Genetics and Immunology · Reproductive Genetics
Abstract
Context
The G protein-coupled receptor GPRC6A is an emerging effector with multiple endocrine roles, including stimulation of T production from the testis. Recently, two men with an inactivating mutation (F464Y) of GPRC6A have been identified, and they showed primary testicular failure and deranged spermatogenesis. Furthermore, one of them also reported cryptorchidism at birth. In addition, a polymorphism (rs2274911, Pro91Ser) in GPRC6A is associated with prostate cancer, a typical androgen-sensitive cancer.
Objective
To study the possible association between rs2274911 polymorphism and male fertility and/or cryptorchidism.
Design, Setting, and Patients
A total of 611 subjects, including 343 infertile patients, 197 normozoospermic controls, and 71 cryptorchid newborns, were retrospectively selected.
Methods
Sequencing analysis for rs2274911 polymorphism and F464Y mutation, and serum levels of FSH, LH, and T were assessed. In vitro functional studies for rs2274911 and F464Y were also performed.
Results
Homozygous subjects for the risk allele A of rs2274911 had a 4.60-fold increased risk of oligozoospermia and 3.52-fold increased risk of cryptorchidism. A significant trend for increased levels of LH in the GA and AA genotypes, compared with GG homozygotes, was detected in men with azoospermia/cryptozoospermia (P for trend = .027), further supporting an association with primary testicular failure. The mutation F464Y was found in one cryptorchid child (one in 71; 1.41%). Functional studies showed that the A allele of rs2274911 and the F464Y substitution were associated with lower exposition of the receptor on the cell membrane and a reduced downstream phosphorylation of ERK1/2 with respect to wild type.
Conclusion
Our results suggest that GPRC6A inactivation or sub-function contributes to reduced exposure to androgens, leading to cryptorchidism during fetal life and/or low sperm production in adulthood.
Topics
By this author
Semen Analysis · Sperm Function Testing
Preimplantation genetic testing for male factor infertility: lights and shadows
Mazzilli R et al., 2026 · Journal of endocrinological investigation
Male factor could contribute, alone or in combination with female factor, to the inability to conceive in a couple in more than half of cases. The effect of male factor infertility (MFI) on embryological assisted reproductive technology (ART) outcomes remains an ongoing discussion. to evaluate the impact of MFI on embryo aneuploidy rates, to better understand the role and possible indication for Preimplantation genetic testing for aneuploidies (PGT-A), considering the role of sperm characteristics, paternal age, sperm DNA fragmentation and sperm aneuploidies. this narrative review included all available articles, published up to January 2026. Available evidence, often based on heterogeneous and old-fashioned methodologies, suggests that MFI may impair embryonic development, particularly in terms of fertilization rate and blastulation rate, more than embryo euploidy; however, a comprehensive evaluation of MFI should be integrated into clinical practice in the context of couple infertility, to also optimize the efficiency and outcomes of ART. Promising results emerged from sperm DNA fragmentation as a tool to predict embryo euploidy, but further investigations involving larger sample sizes and improved standardization are required.
Male Factor Causes · Hormonal Causes
Pathophysiology-Based Classification of Male Infertility: Evidence from an 800-patient Prospective Cohort
Grande G et al., 2026 · The Journal of clinical endocrinology and metabolism · Free to read
Male factor infertility (MFI) is frequently labelled idiopathic when evaluation relies primarily on semen analysis, potentially overlooking endocrine and pathophysiological mechanisms relevant for targeted management. To phenotypically define MFI and develop a pathophysiology-based classification aimed at reducing idiopathic infertility following comprehensive evaluation. Prospective monocentric cohort study conducted at a tertiary referral academic centre. Eight hundred male partners of infertile couples evaluated between October 2024 and January 2026 after exclusion of isolated female factor infertility. Prevalence of MFI categories, hormonal patterns across phenotypes, and proportion of idiopathic infertility after comprehensive work-up. All patients underwent standardized clinical evaluation, hormonal assessment (total testosterone, FSH, LH), testicular ultrasound, and complete semen analysis. Microbiological testing, transrectal ultrasound, and genetic analyses were performed according to guidelines. Primary spermatogenic failure was the most prevalent category (56.0%), followed by infection/inflammation (22.4%) and hypogonadotropic hypogonadism (8.5%). Idiopathic infertility was identified in only 5.3% of cases. Distinct endocrine profiles were observed, with high-FSH spermatogenic failure representing the dominant phenotype. Comprehensive phenotyping markedly reduces the proportion of patients classified as having idiopathic infertility and identifies clinically relevant subgroups. This prospective study provides validation of a pathophysiology-based classification and supports a shift toward endocrine-integrated diagnostic strategies in male infertility, with potential implications for targeted management.
Semen Analysis · Sperm Function Testing
Beyond semen analysis: in men with normal semen parameters telomere attrition and oxidative imbalance distinguish those fertile from those with infertility
Rocca MS et al., 2026 · Journal of translational medicine · Free to read
Standard semen analysis has little prognostic value in distinguishing fertile from infertile men. Furthermore, in men with semen parameters within the reference ranges, it cannot distinguish fertile men from infertile men, i.e. partners of couples with idiopathic infertility. Oxidative stress, mitochondrial dysfunction, sperm telomere shortening, and DNA fragmentation have been proposed as contributors to impaired male fertility. However, these biomarkers have not been evaluated as a whole in subjects with normal semen parameters, partners of fertile and infertile couples. To characterise a multidimensional panel of sperm biomarkers-including sperm telomere length (STL), mitochondrial DNA copy number (mtDNAcn), reactive oxygen species (ROS), lipid peroxidation (LP), sperm chromatin dispersion (SCD), and respiratory control ratio (RCR)-and to identify whether these parameters might discriminate, in men with normal semen parameters, infertile men from fertile controls. A total of 150 men with semen parameters within the normal ranges were enrolled: 47 male partners of couples with idiopathic infertility and 103 fertile controls. STL and mtDNAcn were quantified by qPCR; ROS were assessed using OxiSperm®II with semiquantitative imaging; LP was measured spectrophotometrically in seminal plasma; SCD was used to determine DNA fragmentation; and mitochondrial function was evaluated by oxygen consumption and RCR. Correlations between biomarkers and semen parameters were analysed using Pearson or Spearman coefficients, and intergroup comparisons were adjusted for age. Semen parameters did not differ significantly between male partners of fertile and infertile couples. compared to men of fertile couples, men of infertile couples exhibited significantly shorter STL (0.57 ± 0.59 vs 1.21 ± 1.13, p_adj = 0.001) and higher oxidative stress, with both ROS (8300.9 ± 4214.8 vs 6555.3 ± 3394.3, p_adj = 0.027) and LP (88.33 ± 55.50 vs 40.29 ± 46.98, p_adj < 0.001) markedly elevated. mtDNAcn, SCD, and RCR showed no difference between the groups. Across the entire cohort, STL correlated negatively with ROS and LP and positively with RCR. ROS correlated negatively with total sperm count, motility and RCR, and positively with LP. LP displayed the strongest pattern of associations, correlating negatively with concentration, total count, motility, STL and RCR, and positively with age and volume. Among men with normal semen analysis, partners of couples with idiopathic infertility exhibit a distinct sperm molecular profile characterised by telomere shortening and oxidative imbalance. STL, ROS and LP emerged as age-independent biomarkers associated with infertility status and showed promising discriminatory ability in this cohort, supporting their integration as second-level tests to complement routine semen analysis in cases of normozoospermia.
Neoplastic Risk in Patients With Klinefelter Syndrome
Graziani A et al., 2026 · Andrology · Free to read
Besides gonadal involvement (hypogonadism, male factor infertility, and testicular hypotrophy), patients with Klinefelter syndrome (KS) may suffer from several extra-gonadic complications, including neoplastic events. The aim of this review is to summarize all major clinical evidence dealing with the association between KS and neoplastic diseases and provide practical suggestions for the management of patients with KS regarding neoplastic risk. This narrative review was conducted through a comprehensive search of the PubMed database, using combinations of the following keywords: "Klinefelter syndrome," "cancer," "neoplasm," "breast cancer," "germ cell tumor," "lymphoma," and "testosterone replacement therapy". KS is associated with a higher risk of breast cancer and mediastinal germ cell tumors and an apparent higher risk of hematological malignancies, in particular non-Hodgkin lymphoma and leukemia. Evidence on testicular cancer is limited, with no clear increase in risk attributable to KS, while prostate cancer has a lower risk and lower mortality rate. Given the complexity of the syndrome and the limited available evidence, regular clinical follow-up with targeted investigations when clinically indicated may facilitate early diagnosis and management of associated comorbidities.
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Male Endocrine and Genetic Factors · Genetic Causes of Male Infertility
Male infertility and androgen receptor gene mutations: clinical features and identification of seven novel mutations
Ferlin A et al., 2006 · Clinical endocrinology
Androgens and a functioning androgen receptor (AR) are essential for development and maintenance of the male phenotype and spermatogenesis. Consistent with this, mutations in the AR gene cause a variety of defects related to androgen insensitivity, ranging from complete feminization to phenotypic males with infertility. The aim of his study was to analyse the prevalence of AR gene mutations in male infertility and to clarify the genotype-phenotype relation. Males with infertility were recruited consecutively at the Centre for Male Gamete Cryopreservation at the University of Padova from January 1996 to January 2005. One thousand five hundred and seventeen men with < 10 million sperm/ml and 310 age-matched normozoospermic controls. Screening for AR gene mutation was done by DHPLC and sequencing, and reproductive hormone concentrations were measured. We found 20 mutations in 26 of 1517 patients (1.7%) and no mutations in controls. A high number of mutations localized in exon 1 of the AR gene coding for the transactivation domain of the protein. Of 20 mutations, 7 represent novel mutations. With respect to men without AR mutations, subjects with AR mutations have lower ejaculate volume, higher testosterone levels, higher oestradiol levels, and higher androgen sensitivity index. However, the ranges for these variables were highly overlapping between men with and without AR gene mutations. Also clinical manifestations of AR mutations are not unique and 22 men had only spermatogenic impairment. AR gene mutations are quite frequent in unselected infertile men but no specific hormonal or clinical data could be used to preselect patients at risk of mutations.
Male Endocrine and Genetic Factors · Genetic Causes of Male Infertility
The response to FSH treatment in oligozoospermic men depends on FSH receptor gene polymorphisms
Selice R et al., 2011 · International journal of andrology
In the last years, follice-stimulating hormone (FSH) receptor (FSHR) gene polymorphisms have been studied as potential risk factors for spermatogenetic failure. In this study, we have evaluated the response of FSH treatment in terms of sperm production on the basis of Ala307Thr-Asn680Ser polymorphisms in the FSHR gene in a group of oligozoospermic subjects with hypospermatogenesis and normal FSH levels. Patients were randomized into two groups: 70 treated with recombinant FSH (150 IU thrice per week for 3months) and 35 without treatment. After 3months of treatment, we observed significant increase in total sperm count, sperm concentration, forward motility, percentage of normal morphology forms and total motile sperm. When 70 treated subjects were subdivided based on FSHR genotype, only subjects with at least one serine in position 680 showed a statistically significant increase in these sperm parameters, whereas subjects with homozygote Thr307-Asn680 showed no difference in any seminal parameters evaluated. Non-treated subjects showed no differences in any parameter evaluated. This study suggests that the analysis of this gene represents a valid pharmacogenetic approach to the treatment of male infertility, confirming also the importance of strict criteria for the selection of patients to be treated with FSH.
Male Endocrine and Genetic Factors · Genetic Causes of Male Infertility
Impact of FSHB and FSHR Genes Polymorphisms on Hormonal Profile and Sperm Retrieval Outcome in Men With Klinefelter Syndrome: A Clinical-Genetic Predictive Study
Graziani A et al., 2026 · Andrology · Free to read
Genetic variability within the follicle-stimulating hormone (FSH)-related genes might contribute to phenotypic heterogeneity in patients with Klinefelter syndrome (KS), yet its clinical impact on sperm retrieval remains unclear. To investigate the association between FSHB c.211 G > T and FSHR polymorphisms (c.2039 A > G and c.29 G > A) and hormonal parameters, as well as their potential role in predicting sperm retrieval rate (SRR) in patients with KS undergoing testicular sperm extraction (TESE). A retrospective cohort of patients with KS was analyzed. Only subjects not receiving testosterone replacement therapy were included (n = 417). Hormonal, anthropometric, and clinical variables were compared across genotypes using nonparametric tests. Additive genetic models were applied to evaluate allele-dose effects. Multivariable logistic regression was performed to identify independent predictors of SRR. Predictive performance of clinical and combined clinical-genetic models was assessed using ROC curve analysis. FSHB and FSHR genes polymorphisms were associated with variations in serum FSH concentrations, confirming a modulatory role of the FSH-related genes. In additive modeling, the FSHR c.29 G > A polymorphism emerged as an independent predictor of SRR (adjusted OR: 0.29; 95% CI, 0.09-0.97), whereas FSHB c.211 G > T showed a nonsignificant trend. The inclusion of genetic variants modestly improved predictive accuracy compared with clinical variables alone, as demonstrated by ROC analysis. Genetic variants within the genes involved in FSH action might contribute incremental information for the prediction of sperm retrieval in patients with KS. While the overall predictive gain remains moderate, additive genetic modeling highlights a potential allele-dose effect of FSHR c.29 G > A on reproductive outcome, supporting a role for integrated clinical-genetic assessment in this population, although external validation remains required.
Male Endocrine and Genetic Factors · Genetic Causes of Male Infertility
Detailed functional studies on androgen receptor mild mutations demonstrate their association with male infertility
Zuccarello D et al., 2008 · Clinical endocrinology
Mutations in the androgen receptor (AR) gene can cause the androgen insensitivity syndrome (AIS). For complete and severe partial AIS, well-characterized in vitro functional assays can be used for genotype-phenotype correlation; however, for mild forms of AIS, as associated with male infertility, experimental evidence is scarce or lacking. In particular, optimal in vitro functional tests informative about the genotype-phenotype relation have not been described. The objective of this study was to investigate the association among genotype and phenotype for AR mutations found in infertile males by conventional functional assays and additional in-depth studies performed with several gene reporters. To this aim, we selected four AR missense mutations associated with isolated male infertility (L547F and two novel mutations A474V and S650G) or partial AIS (Y571H). After introduction of the specific mutations in AR expression plasmid, we performed classical in vitro studies (Western immunoblotting, electrophoretic mobility shift assay, hormone-response curves) and transactivation assays with different reporter constructs (MMTV, Sc-ARU-TK, TAT-GRE- 2X, Slp-ARU-TK and PEM). Our results showed that standard functional tests provide sufficient information only for severe AR mutations, whereas for AR mutations found in mild AIS patients with male infertility, only an extensive analysis with different in vitro systems, and in particular with PEM promoter, can give information on the functionality of the AR and therefore on the pathogenicity of the mutations and on genotype-phenotype correlation.
Genetics and Immunology › Reproductive Genetics › Single Gene Conditions · Male Fertility › Male Endocrine and Genetic Factors › Genetic Causes of Male Infertility
L De Toni, A Di Nisio, Elena Speltra, Nunzio Turiaco
E Speltra, N Turiaco
PMID 26735260 26735260 DOI 10.1210/jc.2015-3967 10.1210/jc.2015-3967 De Toni et al. 2016, De Toni 2016