controlled in part by transcription factors and microRNAs. We previously found that miR-195-5p regulates the osteogenic differentiation of valvular interstitial cells (VICs) by targeting the TGF-β pathway. However, the transcriptional regulation of miR-195-5p in calcified BAV patients is not yet clear. In this study, stenotic aortic valve tissues from patients with BAVs and tricuspid aortic valves (TAVs) were collected. Candidate transcription factors of miR-195-5p were predicted by bioinformatics analysis and tested in diseased valves and in male porcine VICs. SP2 gene expression and the corresponding protein levels in BAV were significantly lower than those in TAV, and a low SP2 expression level environment in VICs resulted in remarkable increases in RNA expression levels of RUNX2, BMP2, collagen 1, MMP2, and MMP9 and the corresponding proteins. ChIP assays revealed that SP2 directly bound to the transcription promoter region of miR-195-5p. Cotransfection of SP2 shRNA and a miR-195-5p mimic in porcine VICs demonstrated that SP2 repressed SMAD7 expression via miR-195-5p, while knockdown of SP2 increased the mRNA expression of SMAD7 and the corresponding protein and attenuated Smad 2/3 expression. Immunofluorescence staining of diseased valves confirmed that the functional proteins of osteogenesis differentiation, including RUNX2, BMP2, collagen 1, and osteocalcin, were overexpressed in BAVs. In Conclusion, the transcription factor Sp2 is expressed at low levels in VICs from BAV patients, which has a negative impact on miR-195-5p expression by binding its promoter region and partially promotes calcification through a SMAD-dependent pathway., (Copyright © 2021. Published by Elsevier Inc.)

Bicuspid aortic valve (BAV) is a common congenital heart disease, with a 10-fold higher prevalence in first-degree relatives. BAV has different phenotypes based on the morphology of cusp fusion. These phenotypes are associated with different clinical courses and prognoses. Currently, the determinants of the valve phenotype are unknown. In this study we evaluated the role of genetics using familial cohorts. Patients with BAV and their first-degree relatives were evaluated by echocardiography. The concordance in BAV phenotype between pairs of family members was calculated and compared with the concordance expected by chance. We then performed a systematic literature review to identify additional reports and calculated the overall concordance rate. During the study period, 70 cases from 31 families and 327 sporadic cases were identified. BAV was diagnosed in 14% of the screened relatives. The proportions of the morphologies identified was: 12.3% for type 0, 66.2% for type 1-LR, 15.4% for type 1-RN, 4.6% for type 1-NL, and 1.5% for type 2. For the assessment of morphologic concordance, we included 120 pairs of first-degree relatives with BAV from our original cohort and the literature review. Concordance was found only in 62% of the pairs which was not significantly higher than expected by chance. In conclusion, our finding demonstrates intrafamilial variability in BAV morphology, suggesting that morphology is determined by factors other than Mendelian genetics. As prognosis differs by morphology, our findings may suggest that clinical outcomes may vary even between first-degree relatives., Competing Interests: Disclosures All authors have no conflicts of interest to declare., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Ascending aortic diameter is not an accurate parameter for surgical indication in patients with bicuspid aortic valve (BAV). Thus, the present study aimed to identify specific microRNAs (miRNAs/miRs) and their expression levels in aortic wall aneurysm associated with BAV according to severity of medial degeneration and to elucidate the association between the tissue expression levels of the miRNAs with their expression in plasma. Aortic wall and blood specimens were obtained from 38 patients: 12 controls and 26 patients with BAV with ascending aortic aneurysm. Of the patients with BAV, 19 had cusp fusions of right and left, 5 of right and non‑coronary, and 2 of left and non‑coronary. Two groups of patients were identified according to the grade of medial degeneration (MD): Low‑grade D group (LGMD) and high‑grade MD group (HGMD). Expression level of miR‑122, miR‑130, miR‑718 and miR‑486 were validated by reverse transcription‑quantitative PCR in plasma and tissue samples. MD grade was found to be independent from the BAV phenotype. The HGD group showed increased expression levels of MMP‑9 and MMP‑2, and an increase in the number of apoptotic cells. Tissue expression levels of miR‑718 and miR‑122 were lower in the LGMD and HGD groups compared with expression in the control group; the HGD group showed increased levels of miR‑486. Plasma expression levels of miR‑122 were decreased in the LGMD and HGD groups, and miR‑718 was only reduced in the HGD group. On the contrary, expression of miR‑486 was increased in the LGMD and HGD groups. The data suggested that miR‑486 may be considered as a non‑invasive biomarker of aortic wall degeneration. Dysregulation of this putative biomarker may be associated with high risk of dissection and rupture in patients with BAV.

Background: Wolfram syndrome (WFS) is characterized by deafness, diabetes mellitus, and diabetes insipidus along with optic atrophy. WFS has an autosomal recessive mode of inheritance and is due to variants in WFS1 and CISD2., Methods: We evaluated the underlying molecular etiology of three affected members of a consanguineous family with hearing impairment, bicuspid aortic valve, diabetes mellitus and insipidus, clinodactyly, and gastrointestinal tract abnormalities via exome sequencing approach. We correlated clinical and imaging data with the genetic findings and their associated phenotypes., Results: We identified a homozygous missense variant p.(Asn1097Lys) in CDK13, a gene previously associated with autosomal dominant congenital heart defects, dysmorphic facial features, clinodactyly, gastrointestinal tract abnormalities, intellectual developmental disorder, and seizures with variable phenotypic features., Conclusion: We report a homozygous variant in CDK13 and suggest that this gene causes an autosomal recessive disorder with hearing impairment, bicuspid aortic valve, diabetes mellitus and insipidus, clinodactyly, and gastrointestinal tract abnormalities., (© 2021. The Author(s).)

This International Consensus Classification and Nomenclature for the congenital bicuspid aortic valve condition recognizes 3 types of bicuspid valves: 1. The fused type (right-left cusp fusion, right-non-coronary cusp fusion and left-non-coronary cusp fusion phenotypes); 2. The 2-sinus type (latero-lateral and antero-posterior phenotypes); and 3. The partial-fusion (forme fruste) type. The presence of raphe and the symmetry of the fused type phenotypes are critical aspects to describe. The International Consensus also recognizes 3 types of bicuspid valve-associated aortopathy: 1. The ascending phenotype; 2. The root phenotype; and 3. Extended phenotypes., (Copyright © 2021 Jointly between The Society of Thoracic Surgeons, the American Association for Thoracic Surgery, the European Association for Cardio-Thoracic Surgery, and the Radiological Society of North America. Published by Elsevier Inc. All rights reserved.)

Background: The bicuspid aortic valve (BAV) is prone to ascending aortic dilatation (AAD) involving both the tubular segment and the aortic root. The genetic factor was proposed as one of the most important mechanisms for AAD. We hypothesized that the rare genetic variants mainly contribute to the pathogenesis of aortic roots in affected individuals., Methods: The diameter of aortic root or ascending aorta ≥ 40 mm was counted as AAD. The targeted next-generation sequencing of 13 BAV-associated genes were performed on a continuous cohort of 96 unrelated BAV patients. The rare variants with allele frequency < 0.05% were selected and analyzed. Variants frequency was compared against the Exome aggregation consortium database. The pathogenicity of the genetic variants was evaluated according to the American College of Medical Genetics and Genomics guidelines., Results: A total of 27 rare nonsynonymous coding variants involving 9 genes were identified in 25 individuals. The burden analysis revealed that variants in GATA5, GATA6, and NOTCH1 were significantly associated with BAV. Eighty percent of the pathogenic variants were detected in root group. The detection rate of rare variants was higher in root dilatation group (71.4%) compared with normal aorta (29.0%) and tubular dilatation groups (29.6%) (P = 0.018). The rare variant was identified as the independent risk factor of root dilatation [P = 0.014, hazard ratio = 23.9, 95% confidence interval (1.9-302.9)]., Conclusions: Our results presented a broad genetic spectrum in BAV patients. The rare variants of BAV genes contribute the most to the root phenotype among BAV patients., (© 2021. The Author(s).)

The incidence of bicuspid aortic valves (BAV) is high in the whole population, BAV-related thoracic aortic aneurysm (TAA) is accompanied by many adverse vascular events. So far, there are two key points in dealing with BAV-related TAA. First is fully understanding on its pathogenesis. Second is optimizing surgical intervention time. This review aims to illustrate the potential role of miRNAs in both aspects, that is, how miRNAs are involved in the occurrence and progression of BAV-related TAA, and the feasibilities of miRNAs as biomarkers., (© 2021. The Author(s).)

Background: The dilation of the aorta that occurs as a consequence of a congenitally bicuspid aortic valve (BAV) is associated with a risk of dissection, aneurysm or rupture. With progressive aortopathy, surgery is often recommended, but current patient selection strategies have limitations. A blood-based assay to identify those who would most benefit from prophylactic surgery would be an important medical advance. In a proof-of-concept study, we sought to identify aorta-specific differentially methylated regions (DMRs) detectable in plasma cell-free DNA (cfDNA) obtained from patients undergoing surgery for BAV-associated aortopathy., Methods: We used bioinformatics and publicly available human methylomes to identify aorta-specific DMRs. We used data from 4D-flow cardiac magnetic resonance imaging to identify regions of elevated aortic wall shear stress (WSS) in patients with BAV-associated aortopathy undergoing surgery and correlated WSS regions with aortic tissue cell death assessed using TUNEL staining. Cell-free DNA was isolated from patient plasma, and levels of candidate DMRs were correlated with aortic diameter and aortic wall cell death., Results: Aortic wall cell death was not associated with maximal aortic diameter but was significantly associated with elevated WSS. We identified 24 candidate aorta-specific DMRs and selected 4 for further study. A DMR on chromosome 11 was specific for the aorta and correlated significantly with aortic wall cell death. Plasma levels of total and aorta-specific cfDNA did not correlate with aortic diameter., Conclusions: In a cohort of patients undergoing surgery for BAV-associated aortopathy, elevated WSS created by abnormal flow hemodynamics was associated with increased aortic wall cell death which supports the use of aorta-specific cfDNA as a potential tool to identify aortopathy and stratify patient risk., (© 2021. The Author(s).)

Pathogenic heterozygous variants in the NOTCH1 gene are known to be associated with both left and right-sided congenital cardiac anomalies with strikingly incomplete penetrance and variable phenotypic expressivity. De novo NOTCH1 whole gene deletion has been reported rarely in the literature and its association with cardiac defects is less well established. Here, we report four cases of NOTCH1 gene deletion from two families associated with a spectrum of congenital heart defects from bicuspid aortic valve to complex cardiac anomalies. This is the first description of a familial NOTCH1 deletion, showing apparently high penetrance, which may be unique to this mechanism of disease. Immunohistochemical staining of cardiac tissue demonstrated reduced levels of NOTCH1 expression in both the left and right ventricular outflow tracts. These cases suggest that haploinsufficiency caused by NOTCH1 gene deletion is associated with both mild and severe cardiac defects, similar to those caused by pathogenic variants in the gene, but with apparently higher, if not complete, penetrance., (© 2021 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Size threshold for aortic surgery in bicuspid aortic valve (BAV) is debated. Connective tissue disorders (CTDs) are claimed as a clinical turning point, suggesting early surgery in BAV patients with CTD. Thus, we aimed at developing a score to detect high risk of carrying CTDs in consecutive BAVs from primary care. Ninety-eight BAVs without ectopia lentis or personal/family history of aortic dissection were studied at the Marfan syndrome Tuscany Referral Center. Findings were compared with those detected in 84 Marfan patients matched for sex and age. We selected traits with high statistical difference between MFS and BAV easily obtainable by cardiologists and primary-care internists: mitral valve prolapse, myopia ≥ 3DO, pectus carenatum, pes planus, wrist and thumb signs, and difference between aortic size at root and ascending aorta ≥ 4 mm. Clustering of ≥ 3 of these manifestations were more frequent in Marfan patients than in BAVs (71.4% vs 6.1%, p < 0.0001) resulting into an Odds Ratio to be affected by MFS of 38.3 (95% confidence intervals 14.8-99.3, p < 0.0001). We propose a score assembling simple clinical and echocardiographic variables resulting in an appropriate referral pattern of BAVs from a primary-care setting to a tertiary center to evaluate the presence of a potential, major CTD.

Bicuspid aortic valve (BAV) is characterized by elevated risk of aortic dilatation and aneurysm. Although genetic susceptibility is suspected to influence on the development of BAV aortopathy, clinical application of genetic markers still needs validation in BAV entities with strictly defined phenotypic features. The 'root phenotype' represents a young, male predominant, and severely aortic regurgitant BAV population prone to aortic root dilatation. The present study launched a two-step genetic survey to evaluate the clinical significance of germline genetic markers in BAV patients. The whole-exome sequencing (WES) cohort consisted of 13 BAV patients with 'root phenotype' under the age of 40 years. We identified 28 different heterozygous missense mutations in 19 genes from the WES cohort, among which six variants (COL1A2 R882C, COL5A1 I1161F, ACVRL1 R218W, NOTCH1 P1227S, MYLK S243W, MYLK D717Y) were identified as pathogenic variants via unanimous agreement of in silico prediction tool analysis, and three variants (C1R I345L, TGFBR2 V216I, FBN2 G475V) were identified as recurrent variants. The panel of nine genetic markers was tested in an independent validation cohort of 154 BAV patients consecutively included from January to May 2018 in our institution. The validation cohort demonstrated 71.4% male predominance and the average age of 57 ± 13 years, among which 26.6% showed aortic root dilatation and 66.9% ascending aortic dilatation. Genetic markers were found in 32 patients, including 18 with C1R I345L, 11 with TGFBR2 V216I, 2 with FBN2 G475V, and 1 with both TGFBR2 V216I and MYLK D717Y. BAV patients carrying these genetic markers demonstrated younger age [(51 ± 12) vs. (58 ± 13) years, P = 0.014], more moderate to severe aortic regurgitation (56.2% vs. 33.6%, P = 0.019), elevated prevalence of mitral valve prolapse (9.4% vs. 0.8%, P = 0.028) and aortic root dilatation (62.5% vs. 17.2%, P < 0.001) but not ascending aortic dilatation than those without these markers. The early-onset 'root phenotype' entities displayed great value for BAV genetic surveys. As one of the promising complements of the current risk stratification system, recurrent germline mutations in TGFBR2, C1R, FBN2 genes could be identified and applied as genetic markers of elevated susceptibility for aortic root but not ascending aortic dilatation among BAV patients.

We report on a young patient with a bicuspid aortic valve operated on for type A acute aortic dissection because of a blunt thoracic trauma. Aortic root replacement and ascending aortic and total arch repair together with the postoperative course were uneventful. Multigenerational genetic analyses revealed mutations in the NOTCH1 and ACTA2 genes in the patient and his father. The screening of his parents and children revealed no bicuspid aortic valve or aortic root dilation. This exceptionally rare case of double-hit mutations and the presence of blunt trauma reveals the complex etiology of aortic dissection in patients with a bicuspid aortic valve., (Copyright © 2021 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Aim: SNPs in miRNA machinery genes may affect miRNA function by impacting their biogenesis. Here, we investigated the association between three SNPs in miRNA machinery genes ( DICER rs1057035, DROSHA rs10719 and XPO5 rs11077) and bicuspid aortic valve (BAV). Materials & methods: Three polymorphisms were analyzed in 177 BAV patients and 414 healthy subjects by using a TaqMan ® SNP assay. Results: The frequencies of XPO5 rs11077 genotype were significantly different between BAV patients and controls (p = 0.022). On multivariate logistic regression analysis, the XPO5 rs11077 C allele resulted a significant predictor of BAV (odds ratio adjusted  = 0.65; CI: 0.42-0.98; p = 0.047). Conclusion: The XPO5 rs11077 SNP was associated with a decreased BAV risk supporting the causative role of miRNAs in aortic valve development.

Objectives: We aimed to elucidate the correlation between expression patterns of aortic tissue microRNAs and the aortopathy formation in bicuspid aortic valve (BAV) disease., Methods: All 65 patients who underwent elective aortic valve repair/replacement +/- proximal aortic replacement due to BAV disease with or without concomitant aortic aneurysm were identified from our BAV registry. Aortic tissue was collected intraoperatively from the ascending aorta at the greater and lesser curvature. Aortic tissue microRNAs analysis included 11 microRNAs ( miR-1, miR-17, miR-18a, miR-19a, miR-20a, miR-21, miR-29b, miR-106a, miR-133a, miR-143 and miR-145 ). Furthermore, analysis of MMP2, TIMP1/2 mRNA and the protein expression was subsequently performed. The primary study endpoint was the correlation between microRNAs and MMP2, TIMP1/2 mRNA/protein expression., Results: We found a significant association between miR-133a and TIMP1 mRNA ( r  = 0.870, p  < 0.001), an inverse correlation between miR-143a and MMP2 protein expression ( r = -0.614, p  = 0.044) and a positive correlation between miR-133a and TIMP-2 protein expression ( r  = 0.583, p  = 0.036) at the greater curvature., Conclusion: Our findings indicate that aortic tissue microRNAs may reflect remodelling processes of the proximal aorta in BAV aortopathy. Specific aortic tissue microRNAs may exert their regulatory effects on the aortopathy through their impact on MMPs/TIMPs homeostasis at the level of the greater curvature.

Background: Bicuspid aortic valve is the most common congenital valvular heart defect in the general population. BAV is associated with significant morbidity due to valve failure, formation of thoracic aortic aneurysm, and increased risk of infective endocarditis and aortic dissection. Loss of function mutations in NOTCH1 (OMIM 190198) has previously been associated with congenital heart disease involving the aortic valve, left ventricle outflow tract, and mitral valve that segregates in affected pedigrees as an autosomal dominant trait with variable expressivity., Methods: We performed whole-exome sequencing in four members of a three-generational family (three affected and one unaffected subject) with clinical phenotypes including aortic valve stenosis, thoracic aortic aneurysm, and ventricular septal defect., Results: We identified 16 potentially damaging genetic variants (one stop variant, one splice variant, and 14 missense variants) cosegregating with the phenotype. Of these variants, the nonsense mutation (p.Tyr291*) in NOTCH1 was the most deleterious variant identified and the most likely variant causing the disease., Conclusion: Inactivating NOTCH1 mutations are a rare cause of familial heart disease involving predominantly left ventricular outflow tract lesions and characterized by the heterogeneity of clinical phenotype., (© 2020 The Authors. Molecular Genetics & Genomic Medicine published by Wiley Periodicals LLC.)

Background: Bicuspid aortic valve (BAV) is the most common cardiovascular malformation in adults, with a prevalence of 0.5%-2%. The prevalence of BAV in cohorts who were ascertained due to thoracic aortic aneurysms or acute aortic dissections (TAD) is as high as 20%. However, the contribution of causal BAV genes to TAD is not known. Therefore, we evaluated rare deleterious variants of GATA4, NOTCH1, SMAD6, or ROBO4 in patients with BAV who presented with TAD., Methods: Our cohort consisted of 487 probands with Heritable Thoracic Aortic Aneurysms or Dissections (HTAD, 12% BAV, 29% female) and 63 probands with Early onset complications of Bicuspid Aortic Valve disease (EBAV, 63% TAD, 34% female). After whole exome sequencing, we functionally annotated GATA4, NOTCH1, SMAD6, and ROBO4 variants and compared the prevalence of rare variants in these genes to controls without HTAD., Results: We identified 11 rare deleterious variants of GATA4, SMAD6, or ROBO4 in 12 (18%) EBAV cases. The burden of rare SMAD6 and GATA4 variants was significantly enriched in EBAV but not in HTAD cases, even among HTAD cases with BAV (p < .003)., Conclusion: Rare variants of NOTCH1, ROBO4, SMAD6, or GATA4 do not significantly contribute to BAV in cohorts with HTAD. We conclude that BAV patients who present with HTAD are a genetically distinct subgroup with implications for genetic testing and prognosis., (© 2020 The Authors. Molecular Genetics & Genomic Medicine published by Wiley Periodicals LLC.)

Patients with a congenital bicuspid aortic valve (BAV), a valve with two instead of three aortic leaflets, have an increased risk of developing thoracic aneurysms and aortic dissection. The mechanisms underlying BAV-associated aortopathy are poorly understood. This study examined BAV-associated aortopathy in Nos3 -/- mice, a model with congenital BAV formation. A combination of histological examination and in vivo ultrasound imaging was used to investigate aortic dilation and dissections in Nos3 -/- mice. Moreover, cell lineage analysis and single-cell RNA sequencing were used to observe the molecular anomalies within vascular smooth muscle cells (VSMCs) of Nos3 -/- mice. Spontaneous aortic dissections were found in ascending aortas located at the sinotubular junction in ∼13% of Nos3 -/- mice. Moreover, Nos3 -/- mice were prone to developing aortic dilations in the proximal and distal ascending aorta during early adulthood. Lower volumes of elastic fibres were found within vessel walls of the ascending aortas of Nos3 -/- mice, as well as incomplete coverage of the aortic inner media by neural crest cell (NCC)-derived VSMCs. VSMCs of Nos3 -/- mice showed downregulation of 15 genes, of which seven were associated with aortic aneurysms and dissections in the human population. Elastin mRNA was most markedly downregulated, followed by fibulin-5 expression, both primary components of elastic fibres. This study demonstrates that, in addition to congenital BAV formation, disrupted endothelial-mediated nitric oxide (NO) signalling in Nos3 -/- mice also causes aortic dilation and dissection, as a consequence of inhibited elastic fibre formation in VSMCs within the ascending aorta., Competing Interests: Competing interestsThe authors declare no competing or financial interests., (© 2020. Published by The Company of Biologists Ltd.)

One key risk factor of aortic valve stenosis in clinical practice is bicuspid aortic valve (BAV). Increasing evidence indicates that numerous microRNAs (miRs/miRNAs) are involved in BAV calcification via their target genes. miR‑330‑3p was found to be involved in the deterioration of BAV calcification by miR profiling in human calcified BAV and tricuspid aortic valve (TAV) tissues in the present study and the underlying mechanism was investigated. RNA sequencing was performed on four BAV and four TAV tissues from patients with aortic stenosis before these leaflets were examined for the expression levels of miR‑330‑3p and CREB‑binding protein (CREBBP) by reverse transcription‑PCR. The alteration of functional factors associated with calcification was also assessed by Western blotting and immunohistochemistry in human aortic tissue samples. The putative target of miR‑330‑3p was detected by dual‑luciferase assay in 293 cells. Furthermore, the influence of miR‑330‑3p expression on osteogenic progression was explored in cultured porcine valve interstitial cells (VICs). Rescue experiments of CRBBP were performed to confirm the influence of the miR‑330‑3p‑CREBBP pathway in the calcification progress in porcine VICs. RNA sequencing indicated distinct expression of miR‑330‑3p in human BAV tissues compared with TAV, which was then confirmed by PCR. CREBBP expression levels in human BAV and TAV leaflets also demonstrated the opposite alterations. This negative correlation was then confirmed in cultured porcine VICs. Under an osteogenic environment, cellular calcification was promoted in miR‑330‑3p‑overexpressed porcine VICs expressing higher bone morphogenetic protein 2, Runt‑related transcription factor 2, matrix metalloproteinase (MMP)‑2, MMP‑9 and collagen I compared with controls. Rescue experiments further confirmed that miR‑330‑3p played its role via targeting CREBBP in porcine VICs. Collectively, miR‑330‑3p was upregulated in calcified BAV compared with TAV. The upregulation of miR‑330‑3p promotes the calcification progress partially via targeting CREBBP.

Bicuspid aortic valve (BAV) is the most common human congenital cardiac malformation. Although the etiology is unknown for most patients, formation of the 2 main BAV anatomic types (A and B) has been shown to rely on distinct morphogenetic mechanisms. Animal models of BAV include 2 spontaneous hamster strains and 27 genetically modified mouse strains. To assess the value of these models for extrapolation to humans, we examined the aortic valve anatomy of 4340 hamsters and 1823 mice from 8 and 7 unmodified strains, respectively. In addition, we reviewed the literature describing BAV in nonhuman mammals. The incidences of BAV types A and B were 2.3% and 0.03% in control hamsters and 0% and 0.3% in control mice, respectively. Hamsters from the spontaneous model had BAV type A only, whereas mice from 2 of 27 genetically modified strains had BAV type A, 23 of 27 had BAV type B, and 2 of 27 had both BAV types. In both species, BAV incidence was dependent on genetic background. Unlike mice, hamsters had a wide spectrum of aortic valve morphologies. We showed interspecific differences in the occurrence of BAV between humans, hamsters, and mice that should be considered when studying aortic valve disease using animal models. Our results suggest that genetic modifiers play a significant role in both the morphology and incidence of BAV. We propose that mutations causing anomalies in specific cardiac morphogenetic processes or cell lineages may lead to BAV types A, B, or both, depending on additional genetic, environmental, and epigenetic factors.