Abstract: BACKGROUND ＆ AIM: To explore the effects of Cystathionine beta synthase (CBS) gene polymorphism in parents on occurrence of congenital heart disease (CHD) in offsprings. MATERIAL AND METHODS: 127 CHD case-parent triads were selected from Liaoning Province as case group, and 129 healthy subjects were simultaneously selected together with their biological parents as control group. For all subjects the polymorphism of CBS gene G919A locus was examined by ARMS-PCR method. RESULTS: Significant difference was found in genotype distribution and allele frequency between parents of CHD cases and of controls. Compared with wild type genotype, offsprings of mutant heterozygote and homozygote were at higher risk of CHD, with OR 0.46(95％CI: 0.31～0.69). Further comparison of each type of CHD showed that genotype frequencies in PDA patient, mothers of ASD patients,parents of VSD parents,and patients of other types of CHD were significantly different from their corresponding controls,The results of TDT analysis showed that no allele transmission disequilibrium existed in CHD nuclear families. CONCLUSION: The CBS gene G919A mutation of parents might decrease the risk of CHD in offspring.

Key words: heart defects, congenital, polymorphism (genetics), cystathionine beta synthase gene