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Two family studies of children with ventricular septal defect
Insights
Genetic factors contribute significantly to isolated ventricular septal defects (VSD). This study found VSD in relatives, suggesting a heritable component and supporting a multifactorial threshold model for VSD inheritance.
Area of Science:
- Cardiology
- Genetics
- Pediatrics
Background:
- Ventricular septal defects (VSD) are common congenital heart abnormalities.
- Understanding the genetic basis of VSD is crucial for risk assessment and counseling.
Purpose of the Study:
- To investigate the familial aggregation and heritability of isolated VSD.
- To determine if VSD follows a multifactorial inheritance pattern.
Main Methods:
- Cardiological examination of first-degree relatives of VSD index patients (Sample 1).
- Questionnaire-based study of congenital abnormalities in relatives of VSD index patients (Sample 2).
- Verification of reported congenital cardiovascular malformations.
Main Results:
- VSD observed in 3.3% (Sample 1) and 1.45% (Sample 2) of siblings.
- Heritability of isolated VSD estimated at 0.57 +/- 0.22.
- Familial clustering consistent with a multifactorial threshold model.
- Other congenital cardiovascular malformations slightly elevated in relatives but within population norms.
Conclusions:
- Isolated VSD exhibits significant familial clustering, indicating a substantial genetic contribution.
- The multifactorial threshold model adequately explains the inheritance pattern of isolated VSD.
- While other congenital heart defects were slightly more prevalent in relatives, the overall pattern suggests VSD is primarily driven by specific genetic factors.
Abstract:
All first-degree relatives of 81 index patients with isolated ventricular septal defects were examined cardiologically in sample one. The congenital abnormalities in first-degree relatives of 296 index patients affected ventricular septal defects were studied by questionnaire in sample two. (The relatives reported as having congenital cardiovascular malformations were checked). Ventricular septal defects were found in 3.3% and 1.45% of sibs in samples one and two, respectively. The heritability of isolated VSD was 0.57 +/- 0.22. The familial clustering fitted the multifactorial threshold model well. Other congenital cardiovascular malformations were somewhat higher in first-degree relatives of index patients (1.6% in sample one and 1.2% in sample two) than their expected rates. The occurrence of other congenital abnormalities, however, does not exceed the prevalence at birth in the population.