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Left-ventricular outflow tract obstructions (LVOTO) encompass a wide spectrum of phenotypically heterogeneous heart malformations which frequently cluster in families. We performed family based whole-exome and targeted re-sequencing on 182 individuals from 51 families with multiple affected members. Central to our approach is the family unit which serves as a reference to identify causal genotype-phenotype correlations. Screening a multitude of 10 overlapping phenotypes revealed disease associated and co-segregating variants in 12 families. These rare or novel protein altering mutations cluster predominantly in genes (NOTCH1, ARHGAP31, MAML1, SMARCA4, JARID2, JAG1) along the Notch signaling cascade. This is in line with a significant enrichment (Wilcoxon, p< 0.05) of variants with a higher pathogenicity in the Notch signaling pathway in patients compared to controls. The significant enrichment of novel protein truncating and missense mutations in NOTCH1 highlights the allelic and phenotypic heterogeneity in our pediatric cohort. We identified novel co-segregating pathogenic mutations in NOTCH1 associated with left and right-sided cardiac malformations in three independent families with a total of 15 affected individuals. In summary, our results suggest that a small but highly pathogenic fraction of family specific mutations along the Notch cascade are a common cause of LVOTO.

BackgroundBicuspid aortic valve (BAV) is often associated with a concomitant aortopathy. However, few studies have evaluated the effect of the aortic valve (AV) phenotype on the rate of dilation of the aorta. This study aimed to compare the progression rate of aorta dimensions according to AV phenotype (BAV vs tricuspid AV (TAV)), fusion type and sex in patients with aortic stenosis (AS).Methods310 patients with AS (224 TAV and 86 BAV) recruited in the Metabolic Determinants of the Progression of Aortic Stenosis study (PROGRESSA, NCT01679431) were included in this analysis. Doppler echocardiography was performed annually to assess AS severity and measure ascending aorta (AA) dimensions. Baseline and last follow-up visit measurements were used to assess the annualised change.ResultsMedian AA annualised change was larger in BAV versus TAV (0.33±0.65 mm/year vs 0.21±0.56 mm/year, p=0.04). In the whole cohort, BAV phenotype and higher low-density lipoprotein (LDL) levels were significantly associated with fast progression of AA dilation in univariate analysis (OR 1.80, 95% CI 1.08 to 2.98, p=0.02; 1.37, 95% CI 1.04 to 1.80, p=0.03, respectively). AA dilation rate did not vary according to the BAV subtype (p=0.142). Predictors of AA progression rate were different between valve phenotypes, with higher apolipoprotein B/apolipoprotein A-I ratio, higher baseline peak aortic jet velocity (Vpeak) and smaller baseline AA diameter in the TAV cohort (all p<0.05) versus absence of hypertension, higher LDL levels and smaller baseline AA diameter in the BAV cohort (all p<0.02). In men, higher baseline Vpeak and smaller baseline AA (p<0.001) were independently associated with increased annualised AA dilation, while in women, higher LDL levels (p=0.026) were independently associated with faster AA dilation.ConclusionThis study suggests that BAV is associated with faster dilation of the AA. Predictors of AA dilation are different between valve phenotype and sex, with higher LDL levels being associated with faster AA dilation in BAV.

ObjectiveTo evaluate the effect of age and aortic valve anatomy (tricuspid (TAV) vs bicuspid (BAV) aortic valve) on the relationship between the aortic valve calcification (AVC) and the haemodynamic parameters of aortic stenosis (AS) severity.MethodsTwo hundred patients with AS and preserved left ventricular ejection fraction were prospectively recruited in the PROGRESSA (Metabolic Determinants of the Progression of Aortic Stenosis) study and underwent a comprehensive Doppler echocardiography and multidetector CT (MDCT). Mean transvalvular gradient (MG) measured by Doppler echocardiography was used to assess AS haemodynamic severity and AVC was evaluated by MDCT using the Agatston method and indexed to the left ventricular outflow tract area to obtain AVC density (AVCd). All analyses were adjusted for sex.ResultsThirty-nine patients had a BAV and 161 a TAV. Median age was 51 and 72 years for BAV and TAV patients, respectively. There was a modest correlation between MG and AVCd (ρ=0.51, p<0.0001) in the whole cohort. After dichotomisation for valve anatomy, there was a good correlation between AVCd and MG in the TAV group (ρ=0.61, p<0.0001) but weak correlation in the BAV group (ρ=0.32, p=0.046). In the TAV group, the strength of the AVCd–MG correlation was similar in younger (<72 years old; ρ=0.59, p<0.0001) versus older (≥72 years old; ρ=0.61, p<0.0001) patients. In the BAV group, there was no correlation between AVCd and MG in younger patients (<51 years old; ρ=0.12, p=0.65), whereas there was a good correlation in older patients (≥51 years old; ρ=0.55, p=0.009). AVCd (p=0.005) and age (p=0.02) were both independent determinants of MG in BAV patients while AVCd (p<0.0001) was the only independent determinant of MG in TAV patients.ConclusionsIn patients with TAV as well as in older patients with BAV, AVCd appears to be the main factor significantly associated with the haemodynamic severity of AS and so it may be used to corroborate AS severity in case of uncertain or discordant findings at echocardiography. However, among younger patients with BAV, some may have a haemodynamically significant stenosis with minimal AVCd. The results of MDCT AVCd should thus be interpreted cautiously in this subset of patients.Trial registration numberNCT01679431; Pre-results.

Gregor Andelfinger and colleagues identify mutations in SGOL1 that cause a novel cohesinopathy characterized by chronic atrial and intestinal dysrhythmia, termed CAID syndrome. SGOL1 encodes a component of the cohesin complex, suggesting that cardiac and gut rhythm are regulated by this complex. The pacemaking activity of specialized tissues in the heart and gut results in lifelong rhythmic contractions. Here we describe a new syndrome characterized by Chronic Atrial and Intestinal Dysrhythmia, termed CAID syndrome, in 16 French Canadians and 1 Swede. We show that a single shared homozygous founder mutation in SGOL1 , a component of the cohesin complex, causes CAID syndrome. Cultured dermal fibroblasts from affected individuals showed accelerated cell cycle progression, a higher rate of senescence and enhanced activation of TGF-β signaling. Karyotypes showed the typical railroad appearance of a centromeric cohesion defect. Tissues derived from affected individuals displayed pathological changes in both the enteric nervous system and smooth muscle. Morpholino-induced knockdown of sgol1 in zebrafish recapitulated the abnormalities seen in humans with CAID syndrome. Our findings identify CAID syndrome as a novel generalized dysrhythmia, suggesting a new role for SGOL1 and the cohesin complex in mediating the integrity of human cardiac and gut rhythm.

Left-sided congenital heart disease (CHD) encompasses a spectrum of malformations that range from bicuspid aortic valve to hypoplastic left heart syndrome. It contributes significantly to infant mortality and has serious implications in adult cardiology. Although left-sided CHD is known to be highly heritable, the underlying genetic determinants are largely unidentified. In this study, we sought to determine the impact of structural genomic variation on left-sided CHD and compared multiplex families (464 individuals with 174 affecteds (37.5%) in 59 multiplex families and 8 trios) to 1,582 well-phenotyped controls. 73 unique inherited or de novo CNVs in 54 individuals were identified in the left-sided CHD cohort. After stringent filtering, our gene inventory reveals 25 new candidates for LS-CHD pathogenesis, such as SMC1A, MFAP4, and CTHRC1, and overlaps with several known syndromic loci. Conservative estimation examining the overlap of the prioritized gene content with CNVs present only in affected individuals in our cohort implies a strong effect for unique CNVs in at least 10% of left-sided CHD cases. Enrichment testing of gene content in all identified CNVs showed a significant association with angiogenesis. In this first family-based CNV study of left-sided CHD, we found that both co-segregating and de novo events associate with disease in a complex fashion at structural genomic level. Often viewed as an anatomically circumscript disease, a subset of left-sided CHD may in fact reflect more general genetic perturbations of angiogenesis and/or vascular biology.

ObjectiveThe aim of this study was to compare the prevalence of left ventricle non-compaction (LVNC) criteria (or hypertrabeculation) in a cohort of patients with bicuspid aortic valve (BAV) and healthy control subjects (CTL) without cardiovascular disease using cardiovascular MR (CMR).Methods79 patients with BAV and 85 CTL with tricuspid aortic valve and free of known cardiovascular disease underwent CMR to evaluate the presence of LVNC criteria. The left ventricle was assessed at end-systole and end-diastole, in the short-axis, two-chamber and four-chamber views and divided into the 16 standardised myocardial segments. LVNC was assessed using the non-compacted/compacted (NC/C) myocardium ratio and was considered to be present if at least one of the myocardial segments had a NC/C ratio superior to the cut-off values defined in previous studies: Jenni et al (>2.0 end-systole); Petersen et al (>2.3 end-diastole); or Fazio et al (>2.5 end-diastole).Results15 CTL (17.6%) vs 8 BAV (10.1%) fulfilled Jenni et al’s criterion; 69 CTL (81.2%) vs 49 BAV (62.0%) fulfilled Petersen et al’s criterion; and 66 CTL (77.6%) vs 43 BAV (54.4%) fulfilled Fazio et al’s criterion. Petersen et al and Fazio et al’s LVNC criteria were met more often by CTL (p=0.006 and p=0.002, respectively) than patients with BAV, whereas this difference was not statistically significant according to Jenni et al’s criterion (p=0.17). In multivariable analyses, after adjusting for age, sex, the presence of significant valve dysfunction (>mild stenosis or >mild regurgitation), indexed LV mass, indexed LV end-diastolic volume and LV ejection fraction, BAV was not associated with any of the three LVNC criteria.ConclusionPatients with BAV do not harbour more LVNC than the general population and there is no evidence that they are at higher risk for the development of LVNC cardiomyopathy.

Congenital cardiac disease is the most common malformation, and a substantial source of mortality and morbidity in children and young adults. A role for genetic factors is recognised for these malformations, but overall few predisposing loci have been identified. Here we report the rationale, design, and first results of a multi-institutional congenital cardiac disease cohort, assembled mainly from the French-Canadian population of the province of Quebec and centred on families with multiple affected members afflicted by cardiac malformations. Families were recruited into the study, phenotyped and sampled for DNA in cardiology clinics over the first 3 years of enrolment. We performed segregation analysis and linkage simulations in the subgroup of families with left ventricular outflow tract obstruction (LVOTO). A total of 1603 participants from 300 families were recruited, with 169 out of 300 (56.3%) families having more than one affected member. For the LVOTO group, we estimate heritability to be 0.46-0.52 in our cohort. Simulation analysis demonstrated sufficient power to carry out linkage analyses, with an expected mean log-of-odds (LOD) score of 3.8 in 67 pedigrees with LVOTO. We show feasibility and usefulness of a population-based biobank for genetic investigations into the causes of congenital cardiac disease. Heritability of LVOTO is high and could be accounted for by multiple loci. This platform is ideally suited for multiple analysis approaches, including linkage analysis and novel gene sequencing approaches, and will allow to establish segregation of risk alleles at family and population levels.

We describe a patient in whom we found dual orifices in a straddling and overriding tricuspid valve, with two normally sized ventricles and a cleft in the mitral valve. The patient underwent successful surgical repair. We discuss the concept of “double-orifice right atrium”, as well as the need to differentiate the isolated cleft of the morphologically mitral valve from the zone of apposition between the left ventricular components of the bridging leaflets seen in the setting of atrioventricular septal defect with common atrioventricular junction. We emphasise the unusual association of these abnormalities of the right and left atrioventricular valves in patients with separate atrioventricular junctions.

Acute myopathy of intensive care has been described infrequently in children and never after organ transplantation. We report a case of acute myopathy of intensive care in a child after heart transplantation. An 11-yr-old girl, with no previous medical history, developed acute cardiomyopathy leading to cardiac shock. Family history revealed four cases of unidentified myopathy and/or cardiomyopathy. Preoperatively, while muscle biopsy was near normal, myocardial biopsy revealed non specific mitochondrial disorders. A few days after heart transplantation, she developed acute hypotonia and flaccid quadriplegia, consistent with the diagnosis of acute myopathy of intensive care. Nerve conduction studies were normal, electromyography showed myopathic changes and a new muscle biopsy from quadriceps femoris showed severe loss of myosin filaments and ATPase activity in type 2 fibres. A large laboratory screening failed to demonstrate a metabolic disease or a known myopathy. Muscle strength recovered progressively in three weeks allowing home discharge. A few months later, she was free of symptoms and muscle biopsy showed full histopathological recovery. Acute myopathy of intensive care can occur in children after heart transplantation. It should be suspected in the presence of muscle weakness and difficulty in weaning from ventilatory support. Electromyography confirmed a myogenic process and muscle biopsy allowed diagnosis. Full clinical and histopathological recovery usually occur within three weeks.