Parental consanguinity and congenital heart malformations in a developing country

The association between isolated congenital heart defects and consanguinity was examined in 759 Lebanese patients with different types of congenital heart malformations. The subjects were patients of the Children's Cardiac Registry Center (CCRC) at the American University of Beirut Medical Center. The proportion of first-cousin marriages among cardiac subjects was compared to that of the National Collaborative Perinatal Neonatal Network (NCPNN), after adjusting for the subjects' geographic distribution, and to the highest proportion reported by NCPNN. In general, the proportion of overall parental consanguinity and first-cousin matings among CCRC subjects (34.7 and 20.2%, respectively) were significantly higher than the highest proportion of first-cousin marriages reported by NCPNN (Bekaa subjects; 13.2%) (P < 0.0001). Comparison with the NCPNN-adjusted first-cousin mating proportion revealed a significantly increased rate of consanguinity in all categories of cardiac malformations except great vessel and coronary artery lesions (P < 0.05). The following lesions were significantly associated with increased parental consanguinity: aortic anomalies (aortic insufficiency, aortic stenosis, bicuspid aortic valve), atrial septal defect, double-outlet right ventricle, pulmonary atresia, patent ductus arteriosus, pulmonic stenosis, tetralogy of Fallot, and ventricular septal defect (P < 0.05). Higher maternal education was the only variable that was negatively correlated with parental consanguinity (P = 0.037). Our study emphasizes the role of homozygous recessive genes in the causation of different types of isolated congenital heart malformations, known to follow a multifactorial pattern of inheritance. There is an urgent need for educating the public on the deleterious effects of inbreeding, especially in developing countries with high overall consanguinity rates and limited financial resources.