The relationship between CAG repeat length polymorphism and infertility in Southern Chinese Han women

Sex hormone-related polymorphisms in endometriosis and migraine: A narrative review

Some evidence indicates endometriosis and migraine have a common genetic predisposition in sex-hormone genes, which could have important implications for the treatment of these two heterogenous conditions. To date, the genes responsibility remains unknown. Based on the biological hypothesis that polymorphisms of genes involved in sex-hormone pathways may influence estrogen levels and phenotypes of both disorders, we did a literature search for candidate sex-hormone genes and genes involved in the metabolism of estradiol. The aim was to review the evidence for shared sex-hormone-related polymorphisms between endometriosis and migraine and provide an exhaustive overview of the current literature. We included case-control studies investigating associations between candidate sex-hormone-related genes and the disorders endometriosis and migraine, respectively. Results showed three overlapping sex-hormone-associated polymorphisms in estrogen receptor genes that are associated with both conditions. To confirm possible associations with other sex-hormone genes, larger studies are needed.

The role of androgen receptor CAG repeat polymorphism in androgen excess disorder and idiopathic hirsutism

PURPOSE

The study aimed to investigate whether repeat number in the androgen receptor (AR) gene has any contribution to phenotypes of the disease of androgen excess (polycystic ovary syndrome (PCOS), idiopathic hyperandrogenemia (IHA) and idiopathic hirsutism (IH) in a cohort of Turkish women.

METHODS

Three hundred and fifty-four voluntary premenopausal women (172 healthy controls and 182 patients with androgen excess disorders and idiopathic hirsutism) 18-45 years of age seen at an outpatient endocrine clinic at Erciyes University Hospital between January 2013 and December 2014 were included. All volunteers have undergone physical examination and biochemical evaluation. The polymorphic (CAG)n repeat of the human AR was determined by fragment analyses.

RESULTS

Detailed clinical analyses of the patients ended up with 137 PCOS, 24 IHA, and 21 IH. Pairwise comparisons revealed the CAG repeat number differences between the PCOS and controls (p = 0.005) and IH and controls (p = 0.020). Women with CAG repeat length ≤ 17 had a significantly increased twofold risk for PCOS than those women with > 17 CAG repeats OR: 2.0 (95% CI 1.2-3.3, p = 0.005). Women with CAG repeat length ≤ 17 had a significantly increased threefold risk for IH than those women with > 17 CAG repeats OR: 2.9 (95% CI 1.2-7.3, p = 0.020). When correlation analysis was performed, a weak negative correlation was detected between the short allele and FGS score (r = - 0.131, p = 0.013) and a positive relationship between total testosterone and longer allele in the IHA group (r = 0.425, p = 0.039). Median repeat length of the shorter allele between oligomenorrhea and woman with normal menstrual cycle was found to be statistically significant (p = 0.017).

CONCLUSION

This study indicated that the risk of PCOS and IH is associated with the inheritance of ARs with shorter CAG repeats.

Phenotype and genotype of polycystic ovary syndrome in Asia: Ethnic differences

Polycystic ovary syndrome (PCOS) is a common endocrine disorder in reproductive-aged women, and ethnic diversity has been reported in its manifestation. This review addressed phenotype and genetic studies in Asian women with PCOS. Generally, East Asians are less hirsute, and the hirsutism score cutoff is lower than the Caucasian counterpart. It is not clear whether there are any significant differences in the prevalence or severity of irregular menstruation (IM) or characteristics of polycystic ovary (PCO) across ethnicities. Interestingly, the IM/PCO subgroup is a relatively common phenotype in East Asian patients but not in Caucasian patients. The prevalence of insulin resistance in PCOS patients varies depending on the index used and the cutoff, but women with PCOS showed a higher degree of insulin resistance than those of controls across ethnicities. Lower body mass index (BMI) and lower prevalence of metabolic syndrome were reported in East Asian patients, but despite lower BMI, a comparative study reported that Asian women with PCOS were more likely to have diabetes compared with Caucasian patients, suggesting they also have metabolic complications. Unlike East Asian patients, South Asian patients showed an increased degree of hirsutism, early onset of symptoms, and severe insulin resistance and metabolic risks compared with Caucasians. Genetic components play important roles in the pathogenesis of PCOS, and genome-wide association studies of PCOS suggest that similar genetic risk factors exist between Asian and Caucasian patients. Continuous comparative studies are needed to standardize the diagnosis and management of PCOS across different ethnicities.

The CAG polymorphism in androgen receptor (AR) gene impacts the moral permissibility of harmful behavior in females

The moral permissibility of harm is strikingly varied among individuals. In light of the connection between testosterone levels and utilitarian moral judgment, this study examined to what extent a CAG polymorphism in the androgen receptor gene, a genetic polymorphism with the ability to regulate testosterone function, contributes to individual differences in moral judgment. Four hundred and thirty-nine Chinese Han participants completed permissibility ratings of harm in moral dilemmas and moral transgression scenarios. Results showed a significant association between the CAG polymorphism and moral permissibility of harm in females. Females with more copies of the S allele, which is associated with higher availability of testosterone, were more likely to judge harmful utilitarian acts and unintentionally harmful acts as permissible, while these effects were absent in males. The findings provide the first evidence for a link between the androgen receptor gene and moral judgment and highlight the role of androgens in moral foundations.

Androgen receptor CAG repeats length polymorphism and the risk of polycystic ovarian syndrome (PCOS)

OBJECTIVE

Polycystic ovarian syndrome (PCOS) refers to an inheritable androgen excess disorder characterized by multiple small follicles located at the ovarian periphery. Hyperandrogenism in PCOS, and inverse correlation between androgen receptor (AR) CAG numbers and AR function, led us to hypothesize that CAG length variations may affect PCOS risk.

METHODS

CAG repeat region of 169 patients recruited following strictly defined Rotterdam (2003) inclusion criteria and that of 175 ethnically similar control samples, were analyzed. We also conducted a meta-analysis on the data taken from published studies, to generate a pooled estimate on 2194 cases and 2242 controls.

RESULTS

CAG bi-allelic mean length was between 8.5 and 24.5 (mean = 17.43, SD = 2.43) repeats in the controls and between 11 and 24 (mean = 17.39, SD = 2.29) repeats in the cases, without any significant difference between the two groups. Further, comparison of bi-allelic mean and its frequency distribution in three categories (short, moderate and long alleles) did not show any significant difference between controls and various case subgroups. Frequency distribution of bi-allelic mean in two categories (extreme and moderate alleles) showed over-representation of extreme sized alleles in the cases with marginally significant value (50.3% vs. 61.5%, χ(2) = 4.41; P = 0.036), which turned insignificant upon applying Bonferroni correction for multiple comparisons. X-chromosome inactivation analysis showed no significant difference in the inactivation pattern of CAG alleles or in the comparison of weighed bi-allelic mean between cases and controls. Meta-analysis also showed no significant correlation between CAG length and PCOS risk, except a minor over-representation of short CAG alleles in the cases.

CONCLUSION

CAG bi-allelic mean length did not differ between controls and cases/case sub-groups nor did the allele distribution. Over-representation of short/extreme-sized alleles in the cases may be a chance finding without any true association with PCOS risk.

Association of the CAG repeat polymorphisms in androgen receptor gene with polycystic ovary syndrome: a systemic review and meta-analysis

BACKGROUND

Many studies have reported the associations of polymorphic CAG repeats in androgen receptor (AR) gene with PCOS risk, but with inconsistent results. So, the aim of present meta-analysis was to clarify such inconsistence, so as to provide more conclusive results.

METHODS

PubMed was searched for the eligible reports published until February 2012 without language limitation. The studies reporting the relationship between CAG repeat length and PCOS were selected for the meta-analysis according to the inclusion criteria. Two reviewers independently extracted the data and evaluated the study quality.

PRINCIPAL FINDINGS

As for the relationship between CAG repeat length and PCOS risk, the pooled results showed that the biallelic mean was not significantly different between PCOS and controls (SMD -0.03, 95% CI -0.16-0.10, P=0.603), and that the ORs of PCOS were not demonstrated for the individuals with the biallelic mean less than median (OR 0.96, 95% CI 0.68-1.35, P=0.794), with the short CAG allele (OR 0.94, 95% CI 0.80-1.10, P=0.424), or with the X-weighted biallelic mean (OR 0.81, 95% CI 0.46-1.41, P=0.447). Further, as for the relationship between CAG repeat length and T levels in PCOS patients, the biallelic mean was not significantly different between PCOS patients with high T and those with low T (SMD 0.79, 95% CI -0.12-1.70, P=0.088), while the summary correlation r indicated that the CAG biallelic mean appeared to be positively associated with T levels in PCOS (r 0.20, 95% CI 0.11-0.30, p=0.000).

CONCLUSIONS

This meta-analysis demonstrates no evident association between the CAG length variations in AR gene and PCOS risk, while the CAG length appears to be positively associated with T levels in PCOS patients.

Androgen receptor gene polymorphism and polycystic ovary syndrome

BACKGROUND

Polycystic ovary syndrome (PCOS) is characterized by ovulatory dysfunction and hyperandrogenism. Its etiopathology is not well understood but genetic factors seem to have a role. Polymorphism of the androgen receptor (AR) gene has been associated with different androgen pattern diseases.

OBJECTIVE

To review the association between AR gene polymorphism and PCOS.

SEARCH STRATEGY

A systematic review was performed via PUBMED, EMBASE, and LILACS (up to May 31, 2011).

SELECTION CRITERIA

Studies assessing the presence of the (CAG)(n) polymorphism of the AR gene in at least 2 comparison groups (PCOS and control). Studies that did not contain adequate information were excluded.

DATA COLLECTION AND ANALYSIS

Study characteristics and results were analyzed. Meta-analysis could not be performed because only 2 articles provided odds ratios.

MAIN RESULTS

Ten studies met the inclusion criteria. Three studies reported a correlation between the polymorphism and PCOS; 2 studies linked the disorder to shorter repeats, whereas the other associated it with longer repeats.

CONCLUSION

Polymorphism of the AR gene seems to be a promising biomarker for PCOS because shorter repeats may be linked to the disorder. However, further studies are needed to understand the association fully.

Negative association between androgen receptor gene CAG repeat polymorphism and polycystic ovary syndrome? A systematic review and meta-analysis

A number of studies focusing on the association between the exon 1 CAG repeat polymorphism of the androgen receptor (AR) gene and polycystic ovary syndrome (PCOS) have revealed conflicting results. The current systematic review and meta-analysis was conducted to quantify the strength of the association and to explore potential sources of heterogeneity that may have influenced the results. Studies matched to search terms from PubMed, EMBASE and HuGE Navigator published through to 31 January 2012 were retrieved. Data extraction from the included studies was carried out by two authors independently. Weighted mean differences (WMDs) of biallelic mean and odds ratios (ORs) of alleles and genotypes were pooled for meta-analysis. Sixteen articles reporting on 17 studies were included. In continuous data analysis, the summary WMD was -0.06 (95% confidence interval -0.29 to 0.16). In dichotomous data analysis, we divided the alleles into short and long alleles and calculated the summary ORs. No statistically significant results were identified by different comparison models or different cut-off point definitions. No publication bias was observed in continuous and dichotomous data analysis. In summary, the current systematic review and meta-analysis found that the AR CAG microsatellite repeat polymorphism is unlikely to be a major determining factor in the development of PCOS.