BackgroundThe breakpoints and mechanisms of ring chromosome formation were studied and mapped in 14 patients.MethodsSeveral techniques were performed such as genome-wide array, MLPA (Multiplex Ligation-Dependent Probe Amplification) and FISH (Fluorescent in situ Hybridization).ResultsThe ring chromosomes of patients I to XIV were determined to be, respectively: r(3)(p26.1q29), r(4)(p16.3q35.2), r(10)(p15.3q26.2), r(10)(p15.3q26.13), r(13)(p13q31.1), r(13)(p13q34), r(14)(p13q32.33), r(15)(p13q26.2), r(18)(p11.32q22.2), r(18)(p11.32q21.33), r(18)(p11.21q23), r(22)(p13q13.33), r(22)(p13q13.2), and r(22)(p13q13.2). These rings were found to have been formed by different mechanisms, such as: breaks in both chromosome arms followed by end-to-end reunion (patients IV, VIII, IX, XI, XIII and XIV); a break in one chromosome arm followed by fusion with the subtelomeric region of the other (patients I and II); a break in one chromosome arm followed by fusion with the opposite telomeric region (patients III and X); fusion of two subtelomeric regions (patient VII); and telomere-telomere fusion (patient XII). Thus, the r(14) and one r(22) can be considered complete rings, since there was no loss of relevant genetic material. Two patients (V and VI) with r(13) showed duplication along with terminal deletion of 13q, one of them proved to be inverted, a mechanism known as inv-dup-del. Ring instability was detected by ring loss and secondary aberrations in all but three patients, who presented stable ring chromosomes (II, XIII and XIV).ConclusionsWe concluded that the clinical phenotype of patients with ring chromosomes may be related with different factors, including gene haploinsufficiency, gene duplications and ring instability. Epigenetic factors due to the circular architecture of ring chromosomes must also be considered, since even complete ring chromosomes can result in phenotypic alterations, as observed in our patients with complete r(14) and r(22).

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Kisspeptin is involved in the control of human reproduction bridging the gap between the sex steroid levels and feedback mechanisms that control the gonadotropin releasing hormone (GnRH) secretion; however, studies considering this peptide and infertility are limited. We conducted a review and critical assessment of available evidence considering kisspeptin structure, physiology, function in puberty and reproduction, its role in assisted reproduction treatments, kisspeptin dosage and the impact on KISS1 and GPR54 genes. Literature searches were conducted in PubMed using keywords related to: (i) kisspeptin or receptors, kisspeptin-1 (ii) reproduction or infertility or fertility (iii) gene and (iv) dosage or measurement or quantification or serum level, in human. Kisspeptin is a product of KISS1 gene that binds to a G-protein-coupled receptor (GPR54/KISS1R) stimulating the release of GnRH by hypothalamic neurons, leading to secretion of pituitary gonadotropins (LH and FSH) and sexual steroids, which in turn will act in the gonads to produce the gametes. Kisspeptin is being recognized as a crucial regulator of the onset of puberty, the regulation of sex hormone mediated secretion of gonadotropins, and the control of fertility. Inactivating and activating mutations in both KISS1 or GPR54 genes were associated with hypogonadotropic hypogonadism and precocious puberty. Despite this, studies considering kisspeptin and infertility are scarce. The understanding of the role of kisspeptin may lead to its use as a biomarker in infertility treatments and use in controlled ovarian hyperstimulation.

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The data suggest that MTHFR C677T and A1298C could be important genetic factors predisposing to infertility in Brazilian infertile men.

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Background: In human assisted reproduction, the ovarian response to exogenous recombinant Follicle-stimulating Hormone (FSH) therapy is variable and difficult to predict. The standard protocol of ovarian hyperstimulation can result in satisfactory response; however, an unsatisfactory response necessitates FSH dose adjustment or results in ovarian hyperstimulation syndrome (OHSS). Polymorphisms in AMH and AMHR2 genes appear to affect hormone biological activities, thus affecting follicle recruitment and development, leading to infertility. We aimed to evaluate AMH and AMHR2 polymorphisms in infertile women, and correlate those findings with AMH, FSH and estradiol serum level response to controlled ovarian hyperstimulation (COH), as well as assisted reproduction outcomes. Methods: A cross-sectional study comprising 186 infertile women that underwent one cycle of high complexity assisted reproductive treatment. Blood samples were collected and a TaqMan assay was used for AMH G146T/rs10407022 and AMHR2 A-482G/rs2002555, A10G/rs11170555, C1749G/rs2071558 and G4952A/rs3741664 genotyping, and FSH, estradiol and AMH levels were measured. The findings were correlated to human reproduction outcomes. Results: AMH rs10407022 and AMHR2 rs2002555 polymorphisms were not associated with hormonal measurements, whereas AMHR2 rs11170555 and rs3741664 were positively associated with AMH, estradiol and FSH levels. The genotype distribution of AMH and AMHR2 genes according to Controlled Ovarian Hyperstimulation did not show a positive association. However, an association with AFC, degree of oocyte maturation (allele G of AMHR2 rs2071558) the number of embryos produced (alleles T and G of AMH rs10407022 and AMHR2 rs2002555, respectively) and frozen embryo (allele G of AMHR2 rs11170555) were found to be statistically associated. Considering COH, serum AMH and AFC were a positive predictor to OHSS. Regarding serum AMH and assisted reproduction outcomes, a positive correlation with all variables studied was found. Comparing AFC and AMH as predictors of human reproduction outcomes, the AFC was less effective than serum AMH. Considering pregnancy rates, no marker was positively associated. Conclusion: AMHR2 polymorphisms were associated with estradiol, AMH and FSH measurements, as well as number and quality of embryos, while AMH polymorphisms was associated with number of embryos produced. Serum AMH was correlated with nearly all variables analyzed in assisted reproductive treatment, demonstrating that it represents a better biomarker of OHSS and human reproduction outcomes compared to AMH and AMHR2 polymorphisms.