CYP1A1 polymorphism in adolescents with polycystic ovary syndrome

Genic-intergenic polymorphisms of CYP1A genes and their clinical impact

The humancytochrome P450 1A (CYP1A) subfamily genes, CYP1A1 and CYP1A2, encoding monooxygenases are critically involved in biotransformation of key endogenous substrates (estradiol, arachidonic acid, cholesterol) and exogenous compounds (smoke constituents, carcinogens, caffeine, therapeutic drugs). This suggests their significant involvement in multiple biological pathways with a primary role of maintaining endogenous homeostasis and xenobiotic detoxification. Large interindividual variability exist in CYP1A gene expression and/or catalytic activity of the enzyme, which is primarily due to the existence of polymorphic alleles which encode them. These polymorphisms (mainly single nucleotide polymorphisms, SNPs) have been extensively studied as susceptibility factors in a spectrum of clinical phenotypes. An in-depth understanding of the effects of polymorphic CYP1A genes on the differential metabolic activity and the resulting biological pathways is needed to explain the clinical implications of CYP1A polymorphisms. The present review is intended to provide an integrated understanding of CYP1A metabolic activity with unique substrate specificity and their involvement in physiological and pathophysiological roles. The article further emphasizes on the impact of widely studied CYP1A1 and CYP1A2 SNPs and their complex interaction with non-genetic factors like smoking and caffeine intake on multiple clinical phenotypes. Finally, we attempted to discuss the alterations in metabolism/physiology concerning the polymorphic CYP1A genes, which may underlie the reported clinical associations. This knowledge may provide insights into the disease pathogenesis, risk stratification, response to therapy and potential drug targets for individuals with certain CYP1A genotypes.

Mutational Landscape Screening Through Comprehensive In Silico Analysis for Polycystic Ovarian Syndrome-Related Genes

Polycystic ovary syndrome (PCOS) is a multifactorial endocrinopathy of indistinguishable etiopathogenesis that is liable to entail genetic and environmental machinery synergistically interacting with its phenotypic expression. It has been hypothesized that the environment secondarily interacts with genes to define the quantifiable phenotype in a primary, genetically determined, hyper-androgenic ovarian defect. The severity and prevalence of the disease are escalating due to uncontrolled diet and lifestyle, the influence of multiple environmental factors as well as genetic disorders. Many candidate genes have been identified to be one of the causes of PCOS. Different studies have been carried out to find the genetic correlation of PCOS. The mutational landscape analysis scans the entire genes for SNPs which usually occurs more frequently in patients and not in healthy individuals. In this study, an extensive computational analysis of all reported nsSNPs of the 27 selected PCOS-related genes was performed to infer the most pathogenic forms associated with PCOS. As a result, 28 genetic variants from 11 genes were predicted to be most harmful. Results of the present study can be useful for building an integrative genotype-phenotype database for further studies.

Association Analysis of CYP11A1 Variants with Polycystic Ovary Syndrome: a Case-Control Study from North India

The most common multifactorial endocrine disorder in females of reproductive age is polycystic ovary syndrome (PCOS), affecting about 5-10% of females worldwide and 9.3% of females in India. Androgen excess in PCOS is caused as a result of defects in steroidogenesis genes. CYP11A1 is an imperative marker in the steroid synthesis pathway, and the altered expression of CYP11A1 has been reported to disrupt the synthesis of steroids and hence conferring risk for the development of PCOS. The present study aimed to analyze genetic variants (rs11632698, rs4077582, rs4887139) of CYP11A1 with PCOS from North India. The study included 270 PCOS females diagnosed according to Rotterdam 2003 criteria and 270 age-matched healthy non-PCOS females. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used for the genotypic analysis of the selected genetic variants. Association analysis of biochemical parameters (cholesterol, triglyceride, high-density lipoprotein) and anthropometric measurements with PCOS cases was done. The genetic variants of CYP11A1 (rs11632698, rs4077582, and rs4887139) demonstrated significant association with PCOS cases (p=1.0E-12, p=3.0E-3, p=1.0E-2, respectively). Binary logistic regression revealed that the dominant model of rs11632698 conferred 2.0 risk, and dominant as well as the co-dominant model of rs4887139 conferred risk of 2.2 and 2.4 fold, respectively, towards the progression of PCOS. The overall mean triglyceride levels were elevated, and mean HDL levels were lower in PCOS cases as compared to threshold values. The significant association of studied genetic variants suggested the important role of CYP11A1 in susceptibility to PCOS. The study was the first of its kind from our region and provided baseline data of genetics of PCOS.

CYP1A1 gene (6235T<C) polymorphism as a risk factor for polycystic ovarian syndrome among Egyptian women

This case-control study was carried out to examine the association between CYP1A1 gene (6235T<C) polymorphism among Egyptian women with polycystic ovarian syndrome (PCOS). One hundred and twenty women with PCOS, as well as 120 apparently healthy women as controls, were included in this study. Blood samples were collected on the second or third day of the menstrual cycle for laboratory work-up. CYP1A1 gene (6235T<C) polymorphism was determined using restriction enzyme fragment length polymorphism - polymerase chain reaction (RFLP-PCR) technique. Women who carried the TC and CC genotypes showed insignificant increase in risk (1.4 and 2.7, respectively) for developing PCOS (p = 0.331 and p = 0.124, respectively). The risk showed a significant association among PCOS women with ovarian sonographic stigmata of polycystic ovaries (PCO) who carried the TC genotype (Odds Ratio (OR) = 1.92, p = 0.032), as well as among carriers of the CC genotype (OR = 4.2, p = 0.048). Both TC and CC genotypes were significantly associated with the ovarian volume (p < 0.001) and abdominal obesity (p = 0.025), while no associations were shown with the hormonal profile. In conclusion, both TC and CC genotypes of the CYP1A1 gene showed increased susceptibility to PCOS. CYP1A1 gene polymorphism may affect the folliculogenesis and the hormonal status along with other risk factors leading to the development of the full picture of PCOS.

Genetic association study from North India to analyze association of CYP19A1 and CYP17A1 with polycystic ovary syndrome

PURPOSE

Polycystic ovary syndrome (PCOS) is a complex multifactorial endocrine disorder affecting approximately 5-10% of women of reproductive age. Affected women have menstrual disturbances due to anovulation, infertility, and hyperandrogenism. Ovarian androgen overproduction is the key physiopathologic feature of PCOS. A number of genes encoding major enzymes of the androgen metabolic pathways, such as HSD17B6, CYP19A1, CYP11A1, CYP17A1, and INSR, have been examined. Very few studies have been done in North India. There is an increasing prevalence of PCOS in women in Punjab and it is the leading cause of female infertility. In view of the strong evidence implicating the importance of CYP19A1 and CYP17A1 in androgen metabolic pathways, we investigated the association of rs700519, rs2414096, and rs743572 (- 34T>C) polymorphisms on susceptibility of developing PCOS, in North India.

METHODS

A total of 500 subjects (women of reproductive age) including 250 PCOS cases and 250 healthy age-matched controls were included in the present study. DNA was extracted from venous blood for all samples, and association analysis for rs2414096, rs700519, and rs743572 was done by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique. Lipid profile was done using a biochemical analyzer and body mass index (BMI) was measured for all cases. Statistical analysis was performed.

RESULTS

Significant association of - 34T>C polymorphism of CYP17A1 was found with PCOS (p = 0.0005). BMI was statistically different between PCOS cases and controls (p = 0.000). Triglycerides were high in PCOS women. Variations of CYP19A1 were not statistically significant with PCOS.

CONCLUSIONS

These data suggest that - 34T>C polymorphism in CYP17A1 is associated with PCOS in North India. No polymorphism of CYP19A1 was found to be associated.

Potential Positive Association between Cytochrome P450 1A1 Gene Polymorphisms and Recurrent Pregnancy Loss: a Meta-Analysis

In order to discover the potential genetic risks associated with recurrent pregnancy loss (RPL), this meta-analysis was conducted to assess the association between CYP1A1 gene polymorphism and RPL. Studies were retrieved from the databases PubMed, Embase, HuGENet, and CNKI. Four models were then applied. Seven studies, including three datasets for the rs1048943 and five for the rs4646903 single-nucleotide polymorphism (SNP), were included in this analysis, involving 613 cases and 398 controls for the rs1048943; and 864 cases and 842 controls for the rs4646903 SNP. After comprehensive analysis, we found that rs4646903 was significantly associated with RPL [recessive (OR = 1.72, 95%CI: 1.13-2.61); codominant (CC vs TT; OR = 1.74, 95%CI: 1.12-2.71), (CC vs CT; OR = 1.67, 95%CI: 1.07-2.62) and allele analysis (OR = 1.27, 95%CI: 1.07-1.50)]. In the following subgroup analysis, a positive association was also discovered among people of Asian descent, especially South Asians. However, there was no obvious association between rs1048943 and RPL. In summary, our results suggest that CYP1A1 gene polymorphism (particularly for rs4646903) might be associated with RPL risk, especially among South Asians. Further studies are required to confirm this association.

CYP1A1 and GSTP1 gene variations in breast cancer: a systematic review and case-control study

In first part of this study, a systematic review was designed to explore the involvement of CYP1A1 and GSTP1 genes in breast cancerogenesis. Based on systematic review, we designed a study to screen CYP1A1 and GSTP1 genes for mutation and their possible association with breast carcinogenesis. A total of 400 individuals were collected and analyzed by PCR-SSCP. After sequence analysis of coding region of CYP1A1 we identified eleven mutations in different exons of respective gene. Among these eleven mutations, ~3 folds increased breast cancer risk was found associated with Asp82Glu mutation (OR 2.99; 95% CI 1.26-7.09), with Ser83Thr mutation (OR 2.99; 95% CI 1.26-7.09) and with Glu86Ala mutation (OR 3.18; 95% CI 1.27-7.93) in cancer patients compared to controls. Furthermore, ~4 folds increase in breast cancer risk was found associated with Asp347Glu, Phe398Tyr and 5178delT mutations (OR 3.92; 95% CI 1.35-11.3) in patients compared to controls. The sequence analysis of GSTP1 resulted in identification of total five mutations. Among these five mutations, ~3 folds increase in breast cancer risk was observed associated with 1860G>A mutation, with 1861-1876delCAGCCCTCTGGAGTGG mutation (OR 2.70; 95% CI 1.10-6.62) and with 1861C>A mutation (OR 2.97; 95% CI 1.01-8.45) in cancer patients compared to controls. Furthermore, ~5 folds increase in breast cancer risk was associated with 1883G>T mutation (OR 4.75; 95% CI 1.46-15.3) and ~6 folds increase in breast cancer risk was found associated with Iso105Val mutation (OR 6.43; 95% CI 1.41-29.3) in cancer patients compared to controls. Our finding, based on systematic review and experimental data suggest that the polymorphic CYP1A1 and GSTP1 genes may contribute to risk of developing breast cancer.

Association between 3801T>C polymorphism of CYP1A1 and idiopathic male infertility risk: a systematic review and meta-analysis

BACKGROUND

Epidemiological studies have evaluated the association between 3801T>C polymorphism of CYP1A1 gene and the risk for idiopathic male infertility, but the results are inconclusive. We aimed to derive a more precise estimation of the relationship by conducting a meta-analysis of case-control studies.

METHODS

This study conformed to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. PubMed, Embase and CNKI databases were searched through November 2013 to identify relevant studies. Pooled odds ratios with 95% confidence intervals were used to assess the strength of the association between CYP1A1 3801T>C polymorphism and idiopathic male infertility risk. Q-test was performed to evaluate between-study heterogeneity and publication bias was appraised using funnel plots. Sensitivity analyses were conducted to evaluate the robustness of meta-analysis findings.

RESULTS

Six studies involving 1,060 cases and 1,225 controls were included in this meta-analysis. Overall, significant associations between 3801T>C polymorphism and idiopathic male infertility risk were observed in allelic comparison (OR = 1.36, 95% CI: 1.01-1.83), homozygous model (OR = 2.18, 95% CI: 1.15-4.12), and recessive model (OR = 1.86, 95% CI: 1.09-3.20), with robust findings according to sensitivity analyses. However, subgroup analyses did not further identify the susceptibility to idiopathic male infertility in all comparisons. Funnel plot inspections did not reveal evidence of publication bias.

CONCLUSIONS

The current meta-analysis provides evidence of a significant association between CYP1A1 3801T>C polymorphism and idiopathic male infertility risk. Considering the limitation inherited from the eligible studies, further confirmation in large-scale and well-designed studies is needed.

Common polymorphisms in the CYP1A1 and CYP11A1 genes and polycystic ovary syndrome risk: a meta-analysis and meta-regression

AIM

Increasing scientific evidences suggest that common polymorphisms in the CYP1A1 and CYP11A1 genes may contribute to the development and progression of polycystic ovary syndrome (PCOS), but many existing studies have yielded inconclusive results. The aim of this study was to perform a meta-analysis of published studies on the associations between common polymorphisms in the CYP1A1 and CYP11A1 genes and susceptibility to PCOS.

METHODS

An extensive literature search for relevant studies was conducted on PubMed, Embase, Web of Science, Cochrane Library, and CBM databases from their inception through 1 June, 2013. This meta-analysis was performed using the STATA 12.0 software. The crude risk ratio (RR) with 95% confidence interval was calculated.

RESULTS

Thirteen case-control studies were included in this meta-analysis with a total of 1,571 PCOS cases and 1,918 healthy controls. Our meta-analysis revealed that CYP1A1 MspI (rs4646903 T > C) polymorphism may increase the risk of PCOS, especially among Caucasian populations. Furthermore, CYP11A1 microsatellite [TTTA]n repeat polymorphism also showed significant associations with increased risk of PCOS among Caucasian populations. However, there was no statistically significant association between CYP1A1 Ile462Val (rs1048943 A > G) polymorphism and PCOS risk.

CONCLUSION

Our meta-analysis suggests that CYP1A1 MspI and CYP11A1 microsatellite [TTTA]n repeat polymorphisms may contribute to increasing susceptibility to PCOS among Caucasian populations. Detection of common polymorphisms in the CYP1A1 and CYP11A1 genes might be promising biomarkers for the diagnosis and prognosis of PCOS.

CYP1A1 gene polymorphisms and polycystic ovary syndrome risk: a meta-analysis and meta-regression

AIMS

Emerging evidence suggests that common functional polymorphisms in the CYP1A1 gene are involved in the regulation of the activities of cytochrome P450 enzymes, thereby increasing an individual's susceptibility to polycystic ovary syndrome (PCOS), but individually published results are inconclusive. This meta-analysis aimed to derive a more precise estimation of the relationship between CYP1A1 gene polymorphisms and PCOS risk.

METHODS

A literature search of PubMed, Embase, Web of Science, the Cochrane Library, Chinese National Knowledge Infrastructure, Chinese Bio-medicine Database, and Chinese Sci-tech Journals Database (VIP) databases was conducted from inception to March 1, 2013. The crude odds ratio (OR) with 95% confidence interval (CI) were calculated.

RESULTS

Five case-control studies were included with a total of 1,036 subjects, including 521 PCOS cases and 515 healthy controls. Our meta-analysis results indicated that the C variant of the CYP1A1 rs4646903 (T>C) polymorphism was associated with an increased risk of PCOS (allele model: OR=1.62, 95% CI: 1.06-2.48, P=0.025; dominant model: OR=2.37, 95% CI: 1.25-4.48, P=0.008; homozygous model: OR=2.52, 95% CI: 1.17-5.44, P=0.019), especially among the general female population in Turkey and India. However, there was no statistically significant association between the CYP1A1 rs1048943 (A>G) polymorphism and PCOS risk (all P>0.05). No publication bias was detected in this meta-analysis.

CONCLUSION

The current meta-analysis indicates that the CYP1A1 rs4646903 (T>C) polymorphism may contribute to increasing susceptibility to PCOS, especially among the general female population in Turkey and India. However, further studies are still needed to accurately determine whether the CYP1A1 rs1048943 (A>G) polymorphism is associated with PCOS risk.