Oestrogen Receptor Alpha, Beta Genes and CYP17A Gene Polymorphism Analysis in Women with Uterine Leiomyoma

Abstract

Introduction: Uterine Leiomyoma is a highly morbid condition with an increasing incidence in the Asian Indian ethnicity. The pathogenesis is multifactorial and not clearly delineated, making non-surgical treatment of limited success, thus making surgical intervention prevalent. Derangement of endocrinological parameters is the most evident aspect and cause of this condition. But the root genetic cause of this hormonal imbalance has seldom been explored in Indian women suffering from uterine leiomyoma. Aim: To explore the association of Single Nucleotide Polymorphism (SNPs) rs3020449, rs4986938 and rs743572 of ER alpha, ER beta and CYP17 genes respectively in women having uterine fibroid visiting a Tertiary Care Hospital in North India. Materials and Methods: Hundred patients diagnosed with uterine leiomyoma were selected from Gynaecology Out Patient Department (OPD) of a Tertiary Care Hospital in North India and equal age matched healthy women were taken as controls randomly, with a condition that they have no close blood relative with uterine leiomyoma. The blood was collected for DNA extraction and RFLP based polymorphism detection. Bands were visualised in agarose gel for Estrogen Receptor alpha (ER alpha), ER beta and CYP17 genes. Statistical analysis was performed using Graph Pad Prism 6.0. Hardy Weinberg equilibrium was tested using Chi-square goodness of fit test. Nominal variables were analysed using Fisher-exact test. Data is presented as Mean±SEM and p-value of <0.05 was considered significant. Results: Early age at menarche (cases vs control 11.51±0.19 year vs 12.04±0.12, p=0.03) and less number of previous pregnancies (cases vs control 1.06±0.09 vs 1.41±0.12, p=0.01), which are known risk factors for the uterine fibroids, was reconfirmed in this study. The genotype distribution of all subjects studied in above genes followed Hardy Weinberg equilibrium and there was no significant difference in genotype frequencies between cases and controls [ER alpha rs9322331 C allele (cases vs controls; 62% vs 64%), T allele (38% vs 36%); ER beta rs4986938 G allele (64% vs 59%), A allele (36% vs 41%); CYP17 rs743572 T allele (44.95% vs 46.53%), C allele (55.05% vs 53.47%) p-value not significant in any]. However, there was an increased propensity of TC genotype of CYP17 rs743572 towards obesity (p<0.05). Conclusion: The allelic frequencies of all the three SNPs were similar in cases and controls indicating that they do not affect susceptibility to disease. However, the association of TC allele of CYP17 SNP with higher BMI needs further analysis.