Influence of genes and the environment in familial congenital heart defects.

The present study aimed to investigate genetic and environmental factors involved in the pathogenesis of congenital heart disease (CHD). A total of 61 familial pedigrees with CHD were analyzed, and 134 patients out of 761 family members had a diagnosis of CHD confirmed. The present study revealed that the prevalence of CHD in first‑degree relatives (55/249, 22.0%) was significantly higher than that in second‑degree relatives (18/526, 3.4%). Additionally, the recurrence rate of CHD in families in which the patient's mother (12/61) or sister (15/61) had CHD were significantly higher than in cases with the father (6/61) or brother (4/61) having CHD. The subtypes of CHD with increased risk of recurrence were ventricle septal defect (VSD) and atrial septal defect (ASD), followed by patent ductus arteriosus and tetralogy of fallot (TOF). In the 21 sets of twins among the 61 familial pedigrees analyzed, the concordance of both twins affected by CHD in identical and dizygotic twins was 94.4% (17/18) and 33.3% (1/3), respectively. Identical subtypes of CHD were identified in 10 out of 21 sets of twins. Of note, the following pattern was identified in three sets of the twins: One twin had TOF, while the other one had VSD. A risk factor survey revealed that threatened abortion in early pregnancy was associated with familial CHD. In conclusion, genetic factors may have important roles in the development of CHD, and TOF and VSD may have similar molecular mechanisms. Threatened abortion in early pregnancy is a novel environmental factor that may be specific in Chinese females with CHD.