This paper presents the 12th update of the human obesity gene map, which incorporates published results up to the end of October 2005. Evidence from single-gene mutation obesity cases, Mendelian disorders exhibiting obesity as a clinical feature, transgenic and knockout murine models relevant to obesity, quantitative trait loci (QTL) from animal cross-breeding experiments, association studies with candidate genes, and linkages from genome scans is reviewed. As of October 2005, 176 human obesity cases due to single-gene mutations in 11 different genes have been reported, 50 loci related to Mendelian syndromes relevant to human obesity have been mapped to a genomic region, and causal genes or strong candidates have been identified for most of these syndromes. There are 244 genes that, when mutated or expressed as transgenes in the mouse, result in phenotypes that affect body weight and adiposity. The number of QTLs reported from animal models currently reaches 408. The number of human obesity QTLs derived from genome scans continues to grow, and we now have 253 QTLs for obesity-related phenotypes from 61 genome-wide scans. A total of 52 genomic regions harbor QTLs supported by two or more studies. The number of studies reporting associations between DNA sequence variation in specific genes and obesity phenotypes has also increased considerably, with 426 findings of positive associations with 127 candidate genes. A promising observation is that 22 genes are each supported by at least five positive studies. The obesity gene map shows putative loci on all chromosomes except Y. The electronic version of the map with links to useful publications and relevant sites can be found at http://obesitygene.pbrc.edu.

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The human obesity gene map: the 2005 update.

The age-related decline of the success in IVF is largely attributable to a progressive decline of ovarian oocyte quality and quantity. Over the past two decades, a number of so-called ovarian reserve tests (ORTs) have been designed to determine oocyte reserve and quality and have been evaluated for their ability to predict the outcome of IVF in terms of oocyte yield and occurrence of pregnancy. Many of these tests have become part of the routine diagnostic procedure for infertility patients who undergo assisted reproductive techniques. The unifying goals are traditionally to find out how a patient will respond to stimulation and what are their chances of pregnancy. Evidence-based medicine has progressively developed as the standard approach for many diagnostic procedures and treatment options in the field of reproductive medicine. We here provide the first comprehensive systematic literature review, including an a priori protocolized information retrieval on all currently available and applied tests, namely early-follicular-phase blood values of FSH, estradiol, inhibin B and anti-Mullerian hormone (AMH), the antral follicle count (AFC), the ovarian volume (OVVOL) and the ovarian blood flow, and furthermore the Clomiphene Citrate Challenge Test (CCCT), the exogenous FSH ORT (EFORT) and the gonadotrophin agonist stimulation test (GAST), all as measures to predict ovarian response and chance of pregnancy. We provide, where possible, an integrated receiver operating characteristic (ROC) analysis and curve of all individual evaluated published papers of each test, as well as a formal judgement upon the clinical value. Our analysis shows that the ORTs known to date have only modest-to-poor predictive properties and are therefore far from suitable for relevant clinical use. Accuracy of testing for the occurrence of poor ovarian response to hyperstimulation appears to be modest. Whether the a priori identification of actual poor responders in the first IVF cycle has any prognostic value for their chances of conception in the course of a series of IVF cycles remains to be established. The accuracy of predicting the occurrence of pregnancy is very limited. If a high threshold is used, to prevent couples from wrongly being refused IVF, a very small minority of IVF-indicated cases (~3%) are identified as having unfavourable prospects in an IVF treatment cycle. Although mostly inexpensive and not very demanding, the use of any ORT for outcome prediction cannot be supported. As poor ovarian response will provide some information on OR status, especially if the stimulation is maximal, entering the first cycle of IVF without any prior testing seems to be the preferable strategy.

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A systematic review of tests predicting ovarian reserve and IVF outcome

Aging in men is accompanied by a progressive, but individually variable decline of serum testosterone production, more than 20% of healthy men over 60 yr of age presenting with serum levels below the range for young men. Albeit the clinical picture of aging in men is reminiscent of that of hypogonadism in young men and decreased testosterone production appears to play a role in part of these clinical changes in at least some elderly men, the clinical relevancy of the age-related decline in sex steroid levels in men has not been unequivocally established. In fact, minimal androgen requirements for elderly men remain poorly defined and are likely to vary between individuals. Consequently, borderline androgen deficiency cannot be reliably diagnosed in the elderly, and strict differentiation between “substitutive” and “pharmacological” androgen administration is not possible. To date, only a few hundred elderly men have received androgen therapy in the setting of a randomized, controlled study, and many of th...

https://www.hormonebalance.org/images/documents/Kauffman%2005%20TDS%20REVIEW%20ER.pdf

The decline of androgen levels in elderly men and its clinical and therapeutic implications.

Endometrial cancer is a disease of the affluent, developed world, where epidemiological studies have shown that > or =40% of its incidence can be attributed to excess body weight. An additional proportion may be because of lack of physical activity. Alterations in endogenous hormone metabolism may provide the main links between endometrial cancer risk, and excess body weight and physical inactivity. Epidemiological studies have shown increased endometrial cancer risks among pre- and postmenopausal women who have elevated plasma androstenedione and testosterone, and among postmenopausal women who have increased levels of estrone and estradiol. Furthermore, there is evidence that chronic hyperinsulinemia is a risk factor. These relationships can all be interpreted in the light of the "unopposed estrogen" hypothesis, which proposes that endometrial cancer may develop as a result of the mitogenic effects of estrogens, when these are insufficiently counterbalanced by progesterone. In our overall synthesis, we conclude that development of ovarian hyperandrogenism may be a central mechanism relating nutritional lifestyle factors to endometrial cancer risk. In premenopausal women, ovarian hyperandrogenism likely increases risk by inducing chronic anovulation and progesterone deficiency. After the menopause, when progesterone synthesis has ceased altogether, excess weight may continue increasing risk through elevated plasma levels of androgen precursors, increasing estrogen levels through the aromatization of the androgens in adipose tissue. The ovarian androgen excess may be because of an interaction between obesity-related, chronic hyperinsulinemia with genetic factors predisposing to the development of ovarian hyperandrogenism.

https://cebp.aacrjournals.org/content/cebp/11/12/1531.full.pdf

Obesity, endogenous hormones, and endometrial cancer risk: a synthetic review.

This paper presents the eleventh update of the human obesity gene map, which incorporates published results up to the end of October 2004. Evidence from single-gene mutation obesity cases, Mendelian disorders exhibiting obesity as a clinical feature, transgenic and knockout murine models relevant to obesity, quantitative trait loci (QTLs) from animal cross-breeding experiments, association studies with candidate genes, and linkages from genome scans is reviewed. As of October 2004, 173 human obesity cases due to single-gene mutations in 10 different genes have been reported, and 49 loci related to Mendelian syndromes relevant to human obesity have been mapped to a genomic region, and causal genes or strong candidates have been identified for most of these syndromes. There are 166 genes which, when mutated or expressed as transgenes in the mouse, result in phenotypes that affect body weight and adiposity. The number of QTLs reported from animal models currently reaches 221. The number of human obesity QTLs derived from genome scans continues to grow, and we have now 204 QTLs for obesity-related phenotypes from 50 genome-wide scans. A total of 38 genomic regions harbor QTLs replicated among two to four studies. The number of studies reporting associations between DNA sequence variation in specific genes and obesity phenotypes has also increased considerably with 358 findings of positive associations with 113 candidate genes. Among them, 18 genes are supported by at least five positive studies. The obesity gene map shows putative loci on all chromosomes except Y. Overall, >600 genes, markers, and chromosomal regions have been associated or linked with human obesity phenotypes. The electronic version of the map with links to useful publications and genomic and other relevant sites can be found at http://obesitygene.pbrc.edu.

https://onlinelibrary.wiley.com/doi/pdf/10.1038/oby.2005.50

The human obesity gene map: the 2004 update.

As both gonadotropins, LH and FSH, are required for normal spermatogenesis, patients with pituitary insufficiency need hCG plus human menopausal gonadotropin therapy to induce spermatogenesis and establish fertility. In a patient hypophysectomized because of a pituitary tumor, who, despite undetectable serum gonadotropin levels, had normal testis volume and semen parameters and fathered three children under testosterone substitution alone, we hypothesized an activating mutation of the FSH receptor. Exon 10 of the FSH receptor gene was amplified from genomic DNA by PCR, screened by single stranded conformation polymorphism gel electrophoresis, and sequenced. We identified a heterozygous A-->G base change at nucleotide position 1700, leading to an Asp-->Gly transition in codon 567 in the third intracytoplasmatic loop. COS-7 cells transiently transfected with the mutated receptor displayed a 1.5-fold increase in basal cAMP production compared to wild-type receptor, indicating that this mutation leads to liga...

/pdf/an-activating-mutation-of-the-follicle-stimulating-hormone-1jb1mxxp97.pdf

An activating mutation of the follicle-stimulating hormone receptor autonomously sustains spermatogenesis in a hypophysectomized man.

Several reports have documented the derivation of pluripotent cells (multipotent germline stem cells) from spermatogonial stem cells obtained from the adult mouse testis. These spermatogonia-derived stem cells express embryonic stem cell markers and differentiate to the three primary germ layers, as well as the germline. Data indicate that derivation may involve reprogramming of endogenous spermatogonia in culture. Here, we report the derivation of human multipotent germline stem cells (hMGSCs) from a testis biopsy. The cells express distinct markers of pluripotency, form embryoid bodies that contain derivatives of all three germ layers, maintain a normal XY karyotype, are hypomethylated at the H19 locus, and express high levels of telomerase. Teratoma assays indicate the presence of human cells 8 weeks post-transplantation but limited teratoma formation. Thus, these data suggest the potential to derive pluripotent cells from human testis biopsies but indicate a need for novel strategies to optimize hMGSC culture conditions and reprogramming.

https://stemcellsjournals.onlinelibrary.wiley.com/doi/pdf/10.1634/stemcells.2008-0439

Isolation and Characterization of Pluripotent Human Spermatogonial Stem Cell-Derived Cells

Aberrant imprinting in spermatozoa in a subset of infertile men has been postulated to be a risk factor for congenital diseases in children conceived via assisted reproduction techniques (ART). Studies in clinically well characterized large cohorts, however, have been missing. Using bisulfite sequencing, we determined the degree of methylation of the IGF2/H19 imprinting control region 1 (ICR1) and MEST differentially methylated regions in swim-up purified spermatozoa from 148 idiopathic infertile men and 33 normozoospermic controls. All control individuals had a high degree of IGF2/H19 ICR1 and a low degree of MEST methylation. Low sperm counts were clearly associated with IGF2/H19 ICR1 hypomethylation and, even stronger, with MEST hypermethylation. MEST hypermethylation, but not IGF2/H19 ICR1 hypomethylation was found in idiopathic infertile men with progressive sperm motility below 40% and bad sperm morphology below 5% normal spermatozoa. Ageing could be ruled out as a cause for the observed methylation defects. Sequence analysis of the CTCFL gene in peripheral blood DNA from 20 men with severe methylation defects revealed several polymorphisms, but no bona fide mutation. We conclude that idiopathic male infertility is strongly associated with imprinting defects at IGF2/H19 ICR1 and MEST, with aberrant MEST methylation being a strong indicator for sperm quality. The male germ cell thus represents a potential source for aberrant epigenetic features in children conceived via ART.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-2605.2009.01000.x

Idiopathic male infertility is strongly associated with aberrant methylation of MEST and IGF2/H19 ICR1.

The FSH receptor shows three single nucleotide polymorphisms (SNPs), one in the promoter and two in exon 10. In addition, the FSH receptor mRNA undergoes extensive alternative splicing. While no physiological role for the SNP in the promoter and for alternative spliced isoforms has been demonstrated so far, the SNPs in exon 10 result in four discrete allelic variants characterized by the amino acid combinations Thr307-Asn680, Ala307-Ser680, Ala307-Asn680 and Thr307-Ser680. Several studies have demonstrated that the first two allelic variants are very frequent (approximately 60 and 40% respectively) in the Caucasian population. The rarer Ala307-Asn680 and Thr307-Ser680 variants are much less frequent (<5%) in the Chinese. In males the FSH receptor variants are not related to testicular volume, serum FSH or serum inhibin B levels. The two most common receptor variants transiently transfected in COS-7 cells displayed similar functional characteristics. Frequency distribution of the two polymorphisms in normal women and patients with polycystic ovarian syndrome or premature ovarian failure is still under investigation. The homozygous Ala307-Ser680 variant seems to be associated with significantly higher basal serum FSH levels and with a higher amount of FSH required for ovarian stimulation in women undergoing assisted reproduction. This suggests that the FSH receptor genotype can influence the ovarian response to FSH stimulation. The presence of SNPs in the FSH receptor gene capable of modifying FSH action paves the way for future patient-tailored, genotype-based hormone therapies.

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Isoforms and single nucleotide polymorphisms of the FSH receptor gene: implications for human reproduction

Aims/hypothesis. The relationship of androgens to the metabolic syndrome has not been resolved. The polymorphic number of CAG repeats within the androgen receptor gene is inversely associated with the transcriptional activity of target genes.This polymorphism might thus influence testosterone effects on body fat content and serum concentrations of leptin and insulin. The direct and indirect role of androgens within the metabolic syndrome should become clearer if this genetically determined effector is taken into account. Methods. The hypothesis was investigated in a crosssectional study involving 106 healthy 20–50 year old males. Results. Multiple regression models showed a positive independent correlation of the CAG repeat number with body fat content, leptin and insulin (partial r=0.39, 0.36 and 0.28, p<0.001, p<0.001 and p=0.006, respectively). Factor analysis yielded a five-dimensional model: two dimensions were influenced by the androgen receptor polymorphism, namely “body composition” which consisted of leptin, body fat mass, insulin, the number of CAG repeats (positive loadings) and physical activity (negative loading), and “lipid profile” which comprised low density lipoprotein cholesterol, cigarette smoking, triglycerides (positive loadings) as well as high density lipoprotein cholesterol and number of CAG repeats (negative loadings). Conclusions/interpretation. A low number of CAG repeats were independently associated with protective parameters (low body fat mass and plasma insulin) as well as with adverse parameters (low high density lipoprotein cholesterol concentrations). This suggests that the pivotal role of this polymorphism in modulating androgen effects on cardiovascular risk factors is of a complex nature and implies that its clinical impact, similar to that of androgens, is dependent on exogenous cofactors. [Diabetologia (2003) 46:31–39]

/pdf/the-cag-repeat-polymorphism-in-the-androgen-receptor-gene-2xj2qi69ya.pdf

Joerg Gromoll

Papers

An activating mutation of the follicle-stimulating hormone receptor autonomously sustains spermatogenesis in a hypophysectomized man.

Isolation and Characterization of Pluripotent Human Spermatogonial Stem Cell-Derived Cells

Idiopathic male infertility is strongly associated with aberrant methylation of MEST and IGF2/H19 ICR1.

Isoforms and single nucleotide polymorphisms of the FSH receptor gene: implications for human reproduction

The CAG repeat polymorphism in the androgen receptor gene modulates body fat mass and serum concentrations of leptin and insulin in men