Milewicz, Dianna M.

Background Bicuspid aortic valve (BAV) is the most common congenital heart defect in adults, often leading to complications such as thoracic aortic aneurysms and aortic stenosis. While BAV is frequently associated with 22q11.2 deletion syndrome (22q11.2DS), the contribution of rare copy number variants (CNVs) in this region to non-syndromic BAV is less clear. This study is aimed to assess the role of rare 22q11.2 CNVs in patients with early-onset BAV (EBAV) and to determine whether these variants are linked to an increased risk of complications. Methods Whole genome microarray genotyping was conducted on 272 patients with BAV with early onset valve or aortic disease (EBAV) and 272 biological relatives. CNVs were detected using three independent algorithms, focusing on the 22q11.2 region (18–24 Mb). CNV burden in the EBAV cohort was compared with unselected European ancestry controls. Results Rare duplications and deletions within the 22q11.2 region, particularly involving genes associated with cardiac development, were identified in 7.4% of EBAV probands. These CNVs were significantly enriched compared with the general population and segregated with BAV in families. Individuals carrying rare 22q11.2 CNVs had a higher prevalence of psychiatric diagnoses and learning difficulties, although they did not exhibit the typical features of 22q11.2DS. Importantly, these CNVs were associated with early onset or complex BAV cases, underscoring their potential clinical relevance. Conclusions Rare 22q11.2 CNVs play a role in non-syndromic BAV, particularly in cases with early onset or complex presentations. CNV screening could be considered as part of risk stratification for patients with BAV, helping to predict complications and guide management. Trial registration number NCT01823432 .

Abstract Moyamoya disease, a cerebrovascular disease leading to strokes in children and young adults, is characterized by progressive occlusion of the distal internal carotid arteries and the formation of collateral vessels. Altered genes play a prominent role in the aetiology of moyamoya disease, but a causative gene is not identified in the majority of cases. Exome sequencing data from 151 individuals from 84 unsolved families were analysed to identify further genes for moyamoya disease, then candidate genes assessed in additional cases (150 probands). Two families had the same rare variant in ANO1, which encodes a calcium-activated chloride channel, anoctamin-1. Haplotype analyses found the families were related, and ANO1 p.Met658Val segregated with moyamoya disease in the family with an LOD score of 3.3. Six additional ANO1 rare variants were identified in moyamoya disease families. The ANO1 rare variants were assessed using patch-clamp recordings, and the majority of variants, including ANO1 p.Met658Val, displayed increased sensitivity to intracellular Ca2+. Patients harbouring these gain-of-function ANO1 variants had classic features of moyamoya disease, but also had aneurysm, stenosis and/or occlusion in the posterior circulation. Our studies support that ANO1 gain-of-function pathogenic variants predispose to moyamoya disease and are associated with unique involvement of the posterior circulation.

Introduction: The prevalence of bicuspid aortic valves (BAV) is enriched thirty-fold in women with Turner Syndrome (TS) in comparison with the general population. Hypothesis: Common autosomal variants influence the development of BAV in TS women, who may be uniquely sensitized to these variants by the loss of one X chromosome. We sought to identify autosomal BAV susceptibility genes in a cohort of TS women (average age 30 years, 38% BAV, 18% coarctation). Methods: A total of 106 TS women of European ancestry with BAV and 173 TS women with tricuspid aortic valves were genotyped on Illumina Omni-Express arrays. Valve phenotypes were determined by independent review of echocardiograms from the enrolling sites. Tests of association were performed using logistic regression without adjustment for covariates and were summarized in a meta-analysis. Results: Xp dosage was inversely and quantitatively associated with BAV status (P=0.02). Large, recurrent copy number variants in 1p36.13, 3q29, 8p23.1 and 9p24.3 were significantly enriched in BAV cases. After exclusion of 26 outlier samples in multidimensional scaling analysis, there was no significant genomic inflation (lambda= 1.02). The strongest genome-wide association signals were observed in 1p36.23, 3q23, 12q21.2, 18q21 and 22q13.31, and did not overlap with previously reported loci for BAV. A total of 13 SNPs in 18q21 were positively associated with BAV (OR=2.5-4.3) with a minimum P value of 1x10-7. Replication of these regions in independent groups of cases is ongoing. Conclusion: Our results demonstrate that autosomal variants with large magnitudes of effect contribute to BAV in TS women, confirming our hypothesis, and provide evidence for gene-gene interactions in BAV formation.

Abstract 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.

Abstract This International evidence-based nomenclature and classification consensus on the congenital bicuspid aortic valve and its aortopathy recognizes 3 types of bicuspid aortic valve: 1. Fused type, with 3 phenotypes: right-left cusp fusion, right-non cusp fusion and left-non cusp fusion; 2. 2-sinus type with 2 phenotypes: Latero-lateral and antero-posterior; and 3. Partial-fusion or forme fruste. This consensus recognizes 3 bicuspid-aortopathy types: 1. Ascending phenotype; root phenotype; and 3. extended phenotypes.

Turner Syndrome (TS) is a developmental disorder caused by partial or complete loss of one sex chromosome. Bicuspid aortic valve and other left‐sided congenital heart lesions (LSL), including thoracic aortic aneurysms and acute aortic dissections, are 30–50 times more frequent in TS than in the general population. In 454 TS subjects, we found that LSL are significantly associated with reduced dosage of Xp genes and increased dosage of Xq genes. We also showed that genome‐wide copy number variation is increased in TS and identify a common copy number variant (CNV) in chromosome 12p13.31 that is associated with LSL with an odds ratio of 3.7. This CNV contains three protein‐coding genes (SLC2A3, SLC2A14, and NANOGP1) and was previously implicated in congenital heart defects in the 22q11 deletion syndrome. In addition, we identified a subset of rare and recurrent CNVs that are also enriched in non‐syndromic BAV cases. These observations support our hypothesis that X chromosome and autosomal variants affecting cardiac developmental genes may interact to cause the increased prevalence of LSL in TS. © 2016 Wiley Periodicals, Inc.

Background Intracranial aneurysms ( IAs ), abdominal aortic aneurysms ( AAAs ), and thoracic aortic aneurysms ( TAAs ) all have a familial predisposition. Given that aneurysm types are known to co‐occur, we hypothesized that there may be shared genetic risk factors for IAs , AAAs, and TAAs . Methods and Results We performed a mega‐analysis of 1000 Genomes Project‐imputed genome‐wide association study ( GWAS ) data of 4 previously published aneurysm cohorts: 2 IA cohorts (in total 1516 cases, 4305 controls), 1 AAA cohort (818 cases, 3004 controls), and 1 TAA cohort (760 cases, 2212 controls), and observed associations of 4 known IA , AAA , and/or TAA risk loci (9p21, 18q11, 15q21, and 2q33) with consistent effect directions in all 4 cohorts. We calculated polygenic scores based on IA ‐, AAA ‐, and TAA ‐associated SNP s and tested these scores for association to case‐control status in the other aneurysm cohorts; this revealed no shared polygenic effects. Similarly, linkage disequilibrium–score regression analyses did not show significant correlations between any pair of aneurysm subtypes. Last, we evaluated the evidence for 14 previously published aneurysm risk single‐nucleotide polymorphisms through collaboration in extended aneurysm cohorts, with a total of 6548 cases and 16 843 controls ( IA ) and 4391 cases and 37 904 controls ( AAA ), and found nominally significant associations for IA risk locus 18q11 near RBBP 8 to AAA (odds ratio [ OR ]=1.11; P =4.1×10 −5 ) and for TAA risk locus 15q21 near FBN 1 to AAA ( OR =1.07; P =1.1×10 −3 ). Conclusions Although there was no evidence for polygenic overlap between IAs , AAAs , and TAAs , we found nominally significant effects of two established risk loci for IAs and TAAs in AAAs . These two loci will require further replication.