RESUMEN
To investigate the relationships between unexplained recurrent spontaneous abortion [RSA] and single nucleotide polymorphisms tumor necrosis factor-alpha [TNF-alpha] [-238 G/A, -308 G/A], interleukin [IL]-6 [-634 G/C] and IL-10 [-592 C/A] in the promoter region of 3 different interleukin [TNF- alpha, IL-6, and IL-10] genes. The study group comprised 65 women [mean age: 34.1 +/- 6. 2; range: 15-45 years] with unexplained RSA, consecutively referred to the Recurrent Abortion Clinic, King Khaled University Hospital, Riyadh, Kingdom of Saudi Arabia from January 2010 to January 2011. The control group consisted of 65 females with at least 2 successful pregnancies and no history of abortion. Blood samples were drawn and deoxyribonucleic acid [DNA] was extracted using Puregene DNA purification kit. Utilizing polymerase chain reaction, the promoter region was amplified and sequenced on an Applied Biosystems Integrated sequencer to study the polymorphic sites of interest. All polymorphisms were identified in the case and control samples. A significant association was identified only between the -308 G/A polymorphism in the TNF- alpha gene promoter and the occurrence of unexplained RSA, and there was no significant association with other positions. The TNF- alpha gene polymorphism at position -308 could be a genetic predisposing factor for unexplained RSA