Association study between variants in LHCGR DENND1A and THADA with preeclampsia risk in Han Chinese populations

Thada Is Dispensable for Female Fertility in Mice

Genome-wide association studies (GWAS) have identified THADA as one of the susceptibility genes for polycystic ovary syndrome (PCOS). Single nucleotide polymorphisms (SNPs) in the THADA gene showed significant over-transmission in PCOS and strong correlations with testosterone level. However, there was insufficient evidence to verify the effect of THADA in vivo on female reproductive system. In this study, we investigated the impacts of Thada ablation on ovarian function and reproductive outcomes with knockout (KO) mice. The results showed that the Thada deletion was insufficient to affect ovarian folliculogenesis, steroidogenesis, and female fertility. Additionally, we stressed the mice with high-fat-high-sugar diet (HFHS). In this case, the KO mice still merely had a negligible impact on ovarian function. These findings indicated that Thada deficiency was dispensable for female fertility in mice, which enriched our knowledge about in vivo functions of PCOS susceptibility genes.

A Comprehensive Overview of Common Polymorphic Variants in Genes Related to Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is one of the most common endocrine-metabolic disorders in women of reproductive age. It is characterized by an increase in the biosynthesis of androgens, anovulation, and infertility. PCOS has been reported as a polygenic entity in which multiple single nucleotide polymorphisms (SNPs) are associated with the clinical features of the pathology. Herein, we describe the common polymorphic variants in genes related to PCOS, their role in its pathogenesis, and etiology. Whole-genome association studies have been focused on women from Asian and European populations. The most common genes associated with PCOS are DENND1A, THADA, FSHR, and LHCGR. However, other genes have been associated with PCOS such as AMH, AMHR2, ADIPOQ, FTO, HNF1A, CYP19, YAP1, HMGA2, RAB5B, SUOX, INSR, and TOX3. Nevertheless, the relationship between the biological functions of these genes and the development of the pathology is unclear. Studies in each gene in different populations do not always comply with a general pattern, so researching these variants is essential for better understanding of this polygenic syndrome. Future population studies should be carried out to evaluate biological processes, incidence rates, allelic and genotypic frequencies, and genetic susceptibility factors that predispose PCOS.

Association analysis between the tag single nucleotide polymorphisms of DENND1A and the risk of polycystic ovary syndrome in Chinese Han women

Background

The DENND1A gene is one of the most important sites associated with polycystic ovary syndrome (PCOS). We attempted to analyze the correlation between five single nucleotide polymorphisms (SNPs) in the DENND1A gene and the development of PCOS.

Methods

A total of 346 PCOS patients and 225 normal ovulatory women were involved in the case-control study. Clinical variables and hormones were recorded. According to the Hap Map database, five tagging SNPs (rs2479106, rs2768819, rs2670139, rs2536951 and rs2479102) in the DENND1A gene were identified. The TaqMan probe and the PCR–RFLP (restriction fragment length polymorphism) methods were used for revealing these genotypes. TaqMan Genotype Software was used to analyze the alleles of the five SNPs.

Results

Linkage disequilibrium and the gene frequency analysis demonstrated that the CCGGG haplotype might increase the risk of PCOS (P = 0.038, OR = 1.89, 95% CI = 1.027–3.481). Significant differences were found in genotypic and allelic distributions at the rs2536951 and rs2479102 loci between PCOS women and controls (P <  0.001). The LH levels and LH/FSH ratios were higher in PCOS patients than in the control group. A detailed analysis revealed that for the rs2479106 locus, these two values were significantly different in the control subjects who had AA, AG and GG genotypes (P = 0.013 and P = 0.007, respectively), and for the rs2468819 locus, these two values were significantly different among the PCOS patients with AA, AG and GG genotypes (P = 0.013 and 0.002, respectively).

Conclusions

The tagging SNPs rs2479106 and rs2468819 in the DENND1A gene are associated with PCOS in the Chinese population, whereas rs2670139, rs2536951 and rs2479102 are not correlated with PCOS in the same population.