Down's syndrome and the pattern of congenital heart disease in a community with high parental consanguinity.

Background: It is speculated that parents' consanguinity status effects the pattern of congenital heart defects (CHDs). In this study the CHD pattern in children with Down's syndrome (DS) was determined in a Saudi population with a high consanguineous marriage rate and compared with historical cohorts from populations with low prevalence of parental consanguinity.

Material/methods: The prospective study was conducted in an open-access pediatric echocardiography clinic in Riyadh, Saudi Arabia. The subjects were all children with DS proven by clinical and cytogenetic study and referred to the pediatric cardiology service from 2001-2004. Parents' consanguinity was documented and 2D echocardiography and Doppler studies were performed after physical examination, ECG, and chest X-ray for each patient.

Results: CHDs were detected in 54/110 (49%) children. These included ventricular septal defect (VSD: 23/54), patent ductus arteriosus (PDA: 4/54), secundum atrial septal defect (ASD: 14/54), atrioventricular septal defect (AVSD: 8/54), tetralogy of Fallot (2/54), bicuspid aortic valve (1/54), supra-pulmonary stenosis (1/54), and double outlet right ventricle (1/54). Consanguinity was found in 25% of all parents. Aortic stenosis, coarctation of the aorta, transposition of great arteries, and complex heart diseases were not detected.

Conclusions: A slightly higher frequency of CHD was documented in DS children from this population with a high consanguineous marriage rate. The frequencies of specific lesions were similar to those reported locally and internationally; VSD was the most frequently detected in this study. Interesting was the predominance of left-right shunt lesions and the relative rarity of cyanotic and complex CHD in this DS population.