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[Congenital cardiopathies and syndromes in adults]
1Servicio Cardiología Pediátrica, Instituto Nacional de Cardiologia Ignacio Chávez, INCICH, Juan Badiano No. 1, Col. Sección XVI, Tlalpan, 14080 México, D. F.
Insights
Congenital heart defects, often caused by genetic mutations like chromosome 22q11 microdeletions (DiGeorge syndrome) or chromosome 7 deletions (Williams-Beuren syndrome), significantly impact patient health. Early diagnosis and understanding these genetic links improve long-term outcomes.
Area of Science:
- Genetics and Molecular Biology
- Cardiology
- Developmental Biology
Context:
- Congenital heart defects (CHDs) are common birth defects with diverse causes.
- Advances in molecular biology enable understanding of genetic etiologies for CHDs.
- Improved diagnosis and treatment have increased survival and quality of life for CHD patients.
Purpose:
- To review the genetic underpinnings of specific congenital heart defects.
- To highlight the diagnostic approaches for genetic syndromes associated with CHDs.
- To discuss the clinical manifestations and genetic causes of conotruncal malformations and Williams-Beuren syndrome.
Summary:
- Conotruncal malformations result from a 22q11 microdeletion, linked to DiGeorge and cardiovelofacial syndromes, frequently causing Fallot's tetralogy and aortic arch interruption.
- Williams-Beuren syndrome, caused by a 7q11.23 deletion affecting elastin, presents with cognitive impairment, hypercalcemia, and vascular stenosis.
- Fluorescence in situ hybridization (FISH) is crucial for diagnosing the 22q11.2 microdeletion.
Impact:
- Enhanced understanding of genetic causes for CHDs.
- Improved diagnostic accuracy through genetic testing.
- Foundation for targeted therapies and genetic counseling for affected families.
Abstract:
Among congenital defects the most common are the congenital heart defects, which constitute a heterogeneous group with a multifactor etiology. A single gene mutation has been identified in some of them, such as in of Williams's syndrome, or they can be due to teratogenic agents. The advance in diagnosis and treatment of congenital heart defects has become very important because mortality has diminished and patients live longer and better, reaching adult hood. Molecular biology offers now opportunities understand the cause of many genetic diseases thanks to molecular studies of chromosomes. Conotruncal malformations are known to be caused by a microdeletion in chromosome 22(22q11), this mutation is also responsible for the DiGeorge and cardiovelofacial syndromes, the most relevant aspects are: congenital heart disease, which is present in 75% of the cases, the leading disorder is Fallot's tetralogy with pulmonary atresia, in second place is interruption of the aortic arch type B, followed by common truncus arteriosus. These patients have other phenotypic features, such as high palate, speech problems, malimplantation of ears, and protuberant nose tip, among others. Diagnosis is made with the FISH (fluorescent in situ hybridization) test that shows a microdeletion in chromosome 22 at the 11.2 region. Another syndrome that has received great attention is the Williams-Beuren syndrome, which courses with mental retardation, hypercalcemia, characteristic facies, and supravalvular aortic and pulmonary stenosis. To day, it is known that its cause is a deletion in chromosome 7(7q11.23), which affects elastin region, in consequence, affecting the vessels.