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Familial risks of congenital heart defect assessed in a population-based epidemiologic study
Insights
This study reveals varying familial risks for congenital heart defects (CHD), suggesting complex genetic factors beyond simple multifactorial inheritance. Specific risks for isolated defects like hypoplastic left heart syndrome challenge existing models.
Area of Science:
- Cardiology
- Genetics
- Pediatrics
Background:
- Congenital heart defects (CHD) are diverse, with unknown causes in many cases.
- Previous familial risk studies for CHD may have biases.
- Understanding genetic contributions to CHD is crucial.
Purpose of the Study:
- To determine familial recurrence risks for isolated congenital heart defects.
- To analyze risks based on a pathogenic classification scheme.
- To evaluate the adequacy of the additive multifactorial model for CHD etiology.
Main Methods:
- Population-based study in the Baltimore-Washington area.
- Analysis of infant CHD cases and a control birth cohort.
- Defined recurrence rates for first-degree relatives of isolated CHD cases.
Main Results:
- Familial recurrence risks for CHD varied significantly by defect type.
- Flow lesions showed higher recurrence risks than previously reported.
- Sibling risk for hypoplastic left heart syndrome suggested autosomal recessive inheritance.
- Ventricular septal defect risks differed across mechanistic groups.
Conclusions:
- The additive multifactorial model is insufficient for all isolated CHD.
- Familial risk patterns indicate complex genetic etiologies for CHD.
- Further research is needed to elucidate specific genetic mechanisms in CHD.
Abstract:
Congenital heart defects (CHD) represent a heterogeneous group of disorders caused by chromosome abnormalities, mendelian disorders, teratogenic exposures, and unknown etiologic mechanisms. A large group of various isolated defects is presumably multifactorial in origin. Previous studies of familial risks for specific anatomic defects obtained from clinical series may include significant biases and obscured pathogenic relationships. In this population-based study we analyzed all cases of CHD in infants and a control birth cohort in the Baltimore-Washington area. The rates of CHD were defined for first-degree relatives of cases with isolated defects, grouped by a pathogenic classification scheme. Precurrence risks were found to vary among the groups, and risks for flow lesions were higher than previously reported. The sibling precurrence risk for hypoplastic left heart syndrome (13.5%) was not significantly different from that expected for an autosomal recessive mechanism; the risks for different types of ventricular septal defects (VSD) varied among mechanistic groups. The results indicate that the additive multifactorial model does not adequately account for the risks in all forms of isolated CHD of unknown etiology.