The rs6296 polymorphism in the 5-HT1b receptor in Dutch men with lifelong premature ejaculation: a genetic case-control association study.

BACKGROUND: Lifelong premature ejaculation (LPE) is a rare sexual condition believed to be caused by genetic neurobiological disorders. AIM: In this study we sought to evaluate the genetic association between the rs6296 polymorphism of the 5-HT1b receptor and intravaginal ejaculation latency times (IELTs) in men with LPE compared with men in a control group. METHODS: This study was a prospective observational genetic case-control association study. The LPE definition of the International Society for Sexual Medicine (ISSM) 2013 was used. Patients were recruited in 2005-2009 while attending the department of Neurosexology, HagaZiekenhuis, the Netherlands. We obtained IELTs with the stopwatch method. Polymerase chain reaction (PCR) was used for genotyping rs6296. A randomly selected group of European Caucasian men from the 1000GENOMES project was used as a control group. OUTCOMES: Study outcomes included results of comparisons of analysis of variance (ANOVA) tests between genotypes and IELTs in study participants, genotypes of cases and controls determined with the chi-square test, and expressions of allelotype- and genotype-specific risks for LPE determined with odds ratios. RESULTS: In total, 67 men with LPE were included in this study. The geometric mean (SD) IELT was 32.0 (27.4) seconds and was non-normally distributed. Genotype frequencies consisted of 29 (43.3%) GG, 31 (46.3%) GC, and 7(10.4%) CC individuals in the LPE group. Log-transformed IELTs were not statistically significant (per ANOVA tests) in men with GG, GC, or CC genotypes (P = .54). Genotype frequencies consisted of 16 (6.6%) GG; 93 (38.8%) GC, and 131 (54.6%) CC individuals in the control group (n = 240). Significant differences were found when comparing allele (P = 1.02e-17) and genotype (P = 3.22e-16) frequencies in cases and controls using a chi-square test. A statistically significant increased risk for LPE was found for carriers of the G allele (OR 5.62; 95% CI 4.13-9.42). Statistically significant risks were also found for the CG genotype (OR 6.24; 95% CI 2.63-14.77) and the GG genotype (OR 33.92; 95% CI 12.79-89.93). CLINICAL IMPLICATIONS: By investigating polymorphisms in target genes the neuro-pathophysiology of LPE could be further elaborated, potentially leading to more effective treatment. STRENGTHS AND LIMITATIONS: This is to our knowledge the first study investigating rs6296 with regard to LPE. By using a strict definition for LPE (ISSM 2013) and using the stopwatch method for measuring IELTs, bias in selection of true LPE patients will be relatively low. This study is limited by a relatively small study population and the lack of IELT data in the control group. CONCLUSIONS: This study shows a genetic association in rs6296 in men with LPE compared with healthy controls. This result warrants attempted replication in future studies.

Influence of TPH2 and HTR1A polymorphisms on lifelong premature ejaculation risk among the chinese Han population.

BACKGROUND: Lifelong premature ejaculation (LPE) is one of the most common ejaculatory dysfunctions in men. The serotonin (5-HT) synthesis rate-limiting enzyme (TPH2) and receptor (HTR1A) in the 5-HT regulatory system may play a key role in the pathogenesis of LPE. However, there are few studies on the effects of TPH2 and HTR1A polymorphisms on LPE risk. We speculated that TPH2 and HTR1A polymorphisms may affect the occurrence and development of LPE in the Chinese Han population. METHODS: In this study, 91 patients with LPE and 362 normal controls aged 18 to 64 years were enrolled in the male urology department of Hainan General Hospital in China from January 2016 to December 2018. The SNPs in HTR1A and TPH2, which are related to 5-HT regulation, were selected as indexes to genotype the collected blood samples of participants. Logistic regression was used to analyze the correlation between SNPs of HTR1A and TPH2 with LPE susceptibility, as well as the relationship with leptin, 5-HT and folic acid levels. RESULTS: The results revealed that HTR1A-rs6295 increased LPE risk in recessive model. Rs11178996 in TPH2 significantly reduced susceptibility to LPE in allelic (odds ratio (OR) = 0.68, 95% confidence interval (95% CI) = 0.49-0.96, p = 0.027), codominant (OR = 0.58, 95% CI = 0.35-0.98, p = 0.040), dominant (OR = 0.58, 95% CI = 0.36-0.92, p = 0.020), and additive (OR = 0.71, 95% CI = 0.52-0.98, p = 0.039) models. Grs11179041Trs10879352 could reduce the risk of LPE (OR = 0.44, 95% CI = 0.22-0.90, p = 0.024) by haplotype analysis. CONCLUSION: HTR1A-rs6295 and TPH2-rs11178996 are associated with LPE risk in the Chinese Han population based on the finding of this study.

His452Tyr 5-HT2A polymorphism and intravaginal ejaculation latency time in Dutch men with lifelong premature ejaculation.

Lifelong premature ejaculation (LPE) may have heritable components. Selective serotonin reuptake inhibitors have been proven effective in prolonging intravaginal ejaculation latency time (IELT). Given that serotonergic pathways are involved in the ejaculation mechanism, we aimed to investigate whether His452Tyr, also known as the C1354T (RS6314) polymorphism of the 5-HT2A receptor, contributes to LPE pathogenesis and IELT differences among patients with LPE. Dutch Caucasian men with LPE (n = 65) attending the Outpatient Department of Neurosexology, HagaZiekenhuis for drug treatment for LPE in 2009 were selected and included in this case-control study. IELT during coitus was measured using a stopwatch, and all men were genotyped for the His452Tyr polymorphism. Analysis of variance (ANOVA) was performed to determine the association between the genotypes and IELTs. Mean IELTs with standard deviations were 29.7 (±20.9), 31.5 (±14.7), and 26.0 s, and the frequencies were 83.1%, 15.4%, and 1.5% for the CC, CT, and TT groups, respectively, with an average IELT of 29.9 s. No difference in mean IELT was observed between these groups. In the affected group, the frequencies of alleles C and T were 90.8% and 9.2%, respectively; whereas those among randomly selected European Caucasian male controls (n = 503) from the CEPH database were of 92.0% and 8.0%, respectively. No significant difference was observed between the groups. Therefore, no correlation was found between the His452Tyr polymorphism and IELT distribution in patients with LPE.

Effects of CYP24A1 polymorphisms on premature ejaculation: a case-control study.

Premature ejaculation (PE) is a common male sexual dysfunction disorder, and is considered to have the genetic predisposition. However, the internal regulation mechanisms is still unclear. Hence, this study intended to explore the effects of genetic polymorphisms of CYP24A1 on the risk of PE. This case-control study genotyped three SNPs of CYP24A1 (rs2762934, rs1570669 and rs6068816) from 139 PE patients and 372 healthy men using Agena MassARRAY platform. Collected data was then processed in SPSS 18.0. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated in logistic regression analysis to evaluate the associations between CYP24A1 polymorphisms and the PE risk. The results suggested that allele A of rs1570669 was significantly associated with the increased PE risk (OR=1.38, 95% CI=1.04-1.84, P=0.026). Meanwhile, we also identified rs1570669 as a risk factor of PE under the additive model (OR=1.47, 95% CI=1.02-2.11, P=0.039) by comparing the genotypic distributions between cases and controls, and genotype AA of rs1570669 was detected to be significantly related with an increased risk of PE under the codominant model (OR=2.26, 95% CI=1.06-4.83, P=0.036). This study is the first to proved that the genetic variants of CYP24A1 played essential role in affecting the susceptibility to PE in Chinese Han.

Study of the role of microRNAs 16 and 135a in patients with lifelong premature ejaculation receiving fluoxetine daily for 3 months: A prospective case control study.

We aimed to determine the level of miRNAs 16 and 135a in lifelong premature ejaculation (LPE) patients versus controls. Moreover, we evaluated the potential interplay between the studied miRNAs and fluoxetine in these patients after utilizing fluoxetine daily for 3 months. The study involved 60 consecutive LPE patients and 20 healthy age matched individuals as controls. The median miRNA16 was significantly higher in the controls (1.02) compared to the patients (0.31) (p < 0.001). Moreover, the median miRNA-135a was significantly higher in the controls compared to the patients 1.02 and 0.35, p < 0.001, respectively. In addition, the median pre-treatment miRNA16 in the responders was 0.29 that significantly increased to 0.66 (p < 0.001). The median pre-treatment miRNA-135a in the responders was 0.27 that significantly increased to 0.65 (p < 0.001). Furthermore, considering EXP(ß) for the odds ratio evaluation, with a 95% degree of confidence, a 1 fold increase in pre-treatment miRNA 135a fold change decreases the odds for being responsive to SSRI by 0.028. Meanwhile, there was non-significant association between fluoxetine responsiveness and age, pre-treatment miRNA 16, pre-treatment PEDT and pre-treatment IELT. The current study had shown that a lower pre-treatment miRNA 135a was significantly associated with response to fluoxetine.

[Correlation of lifelong premature ejaculation with 5-HT system gene polymorphism].

Premature ejaculation is one of the common male sexual dysfunction diseases. Lifelong premature ejaculation (LPE), characterized by an early onset and a long course of disease, has a variety of negative effects on men. The pathogenesis of LPE has not been clarified, but it is believed to be related to the regulation of 5-HT and the 5-HT1a and 5-HT2c receptors from the perspective of the theory of 5-HT system neurotransmitter disorder. Current studies indicate that the 5-HT transporter gene-linked polymorphic region (5-HTTLPR), 5-HT1a receptor gene polymorphism and 5-HT2c receptor gene polymorphism may be associated with the development of and drug effect on LPE. This article reviews the current studies on the development of LPE, effects of medication and 5-HT system gene polymorphism, and discusses the correlation of 5-HT system gene polymorphism with the development of LPE and effects of medication.

Endogenous Deficiency of Brain-Derived Neurotrophic Factor Induces the Downregulation of Tryptophan Hydroxylase-2 Expression in Raphe Nuclei of Rapid Ejaculator Rats.

BACKGROUND: Premature ejaculation (PE) is one of the most common ejaculatory disorders. Recent studies have suggested a close relationship between the serotonin (5-hydroxytryptamine [5-HT]) system and brain-derived neurotrophic factor (BDNF), raising the question of whether BDNF plays a role in ejaculation regulation. To our knowledge, no previous studies have explored BDNF level of the central nervous system in ejaculatory disorders. At the same time, the interaction of central BDNF and 5-HT systems has not been undertaken in ejaculation regulation field. AIM: The aim of this study was to investigate the interaction between BDNF and 5-HT levels in raphe nuclei which contains the serotonergic neurons in a rat animal model with different ejaculatory behavior. METHODS: Eighteen male rats were selected and classified as "sluggish," "normal," and "rapid" ejaculators on the basis of ejaculation frequency during copulatory behavioral testing. BDNF and 5-HT levels were determined by enzyme-linked immunosorbent assay (ELISA). Real-Time Quantitative PCR and Western blot analyses were used to measure the mRNA level of Tryptophan Hydroxylase-2 (TPH2) gene and the expression of TPH2 protein (the rate-limiting enzyme in central 5-HT synthesis) in raphe nuclei, respectively. OUTCOMES: Male rat sexual behavior, the levels of BDNF and 5-HT in raphe nuclei of rats with different ejaculatory behavior, the mRNA level of gene encoding TPH2 and the expression of TPH2 protein in raphe nuclei. RESULTS: The primary finding of our study was that BDNF concentration was significantly decreased in raphe nuclei of rapid ejaculators. There was a strong positive correlation between the levels of BDNF and 5-HT (r = 0.944, P < .001). Further results showed that decreased TPH2 gene expression accompanied by TPH2 protein was shown in rapid ejaculators with lower BDNF level. CLINICAL IMPLICATIONS: With refinement of current knowledge, BDNF may eventually serve as a promising biomarker in patients with PE. STRENGTHS & LIMITATIONS: There are no previous studies examining the interaction of the brain BDNF and 5-HT in ejaculation regulation field. The main limitation is the limited sample size. CONCLUSION: BDNF may act via increasing the synthesis of central 5-HT in the process of ejaculation regulation. Our results suggest lack of endogenous BDNF induces the downregulation of TPH2 gene expression and the decrease of 5-HT synthesis in raphe nuclei of rapid ejaculator rats. Huang Y, Peng D, Geng H, et al. Endogenous Deficiency of Brain-Derived Neurotrophic Factor Induces the Downregulation of Tryptophan Hydroxylase-2 Expression in Raphe Nuclei of Rapid Ejaculator Rats. J Sex Med 2021;18:1491-1499.

A comprehensive assessment of genetic variation in serotonin transporter gene (5-HTTLPR+rs25531) and the response to dapoxetine in Chinese patients with premature ejaculation.

This study was to explore whether serotonin transporter gene-linked polymorphic region polymorphisms (5-HTTLPR+rs25531) influence the response to dapoxetine treatment in a Chinese population with premature ejaculation (PE). 112 patients with PE re-enrolled from our previous study received dapoxetine monotherapy. At the endpoint, patients with S'S' had a significant increased risk of nonresponse compared with L' carriers (p < .001). The improvement in S'S' genotype was significantly lower in premature ejaculation profile (PEP) items of 'control over ejaculation' (p = .035) and 'distress related to ejaculation' (p = .017) than that in L' carriers. As to clinical global impression of change (CGIC), results in S'S' subjects showed significantly lower scores (p = .008) and a less satisfaction rate reporting at least 'better' (p = .020) compared with L' carriers. Moreover, our findings suggested that patients with S'S' were more likely to develop adverse effects (AEs) compared with L' carriers (p = .040). This study suggests that PE patients bearing the S'S' genotype have an inferior comprehensive efficacy and safety of dapoxetine treatment, which consist of poorer response in IELTs, less improvement in patient-reported outcome (PRO) measures and greater incidence of AEs, than L' carriers. Variants of triallelic 5-HTTLPR may play a major role as a predictor of treatment response to dapoxetine.

Rs9303628 and rs2054847 of SLC6A4 are protective factors for the onset of lifelong premature ejaculation among the Chinese population.

The purpose of this study was to investigate whether the polymorphisms of SLC6A4 gene affect the occurrence of lifelong premature ejaculation (LPE). In this case-control study, Agena MassARRAY was used to genotype SLC6A4 polymorphisms of 91 LPE patients and 362 controls. Then, genetic model and haplotype analysis were utilised to explore the correlation between SLC6A4 polymorphisms and LPE risk. The results showed that allele T, genotype T/T and C/T-T/T of rs9303628 were significantly correlated with a decreased risk of LPE in allele (p = .009), co-dominant (p = .025) and dominant (p = .014) model respectively. Allele T and genotype C/T-T/T of rs2054847 reduced the risk of LPE in co-dominant (p = .015) and dominant (p = .030) models respectively. Furthermore, there was a significant correlation between Ars9303628 Crs2054847 haplotype and the decreased the risk of LPE (p = .010). In conclusion, this study firstly proved that the presence of rs9303628 and rs2054847 in SLC6A4 gene was a protective factor for the occurrence of LPE in the Chinese Han population.

Erectile Dysfunction in Young Men: Testosterone, Androgenic Polymorphisms, and Comorbidity With Premature Ejaculation Symptoms.

BACKGROUND: The association between erectile dysfunction (ED), free testosterone (T), and androgenic genetic polymorphisms is still unclear. As most studies in the field have focused on older (>40 y.o.) men, data from young men is scarce. In addition, the clinically observed comorbidity between ED and premature ejaculation (PE) has not been explained. AIM: The aim of the present study was 3-fold: to assess in a sample of young men (1) the association between ED and T; (2) the role of androgenic genetic polymorphisms in the aforementioned association; and (3) comorbidity between ED and PE symptoms. METHODS: Statistical analyses were performed on a population-based sample of 2,302 Finnish men, (Mage = 26.8 years). Hormone samples were available from 317 men, and genotype information was available from a minimum of 1,144 men depending on genetic locus. For twin analyses, the sample contained 533 male individuals from opposite-sex fraternal twin pairs, 491 identical male individuals (110 complete pairs), 493 male individuals from male fraternal twin pairs (92 complete pairs), and 658 siblings of twins. OUTCOMES: The main outcome measure includes association between levels of salivary T and ED, main effects of the androgen-related genetic polymorphisms on ED scores. Bivariate twin models of PE and ED were fitted to elucidate possible shared etiology. RESULTS: We found no significant association between T levels and ED and no significant main effects of the androgenic genetic polymorphisms on ED. We found no evidence suggesting that any of the genetic polymorphisms would moderate the association between T and ED symptoms. We found shared unique environmental influences between PE and ED (rE = .28). CLINICAL TRANSLATION: Obtained data suggest that ED has T-independent causes and that any comorbidity between PE and ED is not explained by a set of genes affecting both phenotypes. STRENGTHS & LIMITATIONS: First, the sample size for both parts of the study was relatively small, which may make some statistical analyses underpowered. Furthermore, as the sample was a population-based sample of relatively young men, the number of clinically relevant ED cases was low. Second, some concerns about T derived from saliva exist because saliva sampling comes with increased risks of error particularly because saliva samples are more vulnerable to contamination. CONCLUSION: We found no significant association between free T levels, androgenic genetic polymorphisms, and ED in the younger age cohort. Twin analysis suggested a common nonshared environmental component in PE and ED. Zhuravleva1 ZD, Johansson A, Jern P. Erectile Dysfunction in Young Men: Testosterone, Androgenic Polymorphisms, and Comorbidity With Premature Ejaculation Symptoms. J Sex Med 2021;18:265-274.

Association between the serotonin transporter linked polymorphic region and lifelong premature ejaculation: An updated meta-analysis of case-control studies.

Previous studies on the association between serotonin transporter linked polymorphic region (5-HTTLPR) polymorphism and premature ejaculation (PE) have led to inconsistent results. The purpose of the present meta-analysis was to examine whether 5-HTTLPR polymorphism is associated with PE susceptibility.All eligible studies were searched and acquired from PubMed, Embase, Science Direct, CNKI, and Wanfang databases according to inclusion and exclusion criteria. Odds ratios (ORs) with 95% confidence intervals (CIs) were computed to assess the strength of the association between 5-HTTLPR polymorphism and PE. In addition, heterogeneity test, publication bias and sensitivity analysis were also conducted.Firstly, the association were observed in 8 studies (L vs S: OR = 0.74, 95% CI = 0.63-0.87; LL vs SS: OR = 0.61, 95% CI = 0.44-0.83; SL vs SS: OR = 0.73, 95% CI = 0.55-0.96; LL + SL vs SS: OR = 0.67, 95% CI = 0.52-0.86; LL vs SL + SS: OR = 0.72, 95% CI = 0.55-0.92). When the 2 studies not in Hardy-Weinberg equilibrium (HWE) were omitted, a positive association could only be observed between the 5-HTTLPR polymorphism and PE in allele contrast model (L vs S: OR = 0.81, 95% CI = 0.67-0.98). In the stratified analysis by subgroup, significantly associations were also found between PE and 5-HTTLPR polymorphism in Caucasians but not Asians (L vs S: OR = 0.79, 95% CI = 0.63-0.98; LL + SL vs SS: OR = 0.67, 95% CI = 0.46-0.96).Our meta-analysis demonstrated that the 5-HTTLPR polymorphism was associated with the susceptibility to PE in the Caucasian population. Compared with S allele, L allele is likely to be less susceptible to PE.

Gene Variants in Premature Ejaculation: Systematic Review and Future Directions.

INTRODUCTION: A growing number of genetic association studies have been performed to investigate the association between the genetic susceptibility alleles and the risk of premature ejaculation (PE); however, the results remain inconclusive. OBJECTIVES: This systematic review aimed: (i) to determine whether an association exists between gene(s) or allelic variant(s) and PE; (ii) to assess whether the associations are consistent across studies in magnitude and direction, and (iii) to identify any limitation, gap, or shortcoming in the included studies. METHODS: The literature search was conducted in PubMed, MEDLINE, Scopus, Cochrane Library, EMBASE, Academic Search Complete, Google Scholar, and CINAHL databases. RESULTS: Different gene variants associated with PE were assessed. 25 genetic association studies met the inclusion criteria that investigated 11 genes, 2,624 men with PE compared with 9,346 men as controls, twins, and siblings. 19 studies demonstrated a significant association with PE, whereas 4 studies denied such a relationship. SLC6A4 gene polymorphism was investigated in 11 studies (7 studies demonstrated a significant relationship with PE, and 4 studies denied such a relationship). Dopamine transporter gene (DAT1) polymorphism was investigated in 4 studies exhibiting a significant relationship. Androgen receptor gene polymorphisms were investigated in 2 studies, 1 with a significant relationship and the other with a non-significant relationship. Oxytocin gene polymorphisms and tryptophan hydroxylase 2 gene polymorphisms were investigated in 2 studies with a significant relationship. CONCLUSION: While this review has highlighted several genes that may be potentially associated with PE such as SLC6A4, limitations such as variance in study methods, lack of robust findings, small sample sizes, lack of reproducibility, quality of reporting, and quality of assessment remain a major concern. Further efforts such as standardizing reporting, exploring complementary designs, and the use of genome-wide association studies technology are warranted to test the reproducibility of these early findings. Mostafa T, Abdel-Hamid IA, Taymour M, et al. Gene Variants in Premature Ejaculation: Systematic Review and Future Directions. Sex Med Rev 2020;8:586-602.

5HT-1A receptor polymorphism effects ejaculatory function in Egyptian patients with lifelong premature ejaculation.

INTRODUCTION AND OBJECTIVES: Lifelong premature ejaculation (LPE) is identified as the inability to delay ejaculation for more than 1min after vaginal penetration occurring on all or almost all sexual experiences together with feelings of frustration of both the patient and his partner with avoidance of sexual intimacy. Recently, a role for (HTR1A)-C (1019) G gene polymorphism in patients with LPE was postulated. MATERIALS AND METHODS: Three hundred and fifty participants were prospectively enrolled in this study. They were recruited from the outpatient clinic of Andrology & STDs Department Cairo University from December 2015 to January 2017. Two hundred and forty-five of them were suffering from lifelong premature ejaculation joined this study, in addition to 105 controls. We instructed the wives of the patients to measure the intra-vaginal ejaculation latency time (IELT) of the first intercourse only using a stopwatch for 1 month. Genotyping was performed at the end of the study. RESULTS: The results showed that the majority of the patients were CG, while; the controls were GG. This difference revealed a statistically significant association (p-value<0.001). A highly significant statistical association was found between the studied gene polymorphisms and the IELT among cases (p-values=0.001). CONCLUSION: The study replicated the potential role of 5HT-1A receptor gene polymorphisms in patients with lifelong premature ejaculation.

[Correlation of 5-hydroxytryptamine transporter gene-linked polymorphic region with lifelong premature ejaculation: Progress in studies].

Premature ejaculation (PE), as one of the most common male sexual dysfunctions, has a serious negative impact on the sexual satisfaction of the patients and their sexual partners. Lifelong PE is a most common type and a current focus of research as well. The etiology and pathogenesis of this disease are not yet clear and genetic factors are considered to be closely related to lifelong PE. Studies show that the 5-hydroxytryptamine transporter (5-HTT) gene plays an important role in the development and progression of lifelong premature ejaculation and the 5-HTT-linked polymorphic region (5-HTTLPR) has attracted much attention in recent years. This article presents an overview on the correlation between 5-HTTLPR and lifelong PE.

Serotonin transporter (5-HTTLPR) genotypes and trinucleotide repeats of androgen receptor exert a combinatorial effect on hormonal milieu in patients with lifelong premature ejaculation.

Premature ejaculation is one of the most common sexual disorders in men due to uncontrolled modulation of spinal reflexes controlled by cortico-limbic centers in the brain. In this study, we investigate the combinatorial effects of trinucleotide repeats of androgen receptor and allelic variants of the 5-HTTLPR gene on sex steroids, hypophyseal hormones, sexual performance, and premature ejaculation assessment parameters among evidence-based lifelong premature ejaculation subjects. A total of 271 outpatients (age 26.6 ± 1.9) consulting for evidence-based lifelong premature ejaculatory dysfunction were selected in this study. The control group consists of 155 men with normal IELT (>4 min). The study revealed that the subjects who have the highest (≥26) CAG stretches depicted a significantly higher serum oxytocin levels (102.1 pg/ml; n = 126, p < 0.001) compared with the control group (71.2 pg/ml; n = 75, p = <0.001) and patients which have medium (22-25) and short (≤21) CAG stretches (76.63 ng/ml; n = 64, p < 0.001 vs. 77.4 ng/ml; n = 81, p < 0.001). Almost 33 (26.1%) lifelong premature ejaculatory patients had AR variant of longer (≥26) CAG repeats was homozygous for S alleles (SS), 45 (35.7%) was homozygous for L allele (LL), and 48 (38%) had the L/S or S/L genotype of 5-HTTLPR gene. Homozygous (SS) alleles have a significant positive correlation (r = 0.44, p < 0.0001) with the high score of BDI-II (39.1, n = 126, p < 0.001). However, LL alleles have shown a significant positive correlation with PEDT (r = 0.46, p < 0.001) and negative correlation with self-estimated IELT and intercourse satisfaction (r = -0.35, p < 0.001). The innovative study design elaborates that androgen receptor trinucleotide repeats and 5-HTTLPR genotypes have combinatorial impact on hormonal milieu and sexual function regarding evidence-based lifelong premature ejaculatory dysfunction patients.

Study of the prevalence of 5 HT-2C receptor gene polymorphisms in Egyptian patients with lifelong premature ejaculation.

We investigated the prevalence of 5HT2C receptor gene polymorphisms in Egyptian patients with lifelong premature ejaculation. A total of 350 participants were enrolled in a prospective study. Two hundred and forty-five cases with lifelong premature ejaculation joined this study, in addition to 105 controls. We instructed the partners of the cases to measure the IELT of the first intercourse only using a stopwatch for 1 month. Genotyping was carried out at the end of the study. The results showed that the majority of the patients and controls were Cys/Cys. A highly significant statistical association was found between the studied gene polymorphisms and IELT among cases (p-values = .009). The study emphasised the potential role of 5HT2C receptor gene polymorphisms in patients with lifelong premature ejaculation.

Preliminary Evidence for an Association Between Variants of the Catechol-O-Methyltransferase (COMT) Gene and Premature Ejaculation.

BACKGROUND: Studies have suggested that dopamine plays a role in the neurobiological mechanism that triggers ejaculation, leading scientists to hypothesize that dopamine-related genetic polymorphisms could contribute to symptoms of premature ejaculation (PE). AIM: To investigate associations between dopamine receptor and catechol-O-methyltransferase (COMT; an enzyme involved in the catabolism of dopamine) gene-linked polymorphisms and PE. METHODS: PE status in patient groups was determined by clinical diagnosis performed by a physician specializing in sexual medicine. Self-reported PE symptoms from a validated questionnaire also were reported. Saliva samples were collected from 149 patients with PE and 1,022 controls from a population-based sample. In total, we tested associations between PE and 11 single-nucleotide polymorphisms in the dopamine receptor D1, D2, and D3 genes and in the COMT gene. OUTCOMES: We found no associations between dopamine receptor gene polymorphisms and PE, but 2 COMT-linked loci (rs4680 and rs4818) had significant associations after correction for multiple testing. RESULTS: 1 COMT gene-linked locus that was associated with PE symptoms in the present study, rs4680, is a well-documented functional polymorphism that causes a valine-to-methionine substitution. The other polymorphism, rs4818, is in high linkage disequilibrium with the rs4680 locus, indicating that they capture the same effect. Surprisingly, the rs4680 variant that was statistically significantly more prevalent in the PE group (ie, the valine-encoding allele) has been associated with higher enzymatic activity and therefore lower synaptic dopamine levels. CLINICAL TRANSLATION: Drugs targeting the dopaminergic system could affect PE symptoms. STRENGTHS AND LIMITATIONS: No replication sample was available for the present study; thus, our findings should be interpreted with caution. Moreover, a limitation of our study is the small sample in the context of genetic association studies (although it should be mentioned that genetically informative samples with phenotypic information about PE symptoms are scarce, and most previous genetic association studies of PE have used samples of similar or smaller size). However, our results are plausible: we report an association between one of the most extensively studied and understood genetic polymorphisms in psychiatric research and PE, and our results are in line with the long-standing hypothesis that dopamine influences human ejaculatory function. CONCLUSIONS: We report an association between 2 COMT gene-linked loci and PE symptoms, but our results should be treated with caution until independently replicated. Jern P, Johansson A, Strohmaier J, et al. Preliminary Evidence for an Association Between Variants of the Catechol-O-Methyltransferase (COMT) Gene and Premature Ejaculation. J Sex Med 2017;14:1558-1565.