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aim and Background: Recurrent spontaneous abortion is defined as the occurrence of at least three consecutive pregnancy losses prior to 20th week of gestation.Key molecules like Ran and Dicer involves in microRNA (miRNA) biogenesis,miRNAs are key regulators in many biological processes.The purpose of this study was to demonstrate whether genetic polymorphisms in miRNA machinery genes(RAN rs14035,DICER rs3742330) show an association with recurrent spontaneous abortion in woman of the city of Tehran.
Materials and Methods: one case-control study was performed with 20 healthy women (with at least one live birth and no history of pregnancy loss) and 50  patient women with  recurrent spontaneous abortion for genotyping of DICER polymorphism by tetra ARMS PCR method, another study was performed with 10 healthy women(with at least one live birth and no history of pregnancy loss)  and 40 patient women with  recurrent spontaneous abortion for genotyping of RAN polymorphism by PCR and sequencing method.Statistical data of the two polymorphism were analyzed by Chi-square and Fisher's exact test.
Results: Genotypes and alleles  of DICER(rs3742330) polymorphism showed no significant association with recurrent spontaneous abortion in the studied  group (p>0/05).Genotypes of RAN(rs14035) polymorphism showed a significant association with recurrent spontaneous abortion in the studied  group(p=0/001),but there was no significant association between this condition and RAN polymorphism in the studied group(p>0/05).
Conclusion: This study indicates that RAN(rs14035) has significant association with recurrent spontaneous abortion but this condition has no  significant association with DICER(rs3742330) .