Spectrum of congenital heart defects associated with Down Syndrome in high consanguineous Omani population.

OBJECTIVE: To identify the pattern of congenital heart defects (CHD) in children with Down Syndrome (DS) in an Omani population, and compare it with CHD in children without DS and with historical cohorts from populations with low prevalence of consanguinity.
SETTING: Open-access Paediatric Echocardiography Clinic at Sultan Qaboos University Hospital, Muscat, Oman.
DESIGN: Prospective study.
METHODS: All children with DS referred to the Clinic from 1995-1998 formed the subjects (Group I). Children without DS or other known associations of CHD seen at the clinic during the same period served as controls (Group II). Two-dimensional echo-Doppler studies were performed on both groups and the results compared.
RESULTS: CHD were detected in 54/90 (60%) children in Group I, compared to 698/2122 (32.9%) in Group II (P<0.001). The common CHD in Group I included secundum atrial septal defect (ASD; 18/54), atrioventricular septal defect (AVSD; 15/54) and ventricular septal defect (VSD; 14/54), and in Group II included ASD (175/698), VSD (175/698), patent ductus arteriosus (123/698), pulmonary stenosis (PS; 76/698) and AVSD (35/698). AVSD was more common (P <0.001) and PS less common (P = 0.03) in Group I. Aortic stenosis, coarctation of aorta, transposition of great arteries and complex heart diseases were not detected. Compared to several studies from populations with low prevalence of consanguineous marriages, our study showed a higher frequency of CHD in DS (P <0.05).
CONCLUSION: A high frequency of CHD was documented in DS-children from a population with widely prevalent consanguinity. AVSD was most frequent in DS. An interesting observation was the relative rarity of some CHD in the DS population studied.