Project description:Supravalvular aortic stenosis (SVAS) is caused by mutations in the elastin (ELN) gene and is characterized by abnormal proliferation of vascular smooth muscle cells (SMCs) that can lead to narrowing or blockage of the ascending aorta and other arterial vessels. Having patient-specific SMCs available may facilitate the study of disease mechanisms and development of novel therapeutic interventions.Here, we report the development of a human induced pluripotent stem cell (iPSC) line from a patient with SVAS caused by the premature termination in exon 10 of the ELN gene resulting from an exon 9 four-nucleotide insertion. We showed that SVAS iPSC-derived SMCs (iPSC-SMCs) had significantly fewer organized networks of smooth muscle ?-actin filament bundles, a hallmark of mature contractile SMCs, compared with control iPSC-SMCs. The addition of elastin recombinant protein or enhancement of small GTPase RhoA signaling was able to rescue the formation of smooth muscle ?-actin filament bundles in SVAS iPSC-SMCs. Cell counts and BrdU analysis revealed a significantly higher proliferation rate in SVAS iPSC-SMCs than control iPSC-SMCs. Furthermore, SVAS iPSC-SMCs migrated at a markedly higher rate to the chemotactic agent platelet-derived growth factor compared with the control iPSC-SMCs. We also provided evidence that elevated activity of extracellular signal-regulated kinase 1/2 is required for hyperproliferation of SVAS iPSC-SMCs. The phenotype was confirmed in iPSC-SMCs generated from a patient with deletion of elastin owing to Williams-Beuren syndrome.SVAS iPSC-SMCs recapitulate key pathological features of patients with SVAS and may provide a promising strategy to study disease mechanisms and to develop novel therapies.
Project description:A 20 year old female was referred to us for evaluation of effort dyspnoea of NYHA class II with feeble left common carotid, left brachial and left radial artery as compared to other sides. Detail evaluation with two dimensional (2D) transthoracic echocardiographic, 2D transesophageal echocardiography and multidetector computed tomography (MDCT) delineated Cleft AML and diffuse type of supravalvular aortic stenosis. To the best of our knowledge, no such case have been described in the literature where these anomalies co-existed in the same patient.
Project description:Supravalvular aortic stenosis (SVAS) is an inherited vascular disease that can cause heart failure and death. SVAS can be inherited as an autosomal dominant trait or as part of a developmental disorder, Williams syndrome (WS). In recent studies we presented evidence suggesting that a translocation disrupting the elastin gene caused SVAS in one family while deletions involving the entire elastin locus caused WS. In this study, pulsed-field, PCR, and Southern analyses showed that a 100-kb deletion of the 3' end of the elastin gene cosegregated with the disease in another SVAS family. DNA sequence analysis localized the breakpoint between elastin exons 27 and 28, the same region disrupted by the SVAS-associated translocation. These data indicate that mutations in the elastin gene cause SVAS and suggest that elastin exons 28-36 may encode critical domains for vascular development.
Project description:This case report describes the clinical presentation, the necropsy findings, and genetic results of a 13-year-old Warmblood mare presented with colic and a bilaterally loud, holosystolic murmur. Echocardiographic examination revealed the presence of a thoracic aortic aneurysm, an aortic pseudoaneurysm, a periaortic hematoma (circumferential cuffing by perivascular hemorrhage), and aortopulmonary fistulation. A supravalvular aortic stenosis (SVAS) was visible during echocardiography. Necropsy confirmed that the thoracic aortic aneurysm had ruptured and connected to the pseudoaneurysm, which fistulated into the pulmonary artery. Histologically, the aneurysm wall revealed chronic lesions such as fibrosis, mucin depositions, mineralizations, and elastin fragmentation. The mid abdominal aorta showed lesions suggestive of a systemic elastin arteriopathy. Molecular analysis, however, could not attribute this disease to a variant in the elastin gene, the most common causative gene for SVAS. To the authors' knowledge, this case report describes a case of aortopulmonary fistulation in a Warmblood horse associated with the presence of SVAS and an aortic aneurysm.
Project description:Pathogenic germline mutations in ELN can be detected in patients with supravalvular aortic stenosis. The mutation might occur de novo or be inherited following an autosomal dominant pattern of inheritance. In this report we describe a three-generation family suffering from supravalvular aortic stenosis, various other arterial stenoses, sudden death, and intracranial aneurysms. A frameshift mutation in exon 12, not described before, was detected in the affected family members. This report emphasises the importance of family history, genetic counselling, and demonstrates the great variability in the phenotype within a single SVAS family.
Project description:Atrial septal defect is a persistent interatrial communication. It is the second most common congenital heart defect and is detected in 1:1500 live births. Clinical course is variable and depends on the size of the malformation. Clinical diagnosis is based on patient history, physical and instrumental examination. Atrial septal defect is frequently sporadic, but familial cases have been reported. The disease has autosomal dominant inheritance with reduced penetrance, variable expressivity and genetic heterogeneity. Supravalvular aortic stenosis is a congenital narrowing of the lumen of the ascending aorta. It has an incidence of 1:20000 newborns and a prevalence of 1:7500. Clinical diagnosis is based on patient history, physical and instrumental examination. Supravalvular aortic stenosis is either sporadic or familial and has autosomal dominant inheritance with reduced penetrance and variable expressivity. It is associated with mutations in the ELN gene. Syndromes predisposing to aneurysm of large vessels is a group of inherited disorders that may affect different segments of the aorta. They may occur in isolation or associated with other genetic syndromes. Clinical symptoms are highly variable. Familial thoracic aortic aneurysm and dissection accounts for ~20% of all cases of aneurysms. The exact prevalence is unknown. Clinical diagnosis is based on medical history, physical and instrumental examination. Genetic testing is useful for confirming diagnosis of these syndromes and for differential diagnosis, recurrence risk evaluation and prenatal diagnosis in families with a known mutation. Most syndromes predisposing to aneurysm of large vessels have autosomal dominant inheritance with reduced penetrance and variable expressivity.
Project description:BACKGROUND:Supravalvular aortic stenosis (SVAS) is one of the congenital cardiovascular diseases characterized by stenosis of the aorta. The stenotic lesions occur anywhere above the aortic valve in the aortic tree as well as pulmonary arteries and eventually leads to circulatory failure. The disease gene has been identified on the elastin gene (ELN) and two types of SVAS have been categorized; a familial type and an isolated type with the de novo mutation. METHODS:Fluorescent In situ hybridization (FISH) analysis and gene sequencing were performed in a two-generation family in which severe form of SVAS was diagnosed. RESULTS:None of the patients tested showed microdeletion of ELN, LIMK1, and D7S613. A novel nonsense mutation of ELN (c.160G>T (p.(Gly54*)), RNA not analyzed) was found in exon 3 in three members; two of them died suddenly due to rapid progression of SVAS with possible arrhythmia in early infancy. A point mutation in the 5' untranslated region, which was previously suggested to be associated with SVAS, did not co-segregate with the SVAS phenotype and found to be SNPs. CONCLUSION:Our report shows a broad spectrum of clinical features in family members sharing the identical mutations, suggesting a potential contribution of modifier gene(s) or interactions with environmental factors.
Project description:To elucidate the pathomechanism leading to obstructive vascular disease in patients with elastin deficiency, we compared both elastogenesis and proliferation rate of cultured aortic smooth-muscle cells (SMCs) and skin fibroblasts from five healthy control subjects, four patients with isolated supravalvular aortic stenosis (SVAS), and five patients with Williams-Beuren syndrome (WBS). Mutations were determined in each patient with SVAS and in each patient with WBS. Three mutations found in patients with SVAS were shown to result in null alleles. RNA blot hybridization, immunostaining, and metabolic labeling experiments demonstrated that SVAS cells and WBS cells have reduced elastin mRNA levels and that they consequently deposit low amounts of insoluble elastin. Although SVAS cells laid down approximately 50% of the elastin made by normal cells, WBS cells deposited only 15% of the elastin made by normal cells. The observed difference in elastin-gene expression was not caused by a difference in the stability of elastin mRNA in SVAS cells compared with WBS cells, but it did indicate that gene-interaction effects may contribute to the complex phenotype observed in patients with WBS. Abnormally low levels of elastin deposition in SVAS cells and in WBS cells were found to coincide with an increase in proliferation rate, which could be reversed by addition of exogenous insoluble elastin. We conclude that insoluble elastin is an important regulator of cellular proliferation. Thus, the reduced net deposition of insoluble elastin in arterial walls of patients with either SVAS or WBS leads to the increased proliferation of arterial SMCs. This results in the formation of multilayer thickening of the tunica media of large arteries and, consequently, in the development of hyperplastic intimal lesions leading to segmental arterial occlusion.
Project description:Apparently, balanced chromosomal rearrangements usually have no phenotypic consequences for the carrier. However, in some cases, they may be associated with an abnormal phenotype. We report herein the case of a 4-year-old boy presenting with clinically isolated supravalvular aortic stenosis (SVAS). No chromosomal imbalance was detected by array CGH. The karyotype showed a balanced paracentric chromosome 7 inversion. Breakpoint characterization using paired-end whole-genome sequencing (WGS) revealed an ELN gene disruption in intron 1, accounting for the phenotype. Family study showed that the inversion was inherited, with incomplete penetrance. To our knowledge, this is the first case of a disruption of the ELN gene characterized by WGS. It contributes to refine the genotype-phenotype correlation in ELN disruption. Although this disruption is a rare etiology of SVAS, it cannot be detected by the diagnostic tests usually performed, such as array CGH or sequencing methods (Sanger, panel, or exome sequencing). With the future perspective of WGS as a diagnostic tool, it will be important to include a structural variation analysis in order to detect balanced rearrangements and gene disruption.