[Association of genetic polymorphisms in endothelial nitric oxide synthase 3 gene with recurrent early spontaneous abortion].


    To explore the association of nitric oxide synthase 3 (NOS3) gene variable number of tandem repeat(VNTR) polymorphism in intron 4 and an 894(G/T) mutation at exon 7 with recurrent early spontaneous abortion (RESA).
    One hundred and forty RESA women (patient group) and 140 healthy women with at least 1 pregnancy and without a history of pregnancy complications (control group) were included. The genotypes of NOS3 gene VNTR polymorphism were determined by polymerase chain reaction and agarose gel electrophoresis. The 894(G/T) mutation of genotypes of NOS3 gene at exon 7 was assessed by polymerase chain reaction-restrictive fragment length polymorphism.
    The frequencies of aa and ba genotypes and a allele of NOS3 gene were higher in patient group than in control group (chi square: 4.51, P< 0.05; chi square: 4.29, P<0.05). The aa and ba genotypes were significantly associated with RESA (OR:1.8, 95% CI: 1.04-3.24). There was no significant difference in TT and GT genotypes and T allele of NOS3 gene between RESA patient group and control group (chi square: 1.16, P> 0.05; chi square:1.12, P> 0.05). 894(G/T) polymorphism may be not associated with RESA.
    The genetic polymorphism of NOS3 gene 27 bp VNTR was associated with RESA. The genetic polymorphism of NOS3 gene 894(G/T) may be not associated with RESA. These results support that a allele of the NOS3 gene may be susceptibility allele.