Significant linkage evidence for a predisposition gene for pelvic floor disorders on chromosome 9q21

Advances in molecular mechanisms of pelvic organ prolapse (Review)

Pelvic organ prolapse (POP) is a common gynecological benign disease occurring in middle-aged and elderly females. Its incidence increases every year. To date, the majority of studies investigating its etiology have not evaluated the underlying molecular mechanisms, which has caused substantial difficulties in the prevention, treatment and prognosis of POP. In the present narrative review, recent research studies concerning the molecular mechanisms of POP were systematically reviewed and the advances were summarized. The association between the incidence of POP and the reduction of the extracellular matrix, activation of oxidative stress, genetic susceptibility, denervation of the pelvic floor and reduction of estrogen infiltration were explored. POP is mainly associated with damage of pelvic floor muscles and connective tissue, which are directly caused by pregnancy and vaginal delivery. The majority of the molecular and genetic mutations associated with POP involve specific components of connective tissue synthesis and degradation. It is likely that macroscopic parameters, such as anatomy, lifestyle and reproductive factors, interact with microscopic parameters, such as physiology and genetics in the female pelvic floor, leading to POP. Additional research studies investigating the molecular mechanisms of POP should be performed, since they may aid public health strategies. In the present narrative review, a summary of these molecular mechanisms underlying the development of POP is provided. This included the relevant proteins and genes involved. On this basis, countermeasures were proposed.

Systematic review and meta-analysis of genetic association studies of pelvic organ prolapse

INTRODUCTION AND HYPOTHESIS

Family and twin studies demonstrate that pelvic organ prolapse (POP) is heritable, but the genetic etiology is poorly understood. This review aimed to identify genetic loci and specific polymorphisms associated with POP, while assessing the strength, consistency, and risk of bias among reported associations.

METHODS

Updating an earlier systematic review, PubMed and HuGE Navigator as well as relevant conference abstracts were searched using genetic and phenotype keywords from 2015 to 2020. Screening and data extraction were performed in duplicate. Fixed and random effects meta-analyses were conducted using co-dominant models of inheritance. We assessed credibility of pooled associations using interim Venice criteria.

RESULTS

We screened 504 new abstracts and included 46 published and 7 unpublished studies. In pooled analyses we found significant associations for four polymorphisms: rs2228480 at the ESR1 gene (OR 0.67 95% CI 0.46-0.98, I² = 0.0%, Venice rating BAB), rs12589592 at the FBLN5 gene (OR 1.46 95% CI 1.11-1.82, I² = 36.3%, Venice rating BBB), rs484389 in the PGR gene (OR 0.61 95% CI 0.39-0.96, I² = 32.4%, Venice rating CBB), and rs1800012 at the COL1A1 gene (OR 0.80 95% CI 0.66-0.96, I² = 0.0%, Venice rating BAB). Further credible novel variants have also been recently identified in genome-wide association studies.

CONCLUSION

The genetic contributions to POP remain poorly understood. Several biologically plausible variants have been identified, but much work is required to establish the role of these genes in the pathogenesis of POP or to establish a role for genetic testing in clinical practice.

Polymorphism on chromosome 20p13 near the IDH3B gene is associated with uterine prolapse

OBJECTIVES

Previous studies have found evidence for a genetic basis for pelvic organ prolapse (POP), but no genetic studies have differentiated between types of POP. This study investigated whether genetic variants in six previously suggested candidate loci for POP modify the risk of uterine prolapse (UP).

STUDY DESIGN

One hundred patients, aged 30-55 years, who had undergone surgery due to total UP and 105 healthy controls were included in this study. After extracting the genomic DNA from peripheral blood, six single nucleotide polymorphisms (SNPs) previously identified for POP were genotyped, and association analysis was performed for contributing risk factors. RNA expression was determined from sacrouterine ligaments of patients and controls using quantitative reverse transcription polymerase chain reaction.

RESULTS

The dominant genotype model for the T allele for SNP rs6051098 at the chromosome 20p13 locus was significant, and this remained significant with the risk factor regression model (p=0.046; odds ratio 1.93, 95 % confidence interval 1.01-3.66). The isocitrate dehydrogenase 3 beta (IDH3B) gene was the only potential candidate gene in the 20p13 locus that was significantly upregulated in sacrouterine biopsies in women with UP compared with controls (p = 0.034).

CONCLUSION

To the best of the authors' knowledge, this is the first study to show that genetic risk factors contribute to UP, and suggested rs6051098 as the best candidate risk factor associated with UP. According to expression data in sacrouterine tissue, this study suggests that the IDH3B gene plays a role in the pathogenesis of UP.

Identification of pelvic organ prolapse risk susceptibility gene SNP locus in Xinjiang women

INTRODUCTION AND HYPOTHESIS

Susceptibility genes play an important role and have regional specificity in the occurrence of pelvic organ prolapse (POP). This study aims to identify POP susceptibility genes and their loci in ethnic minorities with different genetic backgrounds from Xinjiang in China, providing a theoretical basis for early POP diagnosis, treatment and prevention.

METHODS

Genomic DNA from peripheral blood of 196 patients was prepared; there were 88 POP patients and 108 non-pelvic floor dysfunction patients. We selected 16 different susceptibility gene single-nucleotide polymorphism (SNP) loci, which had been identified as associated with POP risk by researchers in other countries, and carried out genotyping through the Snapshot reaction. The allele and genotype frequencies, odds ratio (OR) and 95% confidence interval (CI) were analyzed using SPSS 17.0 software.

RESULTS

The genotypic and allelic distributions demonstrated significant differences between the patients and the control subjects in the group of minority women, details are as follows: ESR1 rs17847075 AG: OR = 2.738, 95% CI = 1.067-7.025, P = 0.041; ESR1 rs2234693 TC: OR = 2.99, 95% CI = 1.163-7.684, P = 0.024; ZFAT rs1036819 CC: OR = 10.286, 95% CI = 1.158-91.386, P = 0.036; allele C: OR = 2.212, 95% CI = 1.146-4.269; P = 0.02; FBLN5 rs12589592 AA: OR = 0.111, 95% CI = 0.013-0.952, P = 0.029; allele A: OR = 0.482, 95% CI = 0.254-0.913, P = 0.028.

CONCLUSIONS

ESR1 rs17847075 genotype AG in the dominant model (P = 0.008) or heterozygous model (P = 0.045), ESR1 rs2234693 genotype TC in the dominant model (P = 0.008) or heterozygous model (P = 0.028), and ZFAT rs1036819 genotype CC and allele C in the recessive model (P = 0.042) were significantly associated with POP risk in Xinjiang woman.

Identification of key genes and pathways in pelvic organ prolapse based on gene expression profiling by bioinformatics analysis

PURPOSE

The aim of this study was to elucidate the molecular mechanisms and to identify the key genes and pathways for pelvic organ prolapse (POP) using bioinformatics analysis.

METHODS

The microarray data for GSE53868 included 12 POP and 12 non-POP anterior vaginal wall samples. Differentially expressed genes (DEGs) were identified by GEO2R online tool. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed using the DAVID database, and a DEG-associated protein-protein interaction (PPI) network was constructed using STRING and visualized in Cytoscape. MCODE was used for module analysis of the PPI network.

RESULTS

A total of 257 upregulated and 333 downregulated genes were identified. GO and KEGG pathway enrichment analyses showed that the upregulated DEGs were strongly associated with immune response, complement activation, classical pathway, phagocytosis, and recognition; the downregulated genes were mainly associated with cellular response to zinc ion, negative regulation of growth, and apoptotic process. Based on the PPI network, IL6, MYC, CCL2, ICAM1, PTGS2, SERPINE1, ATF3, CDKN1A, and CDKN2A were screened as hub genes. The four most significant sub-modules of DEGs were extracted after network module analysis. These genes were mainly associated with the negative regulation of growth and inflammatory response. The KEGG pathway enrichment analysis revealed that these genes were associated with Mineral absorption, Jak-STAT signaling pathway, cytokine-cytokine receptor interaction, and chemokine signaling pathway.

CONCLUSIONS

These microarray data and bioinformatics analyses provide a useful method for the identification of key genes and pathways associated with POP. Moreover, some crucial DEGs, such as IL6, MYC, CCL2, ICAM1, PTGS2, SERPINE1, ATF3, CDKN1A, and CDKN2A, potentially play an important role in the development and progression of POP.

Clinical epidemiological insights into urinary incontinence

INTRODUCTION AND HYPOTHESIS

Urinary incontinence (UI) is very common and heterogeneous among women with limited knowledge of progression or prognosis. Evidence based on clinical epidemiology can help to better understand the natural history of UI.

METHODS

We examine the challenges of UI definition and its subtypes, its impact on quality of life and health-seeking behavior. We review the proposed pathophysiology of UI subtypes and known risk factors as they relate to our current knowledge of the disease state. Finally, we emphasize the role of epidemiology in the process of acquiring new insight, improving knowledge, and translating this information into clinical practice.

RESULTS

Stress UI is most common overall, but mixed UI is most prevalent in older women. The three UI subtypes have some common risk factors, and others that are unique, but there remains a significant gap in our understanding of how they develop. Although the pathophysiology of stress UI is somewhat understood, urgency UI remains mostly idiopathic, whereas mixed UI is the least studied and most complex subtype. Moreover, there exists limited information on the progression of symptoms over time, and disproportionate UI health-seeking behavior. We identify areas of exploration (e.g., epigenetics, urinary microbiome), and offer new insights into a better understanding of the relationship among the UI subtypes and to develop an integrated construct of UI natural history.

CONCLUSION

Future epidemiological strategies using longitudinal study designs could play a pivotal role in better elucidating the controversies in UI natural history and the pathophysiology of its subtypes leading to improved clinical care.

Predicting urinary incontinence in women in later life: A systematic review

Urinary incontinence (UI) affects 10-40% of the population and treatment costs in the UK are estimated to be £233 million per annum. A systematic review of online medical databases between July 1974 and 2016 was conducted to identify studies that had investigated risk and prediction strategies of UI in later life. Eighteen prospective longitudinal studies fulfilled the search criteria. These were analysed systematically (as per the PRISMA checklist) and bias risk through study design was minimised where possible upon data analysis. One paper proposed a predictive assessment tool called the 'continence index'. It was derived following secondary analysis of a cohort study and its predictive threshold had suboptimal sensitivity (79%) and specificity (65%) rates. Seventeen studies identified multiple strong risk factors for UI but despite a large selection of papers on the topic, no robust risk assessment tool prospectively identified patients at risk of UI in later life. Thus more research in this field is required. Clinicians should be aware particularly of modifiable UI risk factors to help reduce the clinical burden of UI in the long term.

Genetic Mutation that May Contribute to Failure of Prolapse Surgery in White Women: A Case-Control Study

OBJECTIVE

To identify a potential genetic basis for early failure after prolapse surgery.

DESIGN

Case-control study (Canadian Task Force classification II).

SETTING

This study was carried out in 1 academic community medical center referral practice, and all patients had surgery at 1 of 2 hospitals.

PATIENTS

Ten women with early, multicompartment prolapse recurrence after robotic sacrocolpopexy compared with 40 control subjects with known success after the same procedure.

INTERVENTIONS

Patients were treated with robotic sacrocolpopexy.

MEASUREMENTS AND MAIN RESULTS

DNA was isolated and initially genotyped on a single nucleotide polymorphism (SNP) array to direct more detailed exome analyses. Exome sequences were mapped to the Human Genome Reference Sequence (GRCh37), and variants were compared between groups and to participants in the 1000 Genomes Project. Statistical analyses were performed using a software package commonly used in genetics research. TaqMan assay was used for verification, and p values were adjusted using the false discovery rate. Demographics of groups were compared using χ(2), Mann-Whitney U, and t tests. A SNP [rs171821] located near the ZFYVE16 gene was associated with patients but not control subjects, and the false discovery rate-adjusted p value was .046 (odds ratio, 45.2; 95% confidence interval, 5.06-403). Exome analyses of this gene yielded another SNP [rs249038 (G/A)] in 6 of 10 patients and none of the control subjects (p = .02). This SNP causes a heterozygous missense mutation of glycine to serine predicted to be deleterious by the Protein Variation Effect Analyzer and was also very rare among participants in the 1000 Genomes Project (p < .001).

CONCLUSIONS

Two SNPs located near the ZFYVE16 gene on chromosome 5 may have played a role in the early, multicompartment sacrocolpopexy failure experienced by our patients. (www.clinicaltrials.gov Identifier: NCT01614587).

Verification of the Chromosome Region 9q21 Association with Pelvic Organ Prolapse Using RegulomeDB Annotations

Pelvic organ prolapse (POP) is a common highly disabling disorder with a large hereditary component. It is characterized by a loss of pelvic floor support that leads to the herniation of the uterus in or outside the vagina. Genome-wide linkage studies have shown an evidence of POP association with the region 9q21 and six other loci in European pedigrees. The aim of our study was to test the above associations in a case-control study in Russian population. Twelve SNPs including SNPs cited in the above studies and those selected using the RegulomeDB annotations for the region 9q21 were genotyped in 210 patients with POP (stages III-IV) and 292 controls with no even minimal POP. Genotyping was performed using the polymerase chain reaction with confronting two-pair primers (PCR–CTPP). Association analyses were conducted for individual SNPs, 9q21 haplotypes, and SNP-SNP interactions. SNP rs12237222 with the highest RegulomeDB score 1a appeared to be the key SNP in haplotypes associated with POP. Other RegulomeDB Category 1 SNPs, rs12551710 and rs2236479 (scores 1d and 1f, resp.), exhibited epistatic effects. In this study, we verified the region 9q21 association with POP in Russians, using RegulomeDB annotations.

Evidence for pelvic organ prolapse predisposition genes on chromosomes 10 and 17

OBJECTIVE

We conducted a genomewide linkage analysis to identify pelvic organ prolapse (POP) predisposition genes using a resource of high-risk POP pedigrees.

STUDY DESIGN

Cases are defined as women who reported bothersome symptoms of POP based on standardized symptom questions (Pelvic Floor Distress Inventory, moderately or quite bothered), and/or received treatment for POP documented in medical records. Our complete pedigree resource contains 299 familial POP cases in 83 high-risk pedigrees. Genotype data were obtained from Illumina HumanHap550, 610Q, the Human1M-Duo, Human Omni1-Quad, or the Human Omni 2.5 platforms. A set of single nucleotide polymorphism markers common to all platforms was identified and markers in high linkage disequilibrium were removed. We performed a genomewide linkage analysis under general dominant and recessive models using a Markov chain, Monte Carlo linkage analysis method implemented in MCLINK (University of Utah) software. Because 70 individuals in 32 pedigrees were used in a previously published linkage analysis for a phenotype of POP requiring treatment/surgery, we also performed linkage only including the 225 newly recruited and genotyped cases in 61 pedigrees.

RESULTS

Linkage analysis using our complete pedigree resource for the loosened criteria of bothersome POP showed evidence for significant genomewide linkage on chromosome 10q24-26 (recessive model, maximum heterogeneity logarithm of odds 3.4); suggestive evidence was identified on chromosomes 6 and 17, and an additional region on chromosome 10. In the subset of only the newly recruited familial POP cases, significant evidence for genomewide linkage was observed on chromosome 17q25 (recessive model, maximum heterogeneity logarithm of odds 3.3), and suggestive evidence for linkage was observed on chromosomes 10 and 11. Neither analysis duplicated the previously published linkage evidence for the POP requiring treatment/surgery phenotype observed on chromosome 9.

CONCLUSION

While the etiology of this common condition is unknown, this study provides evidence that loci on chromosomes 10q and 17q may contribute to POP etiology.

Novel interstitial 2.6 Mb deletion on 9q21 associated with multiple congenital anomalies

Array comparative genomic hybridization (aCGH) is now commonly used to identify copy number changes in individuals with developmental delay, intellectual disabilities, autism spectrum disorders, and/or multiple congenital anomalies. We report on an infant with multiple congenital anomalies and a novel 2.6 Mb interstitial deletion within 9q21.32q21.33 detected by aCGH. Her clinical presentation included dysmorphic craniofacial features, cleft palate, atrial septal defect, bicornuate uterus, bilateral hip dislocation, hypotonia, and recurrent pneumonia. Parental aCGH studies were negative for copy loss in this region. To our knowledge, no similar deletions have been reported in available databases or published literature. This deletion encompasses 12 genes, and prediction algorithms as well as experimental data suggest that a subset is likely to be haploinsufficient. Included are a neurotrophin receptor (NKG2D), a gene implicated in cilia function (KIF27), an adaptor protein important for ubiquitin-dependent protein quality control (UBQLN1), a gene important for transcription and signaling (HNRNPK), and a gene involved in maintaining genomic stability (RMI1). Identifying additional patients with similar copy losses and further study of these genes will contribute to a better understanding of the pathophysiology of multiple congenital anomalies.

Genetic epidemiology of pelvic organ prolapse: a systematic review

Given current evidence supporting a genetic predisposition for pelvic organ prolapse, we conducted a systematic review of published literature on the genetic epidemiology of pelvic organ prolapse. Inclusion criteria were linkage studies, candidate gene association and genome-wide association studies in adult women published in English and indexed in PubMed through Dec. 2012, with no limit on date of publication. Methodology adhered to the PRISMA guidelines. Data were systematically extracted by 2 reviewers and graded by the Venice criteria for studies of genetic associations. A metaanalysis was performed on all single nucleotide polymorphisms evaluated by 2 or more studies with similar methodology. The metaanalysis suggests that collagen type 3 alpha 1 (COL3A1) rs1800255 genotype AA is associated with pelvic organ prolapse (odds ratio, 4.79; 95% confidence interval, 1.91-11.98; P = .001) compared with the reference genotype GG in populations of Asian and Dutch women. There was little evidence of heterogeneity for rs1800255 (P value for heterogeneity = .94; proportion of variance because of heterogeneity, I(2) = 0.00%). There was insufficient evidence to determine whether other single nucleotide polymorphisms evaluated by 2 or more papers were associated with pelvic organ prolapse. An association with pelvic organ prolapse was seen in individual studies for estrogen receptor alpha (ER-α) rs2228480 GA, COL3A1 exon 31, chromosome 9q21 (heterogeneity logarithm of the odds score 3.41) as well as 6 single nucleotide polymorphisms identified by a genome-wide association study. Overall, individual studies were of small sample size and often of poor quality. Future studies would benefit from more rigorous study design as outlined in the Venice recommendations.

Fibulin-5 (FBLN5) gene polymorphism is associated with pelvic organ prolapse

OBJECTIVE

FBLN5 encodes a key protein of elastic fiber matrix assembly and function that contributes to maintaining pelvic support and plays the important role in the pathophysiology of pelvic organ prolapse (POP). The aim of the study was to investigate whether there is an association between common single-nucleotide polymorphisms (SNPs) of the FBLN5 gene and POP.

STUDY DESIGN

A total of eleven tag SNPs of the FBLN5 gene were genotyped using the polymerase chain reaction with confronting two-pair primers (PCR-CTPP) in 210 patients with POP (stages III-IV) and 292 controls with no even minimal POP.

RESULTS

We revealed significant associations of tag SNPs rs2018736 and rs12589592 with POP. The top association signal was found for SNP rs2018736 (protective effect for the minor allele A) in the entire set: p=0.0026, OR=0.42, 95% CI: 0.24-0.75; in the stratum with pelvic floor trauma: p=0.0018, OR=0.27, 95% CI: 0.11-0.64; and in the stratum with fetal macrosomia: p=0.013, OR=0.14, 95% CI: 0.03-0.71. The results of the haplotype analyses were consistent with the single SNP analysis. In the strata without perineal trauma and fetal macrosomia effects were non-significant, possibly, due to the smaller effect sizes.

CONCLUSIONS

Current data provide, for the first time, strong evidence that common SNPs of the FBLN5 gene are associated with POP especially after pelvic floor injury.

Significant evidence of linkage for a gene predisposing to colorectal cancer and multiple primary cancers on 22q11

Objectives:

The genetic basis of colorectal cancer (CRC) is not completely specified. Part of the difficulty in mapping predisposition genes for CRC may be because of phenotypic heterogeneity. Using data from a population genealogy of Utah record linked to a statewide cancer registry, we identified a subset of CRC cases that exhibited familial clustering in excess of that expected for all CRC cases in general, which may represent a genetically homogeneous subset of CRC.

Methods:

Using a new familial aggregation method referred to as the subset genealogic index of familiality (subsetGIF), combined with detailed information from a statewide tumor registry, we identified a subset of CRC cases that exhibited excess familial clustering above that expected for CRC: CRC cases who had at least one other primary tumor at a different site. A genome-wide linkage analysis was performed on a set of high-risk CRC pedigrees that included multiple CRC cases with additional primaries to identify evidence for predisposition loci.

Results:

A total of 13 high-risk CRC pedigrees with multiple CRC cases with other primary cancers were identified. Linkage analysis identified one pedigree with a significant linkage signal at 22q11 (LOD (logarithm (base 10) of odds)=3.39).

Conclusions:

A predisposition gene or variant for CRC that also predisposes to other primary cancers likely resides on chromosome 22q11. The ability to use statewide population genealogy and tumor registry data was critical to identify an informative subset of CRC cases that is possibly more genetically homogeneous than CRC in general, and may have improved statistical power for predisposition locus identification in this study.

Female urinary incontinence during pregnancy and after delivery: Clinical impact and contributing factors

Urinary incontinence (UI) is a common condition affecting adult women of all ages and it could have a negative influence on quality of life. The etiology of UI is multifactorial, but some of the most important risk factors are obesity and ageing, as well as adverse obstetric events. Pregnancy and delivery per se have been implicated in the etiology of UI. Although several studies have demonstrated a direct association between UI and vaginal delivery in short, medium and long-term, the role of childbirth on the risk of UI remains controversial. The mechanical strain during delivery may induce injuries to the muscle, connective and neural structures. Vaginal birth can be associated with relaxation or disruption of fascial and ligamentous supports of pelvic organs. Parity, instrumental delivery, prolonged labor and increased birth weights have always been considered risk factors for pelvic floor injury. Also genetic factors have been recently raised up but still there are not appropriate guidelines or measures to reduce significantly the incidence of UI. The role of pelvic floor muscle training (PFMT) in the prevention and treatment of UI is still unclear. However, PFMT seems to be useful when supervised training is conducted and it could be incorporated as a routine part of women’s exercise programmes during pregnancy and after childbirth.

Recent status of the treatment of stress urinary incontinence

The therapeutic options for management of stress urinary incontinence can be conservative, pharmacological or surgical. The treatment of patients with stress urinary incontinence should be tailored to the individual to optimize care. A multitude of surgical techniques have emerged to treat this condition in recent years. The objective of the present review was to present an overview of current practice in the management of stress urinary incontinence while considering the evidence supporting the clinical effectiveness of these procedures.

Phenotyping clinical disorders: lessons learned from pelvic organ prolapse

Genetic epidemiology, the study of genetic contributions to risk for disease, is an innovative area in medicine. Although research in this arena has advanced in other disciplines, few genetic epidemiological studies have been conducted in obstetrics and gynecology. It is crucial that we study the genetic susceptibility for issues in women's health because this information will shape the new frontier of personalized medicine. To date, preterm birth may be one of the best examples of genetic susceptibility in obstetrics and gynecology, but many areas are being evaluated including endometriosis, fibroids, polycystic ovarian syndrome, and pelvic floor disorders. An essential component to genetic epidemiological studies is to characterize, or phenotype, the disorder to identify genetic effects. Given the growing importance of genomics and genetic epidemiology, we discuss the importance of accurate phenotyping of clinical disorders and highlight critical considerations and opportunities in phenotyping, using pelvic organ prolapse as a clinical example.

Identification of six loci associated with pelvic organ prolapse using genome-wide association analysis

OBJECTIVE

There is evidence that both environmental and genetic factors contribute to pelvic organ prolapse. We conducted a genome-wide association study to investigate whether common genetic variants modify the risk of pelvic organ prolapse.

METHODS

We recruited women who had been evaluated and treated for pelvic organ prolapse at the University of Utah from 1996 to 2008 and their affected female relatives. Those in the case group were genotyped on the Illumina 550K platform. We genetically matched 2,976 white control participants available from Illumina as the control group. Association tests were adjusted for related participants using two different software programs: EMMAX and Genie. Confirmation of findings was performed in a cohort of Dutch women (n=76) with recurrent pelvic organ prolapse and family history of pelvic organ prolapse.

RESULTS

The Utah study sample included 115 case group participants treated for pelvic organ prolapse, in most case group participants with surgery (n=78) or repeat surgery (n=35). Results from association analyses using EMMAX software identified five single-nucleotide polymorphisms (SNPs) significantly associated with pelvic organ prolapse (P<1×10). Independent association analysis with Genie software identified three of the same SNPs and one additional SNP. The six SNPs were located at 4q21 (rs1455311), 8q24 (rs1036819), 9q22 (rs430794), 15q11 (rs8027714), 20p13 (rs1810636), and 21q22 (rs2236479). Nominally significant findings (P<.05) or findings trending toward significance (P<.1) were observed for five of the six SNPs in the Dutch cohort.

CONCLUSION

Six SNPs have been identified that are significantly associated with pelvic organ prolapse in high-risk familial case group participants and that provide evidence for a genetic contribution to pelvic organ prolapse.

LEVEL OF EVIDENCE

II.

Characterizing the phenotype of advanced pelvic organ prolapse

OBJECTIVE

Genetic studies require a clearly defined phenotype to reach valid conclusions. Our aim was to characterize the phenotype of advanced prolapse by comparing women with stage III to IV prolapse with controls without prolapse.

METHODS

Based on the pelvic organ prolapse quantification examination, women with stage 0 to stage I prolapse (controls) and those with stage III to stage IV prolapse (cases) were prospectively recruited as part of a genetic epidemiologic study. Data regarding sociodemographics; medical, obstetric, and surgical history; family history; and body mass index were obtained by a questionnaire administered by a trained coordinator and abstracted from electronic medical records.

RESULTS

There were 275 case patients with advanced prolapse and 206 controls with stage 0 to stage I prolapse. Based on our recruitment strategy, the women were younger than the controls (64.7 ± 10.1 vs 68.6 ± 10.4 years; P<0.001); cases were also more likely to have had one or more vaginal deliveries (96.0% vs 82.0%; P<0.001). There were no differences in race, body mass index, and constipation. Regarding family history, cases were more likely to report that either their mother and/or sister(s) had prolapse (44.8% vs 16.9%, P<0.001). In a logistic regression model, vaginal parity (odds ratio, 4.05; 95% confidence interval, 1.67-9.85) and family history of prolapse (odds ratio, 3.74; 95% confidence interval, 2.16-6.46) remained significantly associated with advanced prolapse.

CONCLUSIONS

Vaginal parity and a family history of prolapse are more common in women with advanced prolapse compared to those without prolapse. These characteristics are important in phenotyping advanced prolapse, suggesting that these data should be collected in future genetic epidemiologic studies.

Comprehensive analysis of LAMC1 genetic variants in advanced pelvic organ prolapse

OBJECTIVE

We sought to comprehensively evaluate the association of laminin gamma-1 (LAMC1) and advance pelvic organ prolapse.

STUDY DESIGN

We conducted a candidate gene association of patients (n = 239) with stages III-IV prolapse and controls (n = 197) with stages 0-I prolapse. We used a linkage disequilibrium (LD)-tagged approach to identify single-nucleotide polymorphisms (SNPs) in LAMC1 and focused on non-Hispanic white women to minimize population stratification. Additive and dominant multivariable logistic regression models were used to test for association between individual SNPs and advanced prolapse.

RESULTS

Fourteen SNPs representing 99% coverage of LAMC1 were genotyped. There was no association between SNP rs10911193 and advanced prolapse (P = .34). However, there was a trend toward significance for SNPs rs1413390 (P = .11), rs20563 (P = .11), and rs20558 (P = .12).

CONCLUSION

Although we found that the previously reported LAMC1 SNP rs10911193 was not associated with nonfamilial prolapse, our results support further investigation of this candidate gene in the pathophysiology of prolapse.

Chromosome 2p14 is linked to susceptibility to leprosy

BACKGROUND

A genetic component to the etiology of leprosy is well recognized but the mechanism of inheritance and the genes involved are yet to be fully established.

METHODOLOGY

A genome-wide single nucleotide polymorphism (SNP) based linkage analysis was carried out using 23 pedigrees, each with 3 to 7 family members affected by leprosy. Multipoint parametric and non-parametric linkage analyses were performed using MERLIN 1.1.1.

PRINCIPAL FINDINGS

Genome-wide significant evidence for linkage was identified on chromosome 2p14 with a heterogeneity logarithm of odds (HLOD) score of 3.51 (rs1106577) under a recessive model of inheritance, while suggestive evidence was identified on chr.4q22 (HLOD 2.92, rs1349350, dominant model), chr. 8q24 (HLOD 2.74, rs1618523, recessive model) and chr.16q24 (HLOD 1.93, rs276990 dominant model). Our study also provided moderate evidence for a linkage locus on chromosome 6q24-26 by non-parametric linkage analysis (rs6570858, LOD 1.54, p = 0.004), overlapping a previously reported linkage region on chromosome 6q25-26.

CONCLUSION

A genome-wide linkage analysis has identified a new linkage locus on chromosome 2p14 for leprosy in Pedigrees from China.

Pelvic floor disorders: linking genetic risk factors to biochemical changes

Pelvic floor disorders (PFDs) such as stress urinary incontinence (SUI) and pelvic organ prolapse (POP) may share a common pathophysiological process related to pelvic floor tissue laxity and loss of support. We reviewed recent literature on observed biochemical changes in women with SUI and POP, linking them to genetic predisposition. We found that studies of pelvic tissues showed differences between control subjects and women with POP and SUI in collagen and elastin structure at a molecular and fibrillar level. Studies were heterogeneous but showed a trend towards decreased collagen and elastin content. The contribution of matrix metalloproteinases to increased collagenolysis can be related to genetic polymorphisms present in higher frequency in women with PFD. Extracellular matrix (ECM) protein turnover plays a role in the development of POP and SUI, but much remains to be understood of this complex dynamic interplay of enzymes, proteins and molecules. Genotyping of candidate genes participating in ECM formation will elucidate the missing link between the manifestation of the disease and the biochemical changes observed systematically, in addition to those in the pelvic floor.

Genetics of pelvic organ prolapse: crossing the bridge between bench and bedside in urogynecologic research

An increasing number of scientists have studied the molecular and biochemical basis of pelvic organ prolapse (POP). The extracellular matrix content of the pelvic floor is the major focus of those investigations and pointed for potential molecular markers of the dysfunction. The identification of women predisposed to develop POP would help in the patients' management and care. This article includes a critical analysis of the literature up to now; discusses implications for future research and the role of the genetics in POP.

Surgical management of stress urinary incontinence in women: safety, effectiveness and cost-utility of trans-obturator tape (TOT) versus tension-free vaginal tape (TVT) five years after a randomized surgical trial

BACKGROUND

We recently completed a randomized clinical trial of two minimally invasive surgical procedures for stress urinary incontinence, the retropubic tension-free vaginal tape (TVT) versus the trans-obturator tape (TOT) procedure. At one year postoperatively, we were concerned to find that a significant number of women had tape that was palpable when a vaginal examination was undertaken. Because the risk factors for adverse outcomes of tape surgery are not clearly understood, we are unable to say whether palpable tapes will lead to vaginal erosions or whether they merge into vaginal tissue. We do not know whether patients go on to have further adverse consequences of surgery, leading to additional cost to patients and healthcare system. Our current study is a 5 year follow-up of the women who took part in our original trial.

METHODS/DESIGN

All 199 women who participated in our original trial will be contacted and invited to take part in the follow-up study. Consenting women will attend a clinic visit where they will have a physical examination to identify vaginal erosion or other serious adverse outcomes of surgery, undertake a standardized pad test for urinary incontinence, and complete several health-related quality of life questionnaires (15D, UDI-6, IIQ-7). Analyses will compare the outcomes for women in the TOT versus TVT groups. The cost-effectiveness of TOT versus TVT over the 5 years after surgery, will be assessed with the use of disease-specific health service administrative data and an objective health outcome measure. A cost-utility analysis may also be undertaken, based on economic modeling, data from the clinical trial and inputs obtained from published literature.

DISCUSSION

This study is needed now, because TOT and TVT are among the most frequently conducted surgical procedures for stress urinary incontinence in Canada. Because stress urinary incontinence is so common, the impact of selecting an approach that causes more adverse events, or is less effective, will have a significant impact on individual quality of life, and societal and health care costs.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00234754. Registered October 2005.

High quality and quantity Genome-wide germline genotypes from FFPE normal tissue

Background

Although collections of formalin fixed paraffin embedded (FFPE) samples exist, sometimes representing decades of stored samples, they have not typically been utilized to their full potential. Normal tissue from such samples would be extremely valuable for generation of genotype data for individuals who cannot otherwise provide a DNA sample.

Findings

We extracted DNA from normal tissue identified in FFPE tissue blocks from prostate surgery and obtained complete genome wide genotype data for over 500,000 SNP markers for these samples, and for DNA extracted from whole blood for 2 of the cases, for comparison.

Four of the five FFPE samples of varying age and amount of tissue had identifiable normal tissue. We obtained good quality genotype data for between 89 and 99% of all SNP markers for the 4 samples from FFPE. Concordance rates of over 99% were observed for the 2 samples with DNA from both FFPE and from whole blood.

Conclusions

DNA extracted from normal FFPE tissue provides excellent quality and quantity genome-wide genotyping data representing germline DNA, sufficient for both linkage and association analyses. This allows genetic analysis of informative individuals who are no longer available for sampling in genetic studies.

A unified theory of autism revisited: linkage evidence points to chromosome X using a high-risk subset of AGRE families

Zhao et al. [2007] in their "Unified Theory of Autism" hypothesized that incidence of autism in males could be explained by essentially two types of family structures: majority of autism cases are from low-risk autism families with de novo mutations, and a minority of cases are from high-risk multiplex families, where risk to male offspring approximates 50% consistent with a dominant model and high penetrance. Using the Autism Genetic Resource Exchange (AGRE) data set, Zhao et al. identified 86 high-risk families with likely dominant transmission. As genotype data are now available for many members of the AGRE resource, the objective of this manuscript was to determine if dominant linkage evidence for an autism predisposition gene exists in these 86 high-risk families. HumanHap550K Illumina SNP data were available for 92% of 455 total family members in these 86 high-risk families. We performed a linkage analysis using a pruned subset of markers where markers in high linkage disequilibrium were removed. We observed a single suggestive peak (maximum LOD 2.01, maximum HLOD 2.08) under a dominant model on chromosome Xp22.11-p21.2 that encompasses the IL1RAPL1 gene. Mutations or deletions in IL1RAPL1 have been previously reported in three families with autism. In our study, 11 families contributed nominally (P<0.05, HLOD>0.588) to the chromosome X peak. These results demonstrate that identification of a more homogeneous subset of autism cases, which was based on family structure in this study, may help to identify, localize and further our understanding of autism predisposition genes.

Is laminin gamma-1 a candidate gene for advanced pelvic organ prolapse?

OBJECTIVE

We sought to determine allele frequencies of 3 LAMC1 single nucleotide polymorphisms (SNPs) in Caucasian and African American (AA) women with stage>II pelvic organ prolapse (POP) (cases) and in ethnicity-matched controls with stage<II POP. We also sought to determine if LAMC1 is associated with POP within ethnic groups.

STUDY DESIGN

Allelic discrimination was performed for LAMC1 SNPs rs10911193 (C/T), rs20563 (A/G), and rs20558 (T/C). SNP and haplotype-specific tests were used to examine associations among POP, ethnicity, and LAMC1.

RESULTS

In all, 411 women were enrolled. Significant differences in allele and haplotype frequencies existed among AAs and Caucasians: rs10911193 "T" (P=.0014); rs20563 "G" (P<.0001); rs20558 "C" (P<.0001); rs20563, rs20558 "GC" (P<.0001); and rs20563, rs20558 "AT" (P<.0001). No significant associations between POP and LAMC1 SNPs or haplotypes were found within ethnicities.

CONCLUSION

While significant differences were identified between AA and Caucasian women, no associations were found between any LAMC1 gene variant and advanced POP.

Genome-wide linkage analyses of two repetitive behavior phenotypes in Utah pedigrees with autism spectrum disorders

BACKGROUND

It has been suggested that efforts to identify genetic risk markers of autism spectrum disorder (ASD) would benefit from the analysis of more narrowly defined ASD phenotypes. Previous research indicates that 'insistence on sameness' (IS) and 'repetitive sensory-motor actions' (RSMA) are two factors within the ASD 'repetitive and stereotyped behavior' domain. The primary aim of this study was to identify genetic risk markers of both factors to allow comparison of those markers with one another and with markers found in the same set of pedigrees using ASD diagnosis as the phenotype. Thus, we empirically addresses the possibilities that more narrowly defined phenotypes improve linkage analysis signals and that different narrowly defined phenotypes are associated with different loci. Secondary aims were to examine the correlates of IS and RSMA and to assess the heritability of both scales.

METHODS

A genome-wide linkage analysis was conducted with a sample of 70 multiplex ASD pedigrees using IS and RSMA as phenotypes. Genotyping services were provided by the Center for Inherited Disease Research using the 6 K single nucleotide polymorphism linkage panel. Analysis was done using the multipoint linkage software program MCLINK, a Markov chain Monte Carlo (MCMC) method that allows for multilocus linkage analysis on large extended pedigrees.

RESULTS

Genome-wide significance was observed for IS at 2q37.1-q37.3 (dominant model heterogeneity lod score (hlod) 3.42) and for RSMA at 15q13.1-q14 (recessive model hlod 3.93). We found some linkage signals that overlapped and others that were not observed in our previous linkage analysis of the ASD phenotype in the same pedigrees, and regions varied in the range of phenotypes with which they were linked. A new finding with respect to IS was that it is positively associated with IQ if the IS-RSMA correlation is statistically controlled.

CONCLUSIONS

The finding that IS and RSMA are linked to different regions that only partially overlap regions previously identified with ASD as the phenotype supports the value of including multiple, narrowly defined phenotypes in ASD genetic research. Further, we replicated previous reports indicating that RSMA is more strongly associated than IS with measures of ASD severity.