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Crofton AE, Kovacs SL, Stern JA. Subvalvular Aortic Stenosis: Learning From Human and Canine Clinical Research. Cardiol Res 2023; 14:319-333. [PMID: 37936623 PMCID: PMC10627371 DOI: 10.14740/cr1547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 10/03/2023] [Indexed: 11/09/2023] Open
Abstract
Subvalvular aortic stenosis (SAS) is the most common congenital heart disease (CHD) in dogs and is also prevalent in human children. A fibrous ridge below the aortic valve narrows the left ventricular outflow tract (LVOT) and increases blood flow velocity, leading to devastating side effects in diseased patients. Due to the similarities in presentation, anatomy, pathophysiology, cardiac development, genomics, and environment between humans and dogs, canine SAS patients represent a critical translational model of human SAS. Potential adverse outcomes of SAS include arrhythmias, left-sided congestive heart failure, endocarditis, exercise intolerance, syncope, and sudden cardiac death. The greatest divergence between canine and human SAS clinical research has been the standard of care regarding treatment of these outcomes, with pharmacological intervention dominating best practices in veterinary medicine and surgical intervention comprising the standard practice for human SAS patients. Regardless of the species, the field has yet to identify a treatment option to prevent disease progression or permanently remove the fibrous ridge, but historical leaps in SAS research support a continued translational approach as the most promising method for achieving this goal.
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Affiliation(s)
- Amanda E. Crofton
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California Davis, Davis, CA 95616, USA
| | - Samantha L. Kovacs
- Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California Davis, Davis, CA 95616, USA
| | - Joshua A. Stern
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27607, USA
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Papakonstantinou NA, Kanakis MA, Bobos D, Giannopoulos NM. Congenital, acquired, or both? The only two congenitally based, acquired heart diseases. J Card Surg 2021; 36:2850-2856. [PMID: 33908651 DOI: 10.1111/jocs.15588] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 04/14/2021] [Accepted: 04/16/2021] [Indexed: 11/28/2022]
Abstract
Discrete subaortic stenosis (DSS) is a type of left ventricular outflow tract obstruction whereas double-chambered right ventricle is a form of right ventricular outflow tract obstruction. Both of these cardiac malformations share lots of similar characteristics which classify them as acquired developmental heart diseases despite their congenital anatomical substrate. Both of them are frequently associated to ventricular septal defects. The initial stimulus in their pathogenetic process is anatomical abnormalities or variations. Subsequently, a hemodynamic process is triggered finally leading to an abnormal subaortic fibroproliferative process with regard to DSS or to hypertrophy of ectopic muscles as far as double-chambered right ventricle is concerned. In many cases, these pathologies are developed secondarily to surgical management of other congenital or acquired heart defects. Moreover, high recurrence rates after initial successful surgical therapy, particularly regarding DSS, have been described. Finally, an interesting coexistence of DSS and double-chambered aortic ventricle has also been reported in some cases.
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Affiliation(s)
| | - Meletios A Kanakis
- Department of Pediatric and Congenital Heart Surgery, Onassis Cardiac Surgery Center, Athens, Greece
| | - Dimitrios Bobos
- Department of Pediatric and Congenital Heart Surgery, Onassis Cardiac Surgery Center, Athens, Greece
| | - Nicholas M Giannopoulos
- Department of Pediatric and Congenital Heart Surgery, Onassis Cardiac Surgery Center, Athens, Greece
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3
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Abstract
Congenital heart disease is the most common congenital defect observed in newborns. Within the spectrum of congenital heart disease are left‐sided obstructive lesions (LSOLs), which include hypoplastic left heart syndrome, aortic stenosis, bicuspid aortic valve, coarctation of the aorta, and interrupted aortic arch. These defects can arise in isolation or as a component of a defined syndrome; however, nonsyndromic defects are often observed in multiple family members and associated with high sibling recurrence risk. This clear evidence for a heritable basis has driven a lengthy search for disease‐causing variants that has uncovered both rare and common variants in genes that, when perturbed in cardiac development, can result in LSOLs. Despite advancements in genetic sequencing platforms and broadening use of exome sequencing, the currently accepted LSOL‐associated genes explain only 10% to 20% of patients. Further, the combinatorial effects of common and rare variants as a cause of LSOLs are emerging. In this review, we highlight the genes and variants associated with the different LSOLs and discuss the strengths and weaknesses of the present genetic associations. Furthermore, we discuss the research avenues needed to bridge the gaps in our current understanding of the genetic basis of nonsyndromic congenital heart disease.
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Affiliation(s)
- Lauren E Parker
- Division of Cardiology Department of Pediatrics Duke University School of Medicine Durham NC
| | - Andrew P Landstrom
- Division of Cardiology Department of Pediatrics Duke University School of Medicine Durham NC.,Department of Cell Biology Duke University School of Medicine Durham NC
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Abushaban L, Uthaman B, Selvan JP, Al Qbandi M, Sharma PN, Mariappa TV. Long-term follow-up and outcomes of discrete subaortic stenosis resection in children. Ann Pediatr Cardiol 2019; 12:212-219. [PMID: 31516277 PMCID: PMC6716322 DOI: 10.4103/apc.apc_120_18] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Background Studies of long-term outcomes of discrete subaortic stenosis (DSS) are rare. Therefore, we reviewed the long-term outcomes of subaortic membrane resection in children with isolated DSS over 16 years from a single institution. Materials and Methods We retrospectively reviewed the records of patients (n = 27) who underwent resection of DSS between 2000 and 2017. Patients with major concomitant intracardiac anomalies were excluded. Indications for surgery were mean left ventricular outflow tract (LVOT), Doppler gradient >30 mmHg, and/or progressive aortic insufficiency. Results The mean age at diagnosis was 3.77 ± 3.49 years (range, 0.25-13 years) and the mean age at surgery was 6.36 ± 3.69 years (range, 1-13 years). All patients underwent resection of subaortic membrane. The mean LVOT Doppler gradient decreased from 40.52 ± 11.41 mmHg preoperatively to 8.48 ± 5.06 mmHg postoperatively (P < 0.001). The peak instantaneous LVOT Doppler gradient decreased from 75.41 ± 15.22 mmHg preoperatively to 18.11 ± 11.44 mmHg postoperatively (P < 0.001). At the latest follow-up, the peak gradient was 17.63 ± 8.93 mmHg. The mean follow-up was 7.47 ± 3.53 years (median 6.33 years; range 2.67-16 years). There was no operative mortality or late mortality. Recurrence of subaortic membrane occurred in 7 (25.92%, 7/27) patients who underwent primary DSS operation. Four (14.81%, 4/27) patients required reoperation for DSS recurrence at a median time of 4.8 years (3.1-9.1 years) after the initial repair. Risk factors for reoperation were age <6 years at initial repair. Eighteen (66.66%, 18/27) patients had AI preoperatively and progression of AI occurred in 70.37% (19/27). This included 4 (22.22%, 4/18) patients who had worsening of their preoperative AI. Short valve-to-membrane distance was found to be prognostically unfavorable. One (3.7%, 1/27) patient had an iatrogenic ventricular septal defect, and 2 (7.4%, 2/27) patients had complete AV block following membrane resection. Conclusions Resection of subaortic membrane in children is associated with low mortality. Higher LVOT gradient, younger age at initial repair, and shorter valve-to-membrane distance were found to be associated with adverse outcome. Recurrence and reoperation rates are high, and progression of aortic insufficiency following subaortic membrane resection is common. Therefore, these patients warrant close follow-up into adult life.
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Affiliation(s)
- Lulu Abushaban
- Department of Pediatrics, Chest Diseases Hospital, Kuwait City, Kuwait.,Faculty of Medicine, Kuwait University, Kuwait City, Kuwait
| | - Babu Uthaman
- Department of Pediatrics, Chest Diseases Hospital, Kuwait City, Kuwait.,Faculty of Medicine, Kuwait University, Kuwait City, Kuwait
| | - John Puthur Selvan
- Department of Pediatric Cardiology, Ministry of Health, Chest Diseases Hospital, Kuwait City, Kuwait
| | - Mustafa Al Qbandi
- Department of Pediatric Cardiology, Ministry of Health, Chest Diseases Hospital, Kuwait City, Kuwait
| | - Prem N Sharma
- Health Sciences Center, Faculty of Medicine, Kuwait University, Kuwait City, Kuwait
| | - Thinakar Vel Mariappa
- Department of Pediatric Cardiology, Ministry of Health, Chest Diseases Hospital, Kuwait City, Kuwait
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5
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Massé DD, Shar JA, Brown KN, Keswani SG, Grande-Allen KJ, Sucosky P. Discrete Subaortic Stenosis: Perspective Roadmap to a Complex Disease. Front Cardiovasc Med 2018; 5:122. [PMID: 30320123 PMCID: PMC6166095 DOI: 10.3389/fcvm.2018.00122] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 08/17/2018] [Indexed: 12/13/2022] Open
Abstract
Discrete subaortic stenosis (DSS) is a congenital heart disease that results in the formation of a fibro-membranous tissue, causing an increased pressure gradient in the left ventricular outflow tract (LVOT). While surgical resection of the membrane has shown some success in eliminating the obstruction, it poses significant risks associated with anesthesia, sternotomy, and heart bypass, and it remains associated with a high rate of recurrence. Although a genetic etiology had been initially proposed, the association between DSS and left ventricle (LV) geometrical abnormalities has provided more support to a hemodynamic etiology by which congenital or post-surgical LVOT geometric derangements could generate abnormal shear forces on the septal wall, triggering in turn a fibrotic response. Validating this hypothetical etiology and understanding the mechanobiological processes by which altered shear forces induce fibrosis in the LVOT are major knowledge gaps. This perspective paper describes the current state of knowledge of DSS, articulates the research needs to yield mechanistic insights into a significant pathologic process that is poorly understood, and proposes several strategies aimed at elucidating the potential mechanobiological synergies responsible for DSS pathogenesis. The proposed roadmap has the potential to improve DSS management by identifying early targets for prevention of the fibrotic lesion, and may also prove beneficial in other fibrotic cardiovascular diseases associated with altered flow.
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Affiliation(s)
- Danielle D Massé
- Department of Mechanical and Materials Engineering, Wright State University, Dayton, OH, United States
| | - Jason A Shar
- Department of Mechanical and Materials Engineering, Wright State University, Dayton, OH, United States
| | - Kathleen N Brown
- Department of Bioengineering, Rice University, Houston, TX, United States
| | - Sundeep G Keswani
- Division of Pediatric Surgery, Texas Children's Hospital, Houston, TX, United States.,Department of Surgery, Baylor College of Medicine, Houston, TX, United States
| | | | - Philippe Sucosky
- Department of Mechanical and Materials Engineering, Wright State University, Dayton, OH, United States
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Abstract
Myocardial bridging is usually seen in the setting of hypertrophic cardiomyopathy or left ventricular hypertrophy. It is rarely reported in an asymptomatic patient with an otherwise structurally normal heart. Familial subaortic stenosis is also a rare entity, and its mode of inheritance is still unknown. Here, we described the case of a 13-year-old asymptomatic girl with a positive family history of sudden cardiac death and subaortic stenosis who was diagnosed with severe myocardial bridging concomitant with familial subaortic stenosis.
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8
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Weymann A, Schmack B, Rosendal C, Karck M, Szabó G. Surgical management of subaortic stenosis. Ann Thorac Cardiovasc Surg 2012. [PMID: 23196660 DOI: 10.5761/atcs.cr.12.01966] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
A 63-year-old male patient with subaortic stenosis (Pmax 105 mmHg, Pmean 55 mmHg) and an aneurysm of the ascending aorta was referred to our hospital due to progressive angina pectoris. Transesophageal echocardiography demonstrated high and turbulent subaortic flow velocities. A calcified subaortic membrane was identified. The membrane was removed and the aneurysm was treated with a Bentall procedure. The patient recovered smoothly from surgery and was doing well 6 months after discharge.
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Affiliation(s)
- Alexander Weymann
- Department of Cardiac Surgery, Heart Center-University of Heidelberg, Heidelberg, Germany
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9
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Lopes R, Lourenço P, Gonçalves A, Cruz C, Maciel MJ. The Natural History of Congenital Subaortic Stenosis. CONGENIT HEART DIS 2011; 6:417-23. [DOI: 10.1111/j.1747-0803.2011.00550.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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10
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Abstract
Discrete subaortic stenosis (DSS) accounts for 8 to 20% of all cases of congenital left ventricular outflow tract obstruction. There have been few scattered reports of left ventricular obstructive lesions occurring in immediate family members of patients with DSS. This is a report of four cases of DSS in one family: one brother with a fibrous ring, and two sisters and the son of one of the sisters with a fibrous membrane. The occurrence of multiple cases of DSS in this family suggests an autosomal dominant mode of inheritance.
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Affiliation(s)
- A A Petsas
- Cardiovascular Diagnostic Center, Nicosia, Cyprus
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11
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Piacentini G, Marino B, Digilio MC. Familial recurrence of discrete membranous subaortic stenosis. J Thorac Cardiovasc Surg 2007; 134:818-9; author reply 819. [PMID: 17723851 DOI: 10.1016/j.jtcvs.2007.01.095] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2007] [Accepted: 01/30/2007] [Indexed: 10/22/2022]
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12
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Fatimi SH, Ahmad U, Javed MA, Shamim S, Ahmad R. Familial membranous subaortic stenosis: review of familial inheritance patterns and a case report. J Thorac Cardiovasc Surg 2007; 132:1484-6. [PMID: 17140990 DOI: 10.1016/j.jtcvs.2006.08.034] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2006] [Accepted: 08/28/2006] [Indexed: 11/23/2022]
Affiliation(s)
- Saulat H Fatimi
- Department of Surgery, Division of Cardiothoracic Surgery, Aga Khan University, Karachi, Pakistan
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Freedom RM, Yoo SJ, Russell J, Perrin D, Williams WG. Thoughts about fixed subaortic stenosis in man and dog. Cardiol Young 2005; 15:186-205. [PMID: 15845164 DOI: 10.1017/s1047951105000399] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Robert M Freedom
- Department of Paediatrics, Division of Cardiology, The Hospital for Sick Children, University of Toronto, Tornto M5G 1X8, Canada.
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14
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Abstract
The discrete form of subaortic stenosis is thought to be an acquired lesion, the aetiology of which may be a combination of factors which include an underlying genetic predisposition, turbulence in the left ventricular outflow tract, and various geometric and anatomical variations of the left ventricular outflow tract. A review of hypotheses relating to its aetiology is provided
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Affiliation(s)
- A M Cilliers
- Division of Paediatric Cardiology, Department of Paediatrics and Child Health, Chris Hani Baragwanath Hospital, University of the Witwatersrand, Johannesburg, South Africa.
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Abid A, Denguir R, Chihaoui M, Khayati A, Abid F. [Role of surgery in subaortic stenosis. Report of 56 cases]. Ann Cardiol Angeiol (Paris) 2001; 50:261-8. [PMID: 12555585 DOI: 10.1016/s0003-3928(01)00028-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/20/2023]
Abstract
INTRODUCTION Subaortic stenosis is a rare congenital heart disease defined as a left ventricular outflow tract obstruction. We reviewed our surgical experience in this cardiac disease with particularly attention to the different anatomical types of the obstruction. PATIENTS AND METHODS From January 1987 to December 1998, 56 patients with a mean age of 12.4 years underwent surgical treatment of subaortic stenosis in our Institution. The diagnosis included: subaortic membrane in 44 cases, fibromuscular process in seven and tunnel like hypertrophy in five. RESULTS There were two hospital deaths (2/56 = 3.5%) and three patients presented postoperative heart block. The first postoperative echocardiographic control showed a mean fall in left ventricleaorta gradient of 78%. In a mean follow-up of 36 months, there were no deaths. All patients periodically controlled, showed an echocardiographic progression of the gradient and it was not related to the different anatomical types of the obstruction. There were no signs of aortic insufficiency progression. CONCLUSION We can affirm that the surgical treatment of the subaortic obstruction is simple and safe. The medium and long-term progression toward the recurrence is independent to the anatomical type and justify the need of serial echocardiographic control.
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Affiliation(s)
- A Abid
- Service de chirurgie cardiovasculaire, hôpital La Rabta, 1007 Jebbari-Bab Saadoun, Tunis, Tunisie
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Cape EG, Vanauker MD, Sigfússon G, Tacy TA, del Nido PJ. Potential role of mechanical stress in the etiology of pediatric heart disease: septal shear stress in subaortic stenosis. J Am Coll Cardiol 1997; 30:247-54. [PMID: 9207650 DOI: 10.1016/s0735-1097(97)00048-x] [Citation(s) in RCA: 95] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
OBJECTIVES The objective of this study was to show elevations in septal shear stress in response to morphologic abnormalities that have been associated with discrete subaortic stenosis (SAS) in children. Combined with the published data, this critical connection supports a four-stage etiology of SAS that is advanced in this report. BACKGROUND Subaortic stenosis constitutes up to 20% of left ventricular outflow obstruction in children and frequently requires surgical removal, and the lesions may reappear unpredictably after the operation. The etiology of SAS is unknown. This study proposes a four-stage etiology for SAS that I) combines morphologic abnormalities, II) elevation of septal shear stress, III) genetic predisposition and IV) cellular proliferation in response to shear stress. METHODS Morphologic structures of a left ventricular outflow tract were modeled based on measurements in patients with and without SAS. Septal shear stress was studied in response to changes in aortoseptal angle (AoSA) (120 degrees to 150 degrees), outflow tract convergence angle (45 degrees, 22.5 degrees and 0 degree), presence/location of a ventricular septal defect (VSD) (3-mm VSD; 2 and 6 mm from annulus) and shunt velocity (3 and 5 m/s). RESULTS Variations in AoSA produced marked elevations in septal shear stress (from 103 dynes/cm2 for 150 degrees angle to 150 dynes/cm2 for 120 degrees angle for baseline conditions). This effect was not dependent on the convergence angle in the outflow tract (150 to 132 dynes/cm2 over full range of angles including extreme case of 0 degree). A VSD enhanced this effect (150 to 220 dynes/cm2 at steep angle of 120 degrees and 3 m/s shunt velocity), consistent with the high incidence of VSDs in patients with SAS. The position of the VSD was also important, with a reduction of the distance between the VSD and the aortic annulus causing further increases in septal shear stress (220 and 266 dynes/cm2 for distances of 6 and 2 mm from the annulus, respectively). CONCLUSIONS Small changes in AoSA produce important changes in septal shear stress. The levels of stress increase are consistent with cellular flow studies showing stimulation of growth factors and cellular proliferation. Steepened AoSA may be a risk factor for the development of SAS. Evidence exists for all four stages of the proposed etiology of SAS.
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Affiliation(s)
- E G Cape
- Cardiac Dynamics Laboratory, Division of Cardiology, Children's Hospital of Pittsburgh, Pennsylvania 15213, USA
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Abstract
Congenital heart disease (CHD), cardiomyopathy, and vasculopathies are common causes of mortality and morbidity in pediatrics, including the perinatal period. This article reviews evidence that single gene defects cause many of the pediatric heart diseases. Vasculopathies discussed include Marfan's syndrome, supravalvar aortic stenosis and Williams' syndrome, Alagille's syndrome, and hereditary telangiectasia, the Osler-Weber-Rendu syndrome. Genetic causes of hypertrophic cardiomyopathy caused by sarcomeric protein mutations (beta-cardiac myosin heavy chain) and of dilated cardiomyopathy secondary to structural protein deficiencies (dystrophin) are presented. Defects in proteins essential for myocardial energy production such as oxidative phosphorylation proteins and fatty acid oxidation genes that cause cardiomyopathy or sudden death are described. Gene ablation models in mice, such as RXR alpha and homeobox gene knockouts, which result in cardiac phenotypes resembling human congenital heart disease, are described. Familial types of human CHD which are being investigated for genetic causes by positional cloning methods and known cytogenetic causes of CHD, including the CATCH-22 syndrome and monosomy at 22q11, are presented. General lessons and principles derived from these new and exciting discoveries in human cardiovascular development are surmised.
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Affiliation(s)
- A W Strauss
- Department of Pediatrics, Washington University School of Medicine, St. Louis, MO, USA
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