Abstract
Congenital heart disease (CHD) is responsible for one-third of all congenital anomalies in newborns and is the most frequent cause of infant deaths. Several cohort studies show that down syndrome (DS) and CHD are associated, and maternal hyperhomocysteinemia is an independent risk factor for CHD. In Saudi Arabia CHD represents one of the most important health problems. Here we examined the association between methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms and CHD and DS co-inheritance in patients from Al Madinah, Saudi Arabia. MTHFR rs1801133 and rs1801131 polymorphisms were genotyped in 99 CHD patients with or without DS and 126 ethnically matched controls by allelic discrimination. Of 99 patients with CHD, 26 had DS. MTHFR rs1801133 and rs1801131genotypes and alleles were not significantly different between controls and CHD patients. Further, in CHD individuals, these genotypes failed to show any significant association with DS. However, maternal age increased the risk of CHD in DS (OR=5.32; 95% CIs 1.43-19.82; p=0.013). Mantel-Haenszel analysis showed that MTHFR polymorphisms confounded the effect of maternal age CHD in DS. MTHFR polymorphisms appear to be risk factors for CHD in DS.