Combined assessment of polymorphisms in the LHCGR and FSHR genes predict chance of pregnancy after in vitro fertilization.

STUDY QUESTION: Can gonadotrophin receptor variants separately or in combination, be used for the prediction of pregnancy chances in in vitro fertilization (IVF) trials? SUMMARY ANSWER: The luteinizing hormone/human chorionic gonadotrophin receptor (LHCGR) variant N312S and the follicle-stimulating hormone receptor (FSHR) variant N680S can be utilized for the prediction of pregnancy chances in women undergoing IVF. WHAT IS KNOWN ALREADY: The FSHR N680S polymorphism has been shown to affect the ovarian response in response to gonadotrophin treatment, while no information is currently available regarding variants of the LHCGR in this context. STUDY DESIGN, SIZE, DURATION: Cross-sectional study, duration from September 2010 to February 2015. Women undergoing IVF were consecutively enrolled and genetic variants compared between those who became pregnant and those who did not. The study was subsequently replicated in an independent sample. Granulosa cells from a subset of women were investigated regarding functionality of the genetic variants. PARTICIPANTS/MATERIALS, SETTING, METHODS: Women undergoing IVF (n = 384) were enrolled in the study and genotyped. Clinical variables were retrieved from medical records. For replication, an additional group of n = 233 women was utilized. Granulosa cells from n = 135 women were isolated by flow cytometry, stimulated with Follitropin alpha or Menotropin, and the downstream targets 3',5'-cyclic adenosine monophosphate (cAMP) and inositol 1,4,5-trisphosphate (IP3) measured with enzyme-linked immunosorbent assay. MAIN RESULTS AND THE ROLE OF CHANCE: Women homozygous for serine (S) in both polymorphisms displayed higher pregnancy rates than women homozygous asparagine (N) (OR = 14.4, 95% CI: [1.65, 126], P = 0.016). Higher pregnancy rates were also evident for women carrying LHCGR S312, regardless of FSHR variant (OR = 1.61, 95% CI: [1.13, 2.29], P = 0.008). These women required higher doses of FSH for follicle recruitment than women homozygous N (161 versus 148 IU, P = 0.030). When combining the study cohort with the replication cohort (n = 606), even stronger associations with pregnancy rates were noted for the combined genotypes (OR = 11.5, 95% CI: [1.86, 71.0], P = 0.009) and for women carrying LHCGR S312 (OR = 1.49, 95% CI: [1.14, 1.96], P = 0.004). A linear significant trend with pregnancy rate and increasing number of G alleles was also evident in the merged study population (OR = 1.34, 95% CI: [1.10, 1.64], P = 0.004). A lower cAMP response in granulosa cells was noted following Follitropin alpha stimulation for women homozygous N in both polymorphisms, compared with women with other genotypes (0.901 pmol cAMP/mg total protein versus 2.19 pmol cAMP/mg total protein, P = 0.035). LIMITATIONS, REASONS FOR CAUTION: Due to racial differences in LHCGR genotype distribution, these results may not be applicable for all populations. WIDER IMPLICATIONS OF THE FINDINGS: Despite that >250 000 cycles of gonadotrophin stimulations are performed annually worldwide prior to IVF, it has not been possible to predict neither the pregnancy outcome, nor the response to the hormone with accuracy. If LHCGR and FSHR variants are recognized as biomarkers for chance of pregnancy, more individualized and thereby more efficient treatment modalities can be developed. STUDY FUNDING, COMPETING INTERESTS: This work was supported by Interreg IV A, EU (grant 167158) and ALF governments grant (F2014/354). Merck-Serono (Darmstadt, Germany) supported the enrollment of the subjects. The authors declare no conflict of interest.

CAG repeat number is not inversely associated with androgen receptor activity in vitro.

A negative linear association between androgen receptor (AR) function and the CAG repeat numbers is generally assumed. However, in vivo data concerning the association between CAG number and androgenic effects have been conflicting. Since former in vitro studies mostly have been based on extreme CAG lengths and reporter-systems containing viral promoters, the objective of this study was to investigate ARs with CAG lengths within normal range (16, 22 and 28) in a reporter-assay with the human prostate specific antigen promoter as target. We also wished to elucidate whether the interpretation of the results was depending on the methods used for adjustment of transfection efficiency and protein content. With beta-galactosidase as transfection control, 22CAG had the highest activity (set to 100%) compared with 16CAG [mean 78% (range 41-132), P = 0.005] and 28CAG [68% (26-162), P = 0.006], whereas renilla-luciferase resulted in 16CAG behaving similar to 22CAG [104% (56-165), P = 0.7] and 28CAG having lower activity [59% (33-101), P = 0.004]. In these experiments, also the empty vector displayed considerable background activity. When adjusting for AR protein, the 22CAG genotype had the highest activity; 16CAG and 28CAG displaying 20% (10-47, P < 0.0001) and 12% (5-21, P < 0.0001) thereof. Similar results were obtained with adjustment for total protein. Thus, by normalizing for AR-content, contrary to various control vectors, the highest AR activity was confined to the 22CAG and not 16 CAG, which may at least partly explain the discrepancy in data aiming to link physiological conditions to CAG repeat length.

Modifying effect of the AR gene trinucleotide repeats and SNPs in the AHR and AHRR genes on the association between persistent organohalogen pollutant exposure and human sperm Y:X ratio.

Persistent organohalogen pollutants (POPs) have been suggested to be involved in changing the proportion of ejaculated Y-bearing sperm. The androgen receptor (AR), aryl hydrocarbon receptor (AHR) and aryl hydrocarbon receptor repressor (AHRR) may modulate the effect of POPs with regard to previously observed sperm Y:X ratio changes. The objective of this study was to investigate whether sperm Y:X ratio changes in subjects exposed to 2,2'4,4'5,5'-hexachlorobiphenyl (CB-153) and dichlorodiphenyl dichloroethene (p,p'-DDE) were modified by polymorphisms in the AR, AHR and AHRR genes. Semen for analysis of Y- and X-bearing sperm by two-colour fluorescence in situ hybridization and blood for leukocyte DNA genotyping and analysis of CB-153 and p,p'-DDE concentrations were obtained from 195 Swedish fishermen. The polymorphic CAG and GGN repeats in the AR and the R554K and P185A single-nucleotide polymorphisms in the AHR and AHRR genes, respectively, were determined by direct sequencing and allele-specific PCR. The effect of p,p'-DDE was modified by CAG or GGN repeat category in relation to the proportion of Y-bearing sperm (P = 0.005 and 0.02 for CAG and GGN, respectively). Moreover, p,p'-DDE, but not CB-153, levels were associated with Y-sperm proportion in men with CAG < 22 (P < 0.001), but not in those carrying CAG > or = 22 (P = 0.73). This association was even more pronounced in subjects carrying a short CAG repeat in combination with an AHRR G-allele. The association in regard to p,p'-DDE was found for GGN = 23 but not for the GGN < 23 or GGN > 23 subgroups (P = 0.01, 0.44 and 0.99, respectively). In conclusion The endocrine-disrupting action of POPs, in relation to the observed changes in sperm Y:X ratio, may be modulated by the genes involved in sex steroid and dioxin-mediated pathways.