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Population-based study of congenital heart defects in Down syndrome
S B Freeman1, L F Taft, K J Dooley
1Department of Genetics, Emory University, Atlanta, Georgia 30322, USA. sfreeman@genetics.emory.edu
Insights
Congenital heart defects (CHDs) affect nearly half of infants with Down syndrome (DS), also known as trisomy 21. This population-based study identified specific CHDs in DS infants, aiding in understanding their prevalence.
Area of Science:
- Genetics and Developmental Biology
- Pediatric Cardiology
- Public Health Epidemiology
Background:
- Down syndrome (DS), or trisomy 21, is characterized by intellectual disability and hypotonia, with congenital heart defects (CHDs) occurring in a significant subset of individuals.
- Previous studies on CHD frequency in DS lacked comprehensive ascertainment within defined geographic populations.
- The Atlanta Down Syndrome Project offers a unique population-based resource for studying trisomy 21 and associated conditions.
Purpose of the Study:
- To determine the prevalence and types of congenital heart defects (CHDs) in infants with Down syndrome (DS) within a defined geographic area.
- To provide accurate epidemiological data on CHD in trisomy 21 through a population-based study.
- To highlight the importance of early cardiac evaluation in infants diagnosed with Down syndrome.
Main Methods:
- Population-based ascertainment of all trisomy 21 livebirths in a five-county Atlanta area over 6.5 years.
- Collection of cardiac diagnoses for 93% of identified infants, with 89% confirmed by echocardiography, cardiac catheterization, surgery, or autopsy.
- Detailed analysis of CHD types, including atrioventricular septal defects, ventricular septal defects, and others.
Main Results:
- A birth prevalence of 9.6/10,000 for trisomy 21 was observed.
- Congenital heart defects (CHDs) were diagnosed in 44% of the 227 infants with Down syndrome (DS).
- Atrioventricular septal defects were the most common CHD (45%), followed by ventricular septal defects (35%).
Conclusions:
- Congenital heart defects (CHDs) are highly prevalent in infants with Down syndrome (DS), affecting nearly half of those studied.
- This population-based study provides robust data on CHD types and frequencies in trisomy 21.
- Accurate diagnosis and characterization of CHDs in DS are crucial for appropriate clinical management and research.
Abstract:
Mental retardation and hypotonia are found in virtually all Down syndrome (DS) individuals, whereas congenital heart defects (CHDs) are only present in a subset of cases. Although there have been numerous reports of the frequency of CHDs in DS, few of the studies have had complete ascertainment of DS in a defined geographic area. The Atlanta Down Syndrome Project, a population-based study of infants born with trisomy 21, provides such a resource. In the first 6.5 years of the study, 243 trisomy 21 livebirths were identified in the five-county Atlanta area (birth prevalence: 9.6/10,000). Cardiac diagnoses were available on 227 (93%) of the cases and 89% of these evaluations were made by echocardiography, cardiac catheterization, surgery, or autopsy. Of the 227 DS infants, 44% had CHDs including 45% atrioventricular septal defect (with or without other CHDs), 35% ventricular septal defect (with or without other CHDs), 8% isolated secundum atrial septal defect, 7%, isolated persistent patent ductus arteriosus, 4% isolated tetralogy of Fallot, and 1% other. This report is unique in that it contains the largest number of trisomy 21 infants ascertained in a population-based study where modern techniques for diagnosing cardiac abnormalities predominate.