Dopamine D3 receptor polymorphism is not associated with the polycystic ovary syndrome

In-Silico Investigation of Effects of Single-Nucleotide Polymorphisms in PCOS-Associated CYP11A1 Gene on Mutated Proteins

Polycystic ovary syndrome (PCOS) is a reproductive disorder with multiple etiologies, mainly characterized by the excess production of androgens. It is equally contributed to by genes and environment. The CYP11A1 gene is imperative for steroidogenesis, so any dysregulation or mutation in this gene can lead to PCOS pathogenesis. Therefore, nucleotide diversity in this gene can be helpful in spotting the likelihood of developing PCOS. The present study was initiated to investigate the effect of single nucleotide polymorphisms in human CYP11A1 gene on different attributes of encoded mutated proteins, i.e., sub-cellular localization, ontology, half-life, isoelectric point, instability index, aliphatic index, extinction coefficient, 3-D and 2-D structures, and transmembrane topology. For this purpose, initially coding sequence (CDS) and single nucleotide polymorphisms (SNPs) were retrieved for the desired gene from Ensembl followed by translation of CDS using EXPASY tool. The protein sequence obtained was subjected to different tools including CELLO2GO, ProtParam, PHYRE2, I-Mutant, SIFT, and PolyPhen. It was found that out of seventy-eight SNPs analyzed in this project, seventeen mutations, i.e., rs750026801 in exon 1, rs776056840, rs779154292 and rs1217014229 in exon 2, rs549043326 in exon 3, rs755186597 in exon 4, rs1224774813, rs757299093 and rs1555425667 in exon 5, rs1454328072 in exon 7, rs762412759 and rs755975808 in exon 8, and rs754610565, rs779413653, rs765916701, rs1368450780, and rs747901197 in exon 9 considerably altered the structure, sub-cellular localization, and physicochemical characteristics of mutated proteins. Among the fifty-nine missense SNPs documented in present study, fifty-five and fifty-three were found to be deleterious according to SIFT and PolyPhen tools, respectively. Forty-nine missense mutations were analyzed to have a decreasing effect on the stability of mutant proteins. Hence, these genetic variants can serve as potential biomarkers in human females for determining the probability of being predisposed to PCOS.

Explore the potential molecular mechanism of polycystic ovarian syndrome by protein-protein interaction network analysis

Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders prevailing in reproductive age women, present in 3-15% population of women worldwide. Although there are many studies on PCOS, its underlying mechanism remains to be determined. The present study was to construct protein-protein interaction networks based on the potential disease-causing genes for PCOS and characterize the underlying molecular mechanisms of PCOS using the networks. PCOS-associated genes were extracted from DisGeNet and the protein-protein interaction networks (PPIN) of PCOS were constructed using the String Database. Then we utilized MCODE algorithm to analyse the hub-gene modules from the PPIN. Finally, the major biological functions and signaling pathways involved in the hub modules were explored by functional enrichment analysis. A total of 522 candidate genes associated to PCOS were extracted from DisGeNET database. The PPIN constructed using the genes we have collected above included 488 genes and 2767 interaction relationships. Moreover, seven major gene modules were obtained after analyzing the PPIN with the use of MCODE plug-in. The major modules generated were enriched in certain biological functions such as cancer and cell proliferation and apoptosis, regulation of lipid and glucose metabolism, cell cycle and so on. The integrated analysis performed in the current study revealed that these hub modules and their related genes are closely associated to the pathogenesis of PCOS, which may probably provide novel insights for the treatment of PCOS and the study of its latent pathogenic mechanism. The relationship between several of the key genes including ALB, TOP2A, PTGER3, NPB and BRD2 in the modules and PCOS has not been investigated previously and it remains to be verified by further research of large sample, multi-center and multi-ethnic.

The Genetic Basis of the Polycystic Ovary Syndrome: A Literature Review Including Discussion of PPAR-gamma

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder of the women of reproductive age. Familial clustering of PCOS has been consistently reported suggesting that genetic factors play a role in the development of the syndrome although PCOS cases do not exhibit a clear pattern of Mendelian inheritance. It is now well established that PCOS represents a complex trait similar to type-2 diabetes and obesity, and that both inherited and environmental factors contribute to the PCOS pathogenesis. A large number of functional candidate genes have been tested for association or linkage with PCOS phenotypes with more negative than positive findings. Lack of universally accepted diagnostic criteria, difficulties in the assignment of male phenotype, obscurity in the mode of inheritance, and particularly small sample size of the study populations appear to be major limitations for the genetic studies of PCOS. In the near future, utilizing the genome-wide scan approach and the HapMap project will provide a stronger potential for the genetic analysis of the syndrome.

Functional genetic polymorphisms and female reproductive disorders: Part I: Polycystic ovary syndrome and ovarian response

BACKGROUND

The identification of polymorphisms associated with a disease can help to elucidate its pathogenesis, and this knowledge can be used to improve prognosis for women with a particular disorder, such as polycystic ovary syndrome (PCOS). Since an altered response to ovarian stimulation is also a characteristic of the disease, further knowledge about its aetiology could help in defining the parameters that determine the response of an individual to ovarian stimulation.

METHODS

PubMed and EMBASE databases were systematically searched for gene association studies published until the end of August 2007, using search criteria relevant to PCOS and ovarian response to stimulation. Data from additional papers identified through hand searches were also included; 139 publications were reviewed.

RESULTS

Several genes involved in ovarian function and metabolism are associated with increased susceptibility to PCOS, but none is strong enough to correlate alone with susceptibility to the disease, or response to therapy. A single-nucleotide polymorphism in exon 10 of the FSH receptor (FSHR) gene, FSHR p.N680S, was consistently identified as having a significant association with ovarian response to FSH.

CONCLUSIONS

No consistent association between gene polymorphism and PCOS could be identified. The FSHR gene may play a significant role in the success of ovarian stimulation, and can be used as a marker to predict differences in FSHR function and ovarian response to FSH. Genotyping the FSHR p.N680S polymorphism may provide a means of identifying a population of poor responders before in vitro fertilization procedures are initiated.

Genetics of polycystic ovarian syndrome

Polycystic ovarian syndrome is a complex disorder with multiple factors affecting its etiology. Elucidation of specific genes and mode of inheritance remains a significant challenge. Linkage and association studies have resulted in over 50 candidate genes as a source of heritable predisposition; however, small sample sizes and failure to reproduce results have hindered efforts. In addition, low fecundity, lack of a male phenotype, and variation of diagnostic criteria represent unique challenges to discovery of polycystic ovarian syndrome genes. A concerted effort will be necessary to conclusively rule in or rule out candidate genes.

Genetics of polycystic ovary syndrome: searching for the way out of the labyrinth

Polycystic ovary syndrome (PCOS) is a complex and heterogeneous disorder presenting a challenge for clinical investigators. It is the most common endocrine disorder of women in reproductive age, a multifaceted reproductive, cosmetic and metabolic problem, with an enigmatic pathophysiological and molecular basis. Although the familial segregation has been noticed very early in the description of the syndrome and family studies in first-degree relatives of women diagnosed with PCOS reveal clustering of the disease, the genetic studies have not as yet determine the pattern of heredity. Part of the problem in genetic studies has been the lack of uniform criteria for diagnosis, heterogeneity of phenotypic features and the fact that the disorder is only expressed clinically in women during their reproductive years. Even within affected families and between sisters with polycystic ovaries, there is heterogeneity in presentation. However, regardless of diagnostic criteria used to identify profanes and to determine affected status in the kindred, the foundation of genetic studies suggests a strong familial component. Currently, PCOS is considered a polygenic trait that might result from the interaction of susceptible and protective genomic variants under the influence of environmental factors, whose role is under intensive investigation. Candidate genes cover a broad spectrum of an endless list of molecules which participate on every step of reproductive and metabolic pathways of this syndrome. Focused research in identification of these genes may provide valuable information and shed some light on the way out of the genomic labyrinth, elucidating the underlying pathophysiology and aiming at a more efficient therapeutic approach of this complicated endocrine disorder.

The molecular-genetic basis of functional hyperandrogenism and the polycystic ovary syndrome

The genetic mechanisms underlying functional hyperandrogenism and the polycystic ovary syndrome (PCOS) remain largely unknown. Given the large number of genetic variants found in association with these disorders, the emerging picture is that of a complex multigenic trait in which environmental influences play an important role in the expression of the hyperandrogenic phenotype. Among others, genomic variants in genes related to the regulation of androgen biosynthesis and function, insulin resistance, and the metabolic syndrome, and proinflammatory genotypes may be involved in the genetic predisposition to functional hyperandrogenism and PCOS. The elucidation of the molecular genetic basis of these disorders has been burdened by the heterogeneity in the diagnostic criteria used to define PCOS, the limited sample size of the studies conducted to date, and the lack of precision in the identification of ethnic and environmental factors that trigger the development of hyperandrogenic disorders. Progress in this area requires adequately sized multicenter collaborative studies after standardization of the diagnostic criteria used to classify hyperandrogenic patients, in whom modifying environmental factors such as ethnicity, diet, and lifestyle are identified with precision. In addition to classic molecular genetic techniques such as linkage analysis in the form of a whole-genome scan and large case-control studies, promising genomic and proteomic approaches will be paramount to our understanding of the pathogenesis of functional hyperandrogenism and PCOS, allowing a more precise prevention, diagnosis, and treatment of these prevalent disorders.

Le syndrome des ovaires polykystiques en période péri-pubertaire : polymorphisme clinique, biologique, métabolique et génétique

Polycystic ovary syndrome (PCOS) is a common cause of hyperandrogenism in adolescent girls. In its complete post menarchal expression, the syndrome is characterized by the association of typical clinical, biological, and ultrasonographic findings. Many factors have contributed to our knowledge of different clinical forms of PCOS in adolescent girls. They are helpful for clarifying misleading situations in a period of life when diagnosis of PCOS implies a treatment for many years and may interfere with gynecological outcome. During the last 3 years, we had the opportunity to manage in our unit 45 adolescent girls with ovarian hyperandrogenism: 32 of them had PCOS and the other 13 functional ovarian hyperandrogenism defined by clinical and biological hyperandrogenism without ultrasonographic abnormality. In this review, we report, from our personal experience as well as from recent literature data, the different clinical expressions of PCOS in the pubertal period: the classical post menarchal form, the exceptional pre menarchal form, the post precocious pubarche and the post precocious puberty forms, the familial expression as well as the dominant metabolic expression.

Molecular progress in infertility: polycystic ovary syndrome

OBJECTIVE

To review the evidence that polycystic ovary syndrome is a genetic disease.

DESIGN

Review of published literature.

RESULTS

The existing literature provides a strong basis for arguing that PCOS clusters in families. However, the mode of inheritance of the disorder is still uncertain, although the majority of studies are consistent with an autosomal dominant pattern, modified perhaps by environmental factors. In addition, studies on PCOS cells (theca, muscle, and adipocytes) in culture have documented a persistent biochemical and molecular phenotype that distinguishes them from normal cells. Although several loci have been proposed as PCOS genes including CYP11A, the insulin gene, and a region near the insulin receptor, the evidence supporting linkage is not overwhelming. The strongest case can be made for the region near the insulin receptor gene, as it has been identified in two separate studies. However, the responsible gene at chromosome 19p13.3 remains to be identified. Association studies have provided a number of potential loci with genetic variants that may create or add to a PCOS phenotype, including Calpain 10, IRS-1 and -2, and SHBG.

CONCLUSIONS

Collectively, these findings are consistent with the concept that a gene or several genes are linked to PCOS susceptibility. Because the mutations/genotypes associated with PCOS are rare, and their full impact on the phenotype incompletely understood, routine screening of women with PCOS or stigmata of PCOS for these genetic variants is not indicated at this time. Currently the treatment implications for individually identified genetic variants is uncertain and must be addressed on a case by case basis.

Comment: CAPN10 alleles are associated with polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is characterized by chronic anovulation infertility, hyperandrogenemia, and frequently insulin resistance. This study investigated whether polymorphisms in the CAPN10 gene are related with PCOS etiology. The allelic frequencies and genotypes of CAPN10 polymorphisms UCSNP-44, 43, 19, and 63 were determined in 55 well characterized women with polycystic ovaries and 93 unrelated healthy controls using spectrofluorimetric analyses and real-time PCR. Our data indicate that CAPN10 UCSNP-44 allele is associated with PCOS in the Spanish population (P = 0.01). These results support a role of Calpain 10 gene in PCOS susceptibility in humans.

Prevalence of polycystic ovary syndrome (PCOS) in first-degree relatives of patients with PCOS

OBJECTIVE

To determine the rate of clinically evident polycystic ovary syndrome (PCOS) among first-degree female relatives within families with a proband affected by PCOS.

DESIGN

Clinical and biochemical evaluation of the mothers and sisters of 93 patients with PCOS. The diagnosis of PCOS was established by: [1] a history of oligomenorrhea, [2] clinical evidence (i.e., hirsutism) or biochemical evidence (i.e., elevated total or free T) of hyperandrogenism, and [3] the exclusion of related disorders.

SETTING

Tertiary care university.

PATIENT(S)

Patients with PCOS and their mothers and sisters.

INTERVENTION(S)

Interview, physical examination, and hormonal testing on blood samples were performed for all subjects.

MAIN OUTCOME MEASURE(S)

The presence of hirsutism and hyperandrogenemia was determined in the mothers and sisters of the patients with PCOS.

RESULT(S)

Of the 78 mothers and 50 sisters evaluated clinically, 19 (24%) and 16 (32%) were affected with PCOS, respectively. A higher rate of PCOS was observed when only premenopausal women not taking hormones (i.e., untreated) were considered (i.e., 35% of mothers and 40% of sisters), consistent with amelioration of symptoms with hormonal therapy or aging. These rates of PCOS are significantly higher than that observed in our general population (approximately 4%) and suggest the involvement of a major genetic component in the disorder.

CONCLUSION(S)

The rates of PCOS in mothers and sisters of patients with PCOS were 24% and 32%, respectively, although the risk was higher when considering untreated premenopausal women only.

Polymorphisms in dopamine receptors: what do they tell us?

Many genetic studies have focussed on dopamine receptors and their relationship to neuropsychiatric disease. Schizophrenia, bipolar disorder, and substance abuse have been the most studied, but no conclusive linkage or association has been found. The possible influence of dopamine receptor variants on drug response has not received as much attention. While there is some evidence that polymorphisms and mutations in dopamine receptors can alter functional activity and pharmacological profiles, no conclusive data link these gene variants to drug response or disease. The lack of unequivocal findings may be related, in part, to the subtle changes in receptor pharmacology that these polymorphisms and mutations mediate. These subtle effects may be obscured by the influence of genes controlling drug metabolism and kinetics. Further insight into the pharmacogenetics of dopamine receptors may require not just more studies, but novel approaches to the study of complex genetic traits and diseases.

Polycystic ovary syndrome: a single gene mutation or an evolving set of symptoms

Polycystic ovary syndrome is one of the most common endocrinopathies among women. Nevertheless, there is no one single acceptable definition for this syndrome, its pathophysiology is not completely understood and its etiology remains an enigma. Several studies have examined the genetic basis of polycystic ovary syndrome with varying results, probably caused by the different criteria used to define the syndrome. These studies, together with studies that deal with reclassification of polycystic ovary syndrome, are described in the following review. Furthermore, a simplified alternative approach to this symptom complex is proposed.