Effects of SNP of GnRH Receptor Genes in IVF Patients

Gonadotropin-releasing hormone analogue (GnRH-a) "long protocol" is a protocol for pituitary down-regulation in IVF. However, it is common in clinic that some patients are hypersensitive to pituitary down-regulation and have pituitary oversuppression, resulting in prolonged ovarian stimulation and increased consumption of exogenous gonadotropin(Gn). On the other hand, some patients may have insufficient pituitary down-regulation, which can affect the synchronization of ovarian follicles and consequently reduce the number of oocytes retrievable and lower the pregnancy rate. The differences in responses to GnRH-a among patients may be associated with the SNP of their GnRH receptor genes. It has been reported that mutations in GnRH receptor genes could change their binding affinity to the ligands, thus affecting the outcome of pituitary down-regulation. So far 20 non-synonymous mutations on the GnRH receptor genes have been reported, which can affect the function of GnRH receptor and are highly associated with disorders such as endometriosis and sexual precocity. However, the correlation between the SNP of GnRH receptor genes and the outcome of pituitary down-regulation in IVF has not been reported. The purpose of this study is to analyze the correlation between single nucleotide polymorphism (SNP) of GnRH receptor genes in infertile female patients and the extent of pituitary down-regulation by short-acting GnRH-a long protocol, with the goal to achieve individual down-regulation protocols based on the patients' SNP haplotypes of GnRH receptor genes and to improve the success rate of assisted reproductive technology.