Role of HOXA7 to HOXA13 and PBX1 genes in various forms of MRKH syndrome (congenital absence of uterus and vagina)

Genetics of Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome: advancements and implications

Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome is a congenital anomaly characterized by agenesis/aplasia of the uterus and upper part of the vagina in females with normal external genitalia and a normal female karyotype (46,XX). Patients typically present during adolescence with complaints of primary amenorrhea where the diagnosis is established with significant implications including absolute infertility. Most often cases appear isolated with no family history of MRKH syndrome or related anomalies. However, cumulative reports of familial recurrence suggest genetic factors to be involved. Early candidate gene studies had limited success in their search for genetic causes of MRKH syndrome. More recently, genomic investigations using chromosomal microarray and genome-wide sequencing have been successful in detecting promising genetic variants associated with MRKH syndrome, including 17q12 (LHX1, HNF1B) and 16p11.2 (TBX6) deletions and sequence variations in GREB1L and PAX8, pointing towards a heterogeneous etiology with various genes involved. With uterus transplantation as an emerging fertility treatment in MRKH syndrome and increasing evidence for genetic etiologies, the need for genetic counseling concerning the recurrence risk in offspring will likely increase. This review presents the advancements in MRKH syndrome genetics from early familial occurrences and candidate gene searches to current genomic studies. Moreover, the review provides suggestions for future genetic investigations and discusses potential implications for clinical practice.

Molecular Basis of Müllerian Agenesis Causing Congenital Uterine Factor Infertility-A Systematic Review

Infertility affects around 1 in 5 couples in the world. Congenital absence of the uterus results in absolute infertility in females. Müllerian agenesis is the nondevelopment of the uterus. Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome is a condition of uterovaginal agenesis in the presence of normal ovaries and the 46 XX Karyotype. With advancements in reproductive techniques, women with MA having biological offspring is possible. The exact etiology of MA is unknown, although several genes and mechanisms affect the development of Müllerian ducts. Through this systematic review of the available literature, we searched for the genetic basis of MA. The aims included identification of the genes, chromosomal locations, changes responsible for MA, and fertility options, in order to offer proper management and counseling to these women with MA. A total of 85 studies were identified through searches. Most of the studies identified multiple genes at various locations, although the commonest involved chromosomes 1, 17, and 22. There is also conflicting evidence of the involvement of various candidate genes in the studies. The etiology of MA seems to be multifactorial and complex, involving multiple genes and mechanisms including various mutations and mosaicism.

The TALE never ends: A comprehensive overview of the role of PBX1, a TALE transcription factor, in human developmental defects

PBX1 is a highly conserved atypical homeodomain transcription factor (TF) belonging to the TALE (three amino acid loop extension) family. Dimerized with other TALE proteins, it can interact with numerous partners and reach dozens of regulating sequences, suggesting its role as a pioneer factor. PBX1 is expressed throughout the embryonic stages (as early as the blastula stage) in vertebrates. In human, PBX1 germline variations are linked to syndromic renal anomalies (CAKUTHED). In this review, we summarized available data on PBX1 functions, PBX1-deficient animal models, and PBX1 germline variations in humans. Two types of genetic alterations were identified in PBX1 gene. PBX1 missense variations generate a severe phenotype including lung hypoplasia, cardiac malformations, and sexual development defects (DSDs). Conversely, truncating variants generate milder phenotypes (mainly cryptorchidism and deafness). We suggest that defects in PBX1 interactions with various partners, including proteins from the HOX (HOXA7, HOXA10, etc.), WNT (WNT9B, WNT3), and Polycomb (BMI1, EED) families are responsible for abnormal proliferation and differentiation of the embryonic mesenchyme. These alterations could explain most of the defects observed in humans. However, some phenotype variability (especially DSDs) remains poorly understood. Further studies are needed to explore the TALE family in greater depth.

Identification of Genetic Causes in Mayer-Rokitansky-Küster-Hauser (MRKH) Syndrome: A Systematic Review of the Literature

Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome is a congenital condition characterizing females with absence of the uterus and part of the vagina. Several genetic defects have been correlated with the presence of MRKH; however, the exact etiology is still unknown due to the complexity of the genetic pathways implicated during the embryogenetic development of the Müllerian ducts. A systematic review (SR) of the literature was conducted to investigate the genetic causes associated with MRKH syndrome and Congenital Uterine Anomalies (CUAs). This study aimed to identify the most affected chromosomal areas and genes along with their associated clinical features in order to aid clinicians in distinguishing and identifying the possible genetic cause in each patient offering better genetic counseling. We identified 76 studies describing multiple genetic defects potentially contributing to the pathogenetic mechanism of MRKH syndrome. The most reported chromosomal regions and the possible genes implicated were: 1q21.1 (RBM8A gene), 1p31-1p35 (WNT4 gene), 7p15.3 (HOXA gene), 16p11 (TBX6 gene), 17q12 (LHX1 and HNF1B genes), 22q11.21, and Xp22. Although the etiology of MRKH syndrome is complex, associated clinical features can aid in the identification of a specific genetic defect.

Studying Müllerian duct anomalies - from cataloguing phenotypes to discovering causation

Müllerian duct anomalies (MDAs) are developmental disorders of the Müllerian duct, the embryonic anlage of most of the female reproductive tract. The prevalence of MDAs is 6.7% in the general female population and 16.7% in women who exhibit recurrent miscarriages. Individuals affected by these anomalies suffer from high rates of infertility, first-trimester pregnancy losses, premature labour, placental retention, foetal growth retardation and foetal malpresentations. The aetiology of MDAs is complex and heterogeneous, displaying a range of clinical pictures that generally lack a direct genotype-phenotype correlation. De novo and familial cases sharing the same genomic lesions have been reported. The familial cases follow an autosomal-dominant inheritance, with reduced penetrance and variable expressivity. Furthermore, few genetic factors and molecular pathways underpinning Müllerian development and dysregulations causing MDAs have been identified. The current knowledge in this field predominantly derives from loss-of-function experiments in mouse and chicken models, as well as from human genetic association studies using traditional approaches, such as microarrays and Sanger sequencing, limiting the discovery of causal factors to few genetic entities from the coding genome. In this Review, we summarise the current state of the field, discuss limitations in the number of studies and patient samples that have stalled progress, and review how the development of new technologies provides a unique opportunity to overcome these limitations. Furthermore, we discuss how these new technologies can improve functional validation of potential causative alterations in MDAs.

Summary: Here, we review the current knowledge about Müllerian duct anomalies in the context of new high-throughput technologies and model systems and their implications in the prevention of these disorders.

GREB1L as a candidate gene of Mayer-Rokitansky-Küster-Hauser Syndrome

Mayer-Rokitansky-Küster-Hauser (MRKH) Syndrome is a sex development disorder that affects 1 in every 4500 46, XX live births. At least a subset of MRKH syndrome is genetically related to which various candidate genes have been identified. The growth regulation by estrogen in breast cancer 1-like gene (GREB1L) is an androgen-regulated gene reported to be a co-activator of the retinoic acid receptor gene (RAR). Thus expression levels of GREB1L have implications on renal system cellular differentiation, morphogenesis, and homeostasis in vertebrates. Variants of GREB1L have been reported in familial and sporadic MRKH Syndrome and more importantly, in a three-generation family ofMRKH syndrome propositae. Much the same way, Mutants of GREB1L have also been identified in isolated bilateral renal agenesis and deafness both of which are extra-genital tract anomalies in MRKH type 2. Again, renal agenesis transgenic mice have been produced from an E13.5 CRISPR/cas9 GREB1L mutagenesis. Though no GREB1L mutation has been reported in cardiac malformation, there is evidence that GREB1L is involved in ventricular development. Here, we intorigate evidence that projects GREB1L as a candidate gene of Mayer-Rokitansky-Küster-Hauser Syndrome and propose that functional validation analysis to that effect is imparative.

Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome: a comprehensive update

BACKGROUND

Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome, also referred to as Müllerian aplasia, is a congenital disorder characterized by aplasia of the uterus and upper part of the vagina in females with normal secondary sex characteristics and a normal female karyotype (46,XX).

MAIN BODY

The diagnosis is often made during adolescence following investigations for primary amenorrhea and has an estimated prevalence of 1 in 5000 live female births. MRKH syndrome is classified as type I (isolated uterovaginal aplasia) or type II (associated with extragenital manifestations). Extragenital anomalies typically include renal, skeletal, ear, or cardiac malformations. The etiology of MRKH syndrome still remains elusive, however increasing reports of familial clustering point towards genetic causes and the use of various genomic techniques has allowed the identification of promising recurrent genetic abnormalities in some patients. The psychosexual impact of having MRKH syndrome should not be underestimated and the clinical care foremost involves thorough counselling and support in careful dialogue with the patient. Vaginal agenesis therapy is available for mature patients following therapeutical counselling and education with non-invasive vaginal dilations recommended as first-line therapy or by surgery. MRKH syndrome involves absolute uterine factor infertility and until recently, the only option for the patients to achieve biological motherhood was through gestational surrogacy, which is prohibited in most countries. However, the successful clinical trial of uterus transplantation (UTx) by a Swedish team followed by the first live-birth in September, 2014 in Gothenburg, proofed the first available fertility treatment in MRKH syndrome and UTx is now being performed in other countries around the world allowing women with MRKH syndrome to carry their own child and achieve biological motherhood.

CONCLUSION

Several advances in research across multiple disciplines have been made in the recent years and this kaleidoscopic review provides a current status of various key aspects in MRKH syndrome and provides perspectives for future research and improved clinical care.

Long-term follow-up on MURCS (Müllerian duct, renal, cervical somite dysplasia) association and a review of the literature

Müllerian duct aplasia-renal aplasia-cervicothoracic somite dysplasia (MURCS) association is a unique development disorder with four common types of malformations that include uterine aplasia or hypoplasia, renal ectopy or agenesis, vertebral anomalies, and short stature. The majority of MURCS patients are diagnosed with primary amenorrhea from late-adolescence. However, a few cases with MURCS association are not well diagnosed during childhood and long-term outcomes are not well reported. We report a case of an 8-year-old girl with MURCS association who presented with recurrent urinary tract infections and multiple congenital malformations, and who was followed for 10 years until adulthood. MURCS association should be considered as one of the differential diagnoses when evaluating prepubertal females with vertebral and renal malformations.

Detection of de novo genetic variants in Mayer-Rokitansky-Küster-Hauser syndrome by whole genome sequencing

Objective

The aim of this study was to use whole genome sequencing (WGS) help detect de novo mutations or pathogenic genes of Mayer-Rokitansky-Küster-Hauser syndrome type 1(MRKH syndrome type 1).

Study design

This was a case-parent trios study. Nine unrelated probands, with MRKH syndrome type 1 and their parents were enrolled. The enrollment, sequencing process, establishment of the de novo mutations detecting procedure and experiment part were performed over a 2-year period.

Results

we detected 632 de novo single nucleotide variants (SNVs), 267 de novo small insertions/deletions (indels), 39 de novo structural variations (SVs) and 28 de novo copy number alterations (CNAs). Three novel damaging coding de novo SNVs with three damaging coding de novo genes (PIK3CD, SLC4A10 and TNK2) were revealed. Two SNVs were annotated of the promoter region of gene NBPF10 and 3'UTR of NOTCH2NL, potentially contributing to the pathogenesis of MRKH.

Conclusion

We identified five de novo mutations in BAZ2B, KLHL18, PIK3CD, SLC4A10 and TNK2 by performing WGS, the functional involvement of all deleterious mutations in MRKH candidate genes of the trios warrant further study. WGS may complement conventional array to capture the complete landscape of the genome in MRKH.

Treatment of the Mayer-Rokitansky-Küster-Hauser syndrome with autologous in vitro cultured vaginal tissue: descriptive study of long-term results and patient outcomes

OBJECTIVE

Evaluating sexual function and quality of life (QoL) in patients treated with a modified Abbé-McIndoe technique using in vitro cultured autologous vaginal mucosa.

DESIGN

Descriptive study.

SETTING

Policlinico Umberto I, Sapienza University of Rome.

POPULATION

From 2006 to 2016, 39 women affected by Mayer-Rokitansky-Küster-Hauser syndrome (MRKHS) underwent vaginoplasty at our centre using a modified Abbé-McIndoe technique with in vitro cultured autologous vaginal tissue.

METHODS

For each patient, vaginal tissue was obtained by full-thickness biopsy of the vaginal vestibule. Following enzymatic dissociation, cells were cultured for 2-3 weeks before the transplant.

MAIN OUTCOME MEASURES

Each patient completed two validated questionnaires to quantify sexual function and QoL: the Female Sexual Function Index (FSFI), administered at 12, 36, and 60 months, and the Psychological General Well Being Index (PGWBI) administered at 0, 6, and 36 months after surgery.

RESULTS

Twelve months after surgery, 29 patients were engaging in regular sexual activity. The FSFI test results showed a satisfactory sexual function compared to the general population, with median values of 25.85 (range 4.6-30.5) at 12 months, 27.2 (range 4.4-33.6) at 36 months, and 29.6 (range 23.9-33.6) at 60 months. The PGWBI questionnaire showed a median score of 420.5 (range 108-540) before surgery, and 459 (range 252-533) at the 60-month follow-up.

CONCLUSIONS

Vaginoplasty performed with the use of autologous vaginal tissue, besides ensuring a long-term satisfying sex life, helps in achieving an improvement in QoL that is maintained over time.

TWEETABLE ABSTRACT

Vaginoplasty using in vitro vaginal tissue ensures a satisfactory sexual function and improves quality of life.

Accuracy of anogenital distance and anti-Müllerian hormone in the diagnosis of endometriosis without surgery

OBJECTIVE

To assess the predictive ability of a combination of anogenital distance (AGD) and anti-Müllerian hormone (AMH) to diagnosis the presence of endometriosis without surgery.

METHODS

The present study included women diagnosed with endometriosis and a control group who attended the "Virgen de la Arrixaca" University Hospital, Murcia, Spain, between September 1, 2014, and May 31, 2015. Serum concentrations of AMH were measured, and two AGD measurements were obtained: from the anterior clitoral surface to the upper verge of the anus (AGD_AC ), and from the posterior fourchette to the upper verge of the anus (AGD_AF ). Data were assessed by receiver operator characteristic (ROC) curves.

RESULTS

Women in the endometriosis group (n=57) had significantly shorter AGD_AF (22.8 ± 4.6 vs 27.2 ± 5.7 mm; P<0.001) and lower AMH (2.2 ± 2.5 vs 3.3 ± 1.9 ng/mL; P<0.003) compared with the control group (n=93). Women with serum AMH below the clinical cut-off (1 ng/mL) were 17.40-times more likely to have endometriosis (95% confidence interval [CI] 5.64-53.82). The area under the ROC curve of combined AMH and AGD_AF was 0.77 (95% CI 0.70-0.85).

CONCLUSION

The model for predicting endometriosis on the basis of AMH and AGD could be useful for clinicians and epidemiologists to improve diagnosis and prognosis of this condition.

Congenital Malformations of the Reproductive Tract in a Patient with Poland Syndrome: Is There a Connection?

Background

Poland syndrome and Müllerian duct agenesis (Mayer-Rokitansky-Küster-Hauser(MRKH)-like syndrome) are two rare congenital anomalies with unclear etiology.

Case Report

An 18-year-old female presented with hypoplasia of the left pectoralis muscles and subcutaneous tissue, hypoplasia of the left breast and nipple, and dextrocardia, typical in those with a severe form of Poland syndrome. She also showed aplasia of the vagina and uterus, bilateral ovarian agenesis, and hyperandrogenism, presenting as MRKH-like syndrome.

Conclusion

It is plausible to assume that these two congenital anomalies which arose from distant sites may be interrelated. More cases and further studies will certainly help delineate the pathogenesis of these syndromes.

Intensive vaginal dilation using adjuvant treatments in women with Mayer-Rokitansky-Kuster-Hauser syndrome: retrospective cohort study

AIMS

To evaluate the effect of adjuvants during intensive vaginal dilator therapy for functional and anatomical neovagina creation in women with Mayer-Rokitansky-Kuster-Hauser syndrome (MRKH).

METHODS

This retrospective cohort study included 75 women with MRKH undergoing intensive vaginal dilator treatment between 2000 and 2014. One specialist nurse performed non-surgical vaginal dilation aided by adjuvants, during inpatient admissions for several dilation sessions per day. Following discharge, women continued dilation at home and were advised to attend fortnightly follow-up appointments.

RESULTS

Outcomes from 68 women were analysed. The median age of starting treatment was 18 years (range: 13-36). There was a mean of 3 days per admission (range 1-5) with a median of 10 dilation sessions per admission. Adjuvant treatment was used by 48/68 (71%) women: oestriol cream 29/68 (43%), 50:50 nitrous oxide and oxygen 44/68 (65%), diazepam 8/68 (12%), lidocaine ointment 26/68 (39%), paracetamol 35/68 (51%) and naproxen 2/68 (3%). There were no statistically significant differences for changes in vaginal parameters. Women receiving adjuvants had a median increase of 4.5 cm (0.5-7 cm) in neovaginal length compared with women not receiving adjuvants who had a median increase of 3.25 cm (0-7 cm) during intensive treatment. Women who received adjuvants tolerated more dilation sessions per day (10 vs 6.5 median sessions respectively) than those who did not (P < 0.001). Of those with documented length at discharge, 42/56 (75%) women had an anatomical neovagina of 7 cm or greater length.

CONCLUSIONS

Vaginal dilation delivered by intensive treatment and supplemented by adjuvant treatments in a multi-disciplinary centre is a rapid and effective method for creation of a neovagina in women with MRKH.

Sequence variants in ESR1 and OXTR are associated with Mayer-Rokitansky-Küster-Hauser syndrome

INTRODUCTION

Mayer-Rokitansky-Küster-Hauser syndrome (MRKHS) is characterized by congenital absence of the uterus and the upper two-thirds of the vagina in otherwise phenotypically normal females. It is found isolated or associated with renal, skeletal and other malformations. Despite ongoing research, the etiology is mainly unknown. For a long time, the hypothesis of deficient hormone receptors as the cause for MRKHS has existed, supported by previous findings of our group. The aim of the present study was to identify unknown genetic causes for MRKHS and to compare them with data banks including a review of the literature.

MATERIAL AND METHODS

DNA sequence analysis of the oxytocin receptor (OXTR) and estrogen receptor-1 gene (ESR1) was performed in a group of 93 clinically well-defined patients with uterovaginal aplasia (68 with the isolated form and 25 with associated malformations).

RESULTS

In total, we detected three OXTR variants in 18 MRKHS patients with one leading to a missense mutation, and six ESR1 variants in 21 MRKHS patients, two of these causing amino acid changes and therefore potentially disease.

CONCLUSIONS

The identified variants on DNA level might impair receptor function through different molecular mechanisms. Mutations of ESR1 and OXTR are associated with MRKHS. Thus, we consider these genes potential candidates associated with the manifestation of MRKHS.

Genetics of Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome

Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome, also referred to as Müllerian agenesis, is the second most common cause of primary amenorrhea. It is characterized by congenital absence of the uterus, cervix, and the upper part of the vagina in otherwise phenotypically normal 46,XX females. MRKH syndrome has an incidence of about 1 in 4,500-5,000 newborn females and it is generally divided into two subtypes: MRKH type 1, in which only the upper vagina, cervix and the uterus are affected, and MRKH type 2, which is associated with additional malformations generally affecting the renal and skeletal systems, and also includes MURCS (MÜllerian Renal Cervical Somite) characterized by cervico-thoracic defects. MRKH syndrome is mainly sporadic; however, familial cases have been described indicating that, at least in a subset of patients, MRKH may be an inherited disorder. The syndrome appears to demonstrate an autosomal dominant inheritance pattern, with incomplete penetrance and variable expressivity. The etiology of MRKH syndrome is still largely unknown, probably because of its intrinsic heterogeneity. Several candidate causative genes have been investigated, but to date only WNT4 has been associated with MRKH with hyperandrogenism. This review summarizes and discusses the clinical features and details progress to date in understanding the genetics of MRKH syndrome.

Gonadal agenesis with hypoplastic paramesonephric ducts (PMNDs) derivatives in dizygotic twins

The co-occurrence of gonadal agenesis alongside hypoplastic derivatives of the paramesonephric ducts has rarely been observed.

PATIENT(S)

16-year-old dizygotic twin sisters were referred to our department because of primary amenorrhea. X-ray, bone densitometry, ultrasonography, pelvic MRI and measurement of pituitary, ovary, and thyroid hormones were performed. Both twins showed hypergonadotropic hypogonadism, bilateral gonadal agenesis, fallopian tube, uterus, and vaginal hypoplasia but normal kidney and urinary tract structures and skeletal system. Analysis of Q-banded chromosomes in peripheral blood for the search for centromeric X-chromosome DNA and SRY gene was normal as well as the molecular analysis of FMR1, GDF9, and BMP15 genes. Estradiol gel was administered for one year followed by estroprogestin treatment. Both twins growth increased; breast development was stimulated and first menses occurred. Deregulation in the expression of the various HOX genes along the axis of the developing reproductive tract in a determinate time of development may be one of the mechanisms involved in the origin of this complex and rare association.

Etiologies of uterine malformations

Ranging from aplastic uterus (including Mayer-Rokitansky-Kuster-Hauser syndrome) to incomplete septate uterus, uterine malformations as a group are relatively frequent in the general population. Specific causes remain largely unknown. Although most occurrences ostensibly seem sporadic, familial recurrences have been observed, which strongly implicate genetic factors. Through the study of animal models, human syndromes, and structural chromosomal variation, several candidate genes have been proposed and subsequently tested with targeted methods in series of individuals with isolated, non-isolated, or syndromic uterine malformations. To date, a few genes have garnered strong evidence of causality, mainly in syndromic presentations (HNF1B, WNT4, WNT7A, HOXA13). Sequencing of candidate genes in series of individuals with isolated uterine abnormalities has been able to suggest an association for several genes, but confirmation of a strong causative effect is still lacking for the majority of them. We review the current state of knowledge about the developmental origins of uterine malformations, with a focus on the genetic variants that have been implicated or associated with these conditions in humans, and we discuss potential reasons for the high rate of negative results. The evidence for various environmental and epigenetic factors is also reviewed. © 2016 Wiley Periodicals, Inc.

Candidate gene analysis in a case of congenital absence of the endometrium

Background

Primary amenorrhea usually result from a genetic or anatomic abnormality. We present the first reported patient with the absence of endometrium and lumen in a small bicornuate uterus in a patient with primary amenorrhea.

Case presentation

A 41-year-old woman presented for evaluation of primary amenorrhea and infertility. She did develop normal secondary sexual characteristics but never had menses. Physical examination, hormone analyses, and karyotype analysis were normal. Transvaginal ultrasonography revealed a small uterus with absent endometrial stripe. Ovaries were normal in size. Pathology from hysterectomy for abnormal Pap smears revealed a hypoplastic bicornuate uterus with absence of lumen and absent endometrium. DNA analyses for mutations in the coding sequences of three members of HOXA gene family was performed, but no variants in the coding sequence of these genes were found. These findings support the hypothesis that mutations in the coding sequence of HOXA10, HOXA11, and HOXA13 are not responsible for congenital endometrial absence with bicornuate hypoplastic uterus.

Conclusions

Congenital absence of the endometrium is an uncommon etiology for primary amenorrhea, and nonvisualization of the endometrial stripe on ultrasound imaging in association with primary amenorrhea should raise suspicion of this rare disorder in this case.

Associations of Polymorphisms in WNT9B and PBX1 with Mayer-Rokitansky-Küster-Hauser Syndrome in Chinese Han

BACKGROUND

Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome is a rare syndrome that is characterized by congenital aplasia of the uterus and the upper portion (2/3) of the vagina. Previous attempts to identify causal mutations of MRKH syndrome have primarily resulted in negative outcomes. We investigated whether these reported variants are associated with MRKH syndrome (types I and II) in a relatively large sample size of Chinese Han patients, and whether any gene-gene epistatic interactions exist among these variants.

METHODS

This study included 182 unrelated Chinese women with MRKH syndrome (155 with type I and 27 with type II) and 228 randomized female controls. Seventeen candidate loci in the AMH, PBX1, WNT4, WNT7A, WNT9B, HOXA10, HOXA11, LHXA1 and GALT genes were genotyped using the Sequenom MassARRAY iPLEX platform. Single-marker association, additive effects and multifactor interactions were investigated.

RESULTS

The gene frequency distributions of MRKH type 1 and type 2 were similar. Rs34072914 in WNT9B was found to be associated with MRKH syndrome (P = 0.024, OR = 2.65, 95%CI = 1.14-6.17). The dominant models of rs34072914 and rs2275558 in WNT9B and PBX1, respectively, were significantly associated with MRKH syndrome risk in the Chinese Han patients. Additive gene-gene interaction analyses indicated a significant synergetic interaction between WNT9B and PBX1 (RERI = 1.397, AP = 0.493, SI = 4.204). Multifactor dimensionality reduction (MDR) analysis revealed novel dimensional epistatic four-gene effects (AMH, PBX1, WNT7A and WNT9B) in MRKH syndrome.

CONCLUSIONS

This association study successfully identified two susceptibility SNPs (WNT9B and PBX1) associated with MRKH syndrome risk, both separately and interactively. The discovery of a four-gene epistatic effect (AMH, PBX1, WNT7A and WNT9B) in MRKH syndrome provides novel information for the elucidation of the genetic mechanism underlying the etiology of MRKH syndrome.

Concurrent exome-targeted next-generation sequencing and single nucleotide polymorphism array to identify the causative genetic aberrations of isolated Mayer-Rokitansky-Küster-Hauser syndrome

STUDY QUESTION

Can the use of whole-exome sequencing (WES) together with single nucleotide polymorphism (SNP) array help to identify novel causative genes of isolated Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome?

SUMMARY ANSWER

OR4M2 (olfactory receptor, family 4, subfamily M, member 2) and PDE11A (phosphodiesterase 11A) gene loss-of-function variants as well as deletions at 15q11.2, 19q13.31, 1p36.21, and 1q44 were identified as possible commonly altered regions in patients with type 1 MRKH.

WHAT IS KNOWN ALREADY

The isolated form of Müllerian aplasia is the most common subtype of MRKH syndrome, which invariably leads to difficulties producing offspring in affected women. However, there is little information currently available to allow for genetic testing and counseling to be performed for those affected by this syndrome.

STUDY DESIGN, SIZE AND DURATION

This was a case-series genetic study. A total of seven consecutive unrelated women with type 1 MRKH were enrolled. The enrollment and experimental procedures were performed over a 2-year period.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Whole exome-targeted next-generation sequencing and SNP array (Affymetrix Genome-Wide Human SNP Array 6.0) were performed on the first five unrelated women with type 1 MRKH syndrome. The data were combined, and the '3-hit principal' was applied on a genome-wide scale to search for the common causative genes. Quantitative PCR (qPCR) and Sanger sequencing were used to validate the identified genomic copy number losses and variants. Replication tests using direct Sanger sequencing and qPCR were performed on the remaining two women with type 1 MRKH syndrome to support the credibility of the potential candidate genes and deletions.

MAIN RESULTS AND THE ROLE OF CHANCE

A total of 3443 damaging variants based on WES were shown to intersect with 1336 copy number variations (deletions) derived from the SNP array. Four highly recurrent deletions at 15q11.2 (80%), 19q13.31 (40%), 1p36.21 (40%) and 1q44 (40%) were identified in the first five women with type 1 MRKH syndrome and were considered to be novel candidate aberrations. A previously reported 1q21.1 deletion was also recurrent in two of the first five women with type 1 MRKH syndrome. The 1q44 and 19q13.31 deletions were present in at least one of the two additional patients. Damaging variants were detected in HNRNPCL1 (heterogeneous nuclear ribonucleoprotein C-like 1), OR2T2 (olfactory receptor, family 2, subfamily T, member 2), OR4M2, ZNF816 (zinc finger protein 816), and PDE11A in several of the initial five patients. Among these, the damaging variants of OR4M2 (located at 15q11.2) and PDE11A were found in at least one of the two additional patients with type 1 MRKH.

LIMITATIONS, REASONS FOR CAUTION

In this study, we only searched for the deletions or damaging variants causing loss-of-function of genes in at least three of the initial five patients (3-hit criteria). Therefore, the study was designed to only detect common causative genes. Genomic duplications and/or rare individual mutations that may have also contributed to MRKH syndrome were not investigated.

WIDER IMPLICATIONS OF THE FINDINGS

This study demonstrated the feasibility of the use of combined data from both WES and SNP arrays for the identification of possible common causative genetic aberrations in patients with type 1 MRKH syndrome on a genome-wide scale. Further validation of our found causative genes is required before applying on genetic testing and counseling.

STUDY FUNDING/COMPETING INTERESTS

The study was supported by grants from the National Science Council of Taiwan (NSC98-2314-B002-105-MY3 and NSC 100-2314-B002-027-MY3). The funding sources had no involvement in the design or analysis of the study. The authors have no competing interests to declare.

TRIAL REGISTRATION NUMBER

Not applicable.

Discordant Mayer-Rokitansky-Kuster-Hauser (MRKH) syndrome in identical twins - a case report and implications for reproduction in MRKH women

Infertility has previously been considered as an inevitable consequence of Mayer-Rokitansky-Kuster-Hauser (MRKH) syndrome. With modern assisted reproductive technology (ART) techniques becoming increasingly accessible, MRKH women have the opportunity for their own genetic offspring. The availability of such technology, however, increases the importance of understanding the aetiology of this complex condition. The literature debating the relevance of genetic versus post-zygotic events in the aetiology of MRKH syndrome is reviewed in the context of this report of monozygotic twins discordant for MRKH syndrome.

Genetics of female infertility due to anomalies of the ovary and mullerian ducts

Genetic factors are pivotal in reproductive development and subsequent reproductive processes. If disturbed, infertility can occur. In the female, genetic factors affecting the ovary and the uterus are not uncommon causes of infertility. Terminal deletions on the X long arm and X short arm and X chromosomal mosaicism have long been accepted as causes of premature ovarian failure (POF). Responsible genes on the X have not yet elucidated. Attractive candidate genes for POF also exist on autosomes, and in over a dozen genes molecular perturbations are documented in non-syndromic POF. The most common single-gene cause of POF is premutation carriers for FMR1 (fragile X syndrome). As other candidate genes and additional ethnic groups are interrogated, the proportion of POF cases due to single-gene mutation will increase. Among uterine anomalies, incomplete mullerian fusion is most common. Increased recurrence risks for first-degree relatives confirm a role for genetic factors; interrogation of candidate genes is under way.

Mutation screening of HOXA7 and HOXA9 genes in Chinese women with Müllerian duct abnormalities

HOXA genes in groups 7-13 have been proven to play a role in determining positional identity along the genitalia axis. The aim of the present study was to explore the relationship between HOXA7 and HOXA9 mutations and Müllerian duct abnormalities (MDA). One hundred and ninety-two Chinese patients with MDA abnormalities and 192 healthy controls were recruited. All coding regions of HOXA7 and HOXA9 were amplified and sequenced directly. Rs2301721 and rs2301720 in HOXA7, rs35355140 and rs7810502 in HOXA9 were identified in patients with MDA and controls. One rare single nucleotide polymorphism rs189587233 in 3' UTR of HOXA9 gene was detected in one patient with didelphic uterus and absent in the 192 controls. This polymorphism, however, is known to exist in the normal Chinese population. Our results indicated that variants in the HOXA7 and HOXA9 genes were not common in Chinese women with Müllerian duct abnormalities.

The genetics of Mullerian aplasia

Mayer-Rokitansky-Kuster-Hauser (MRKH) syndrome consists of Mullerian aplasia with or without other anomalies, most commonly renal and skeletal. The genetic etiology of MRKH syndrome is unknown for most patients, but supportive evidence exists for heterozygous mutations in WNT4, LHX1, and HNF1B. Chromosomal microarray analyses have demonstrated chromosomal regions with copy number variants in multiple patients - deletions in17q12 and 16p11.2, and either deletions or duplications in 22q11.2. Genomic analyses of expression and methylation have also suggested potential molecular pathways. Positional cloning in MRKH patients with chromosomal rearrangements and exome sequencing are likely to result in new genes. Although some single gene defects and copy number variant regions have been identified, the molecular basis for the vast majority of MRKH remains unknown.

Gene expression profile of patients with Mayer-Rokitansky-Küster-Hauser syndrome: new insights into the potential role of developmental pathways

Mayer-Rokitansky-Küster-Hauser syndrome (MRKHS) is a rare disease characterized by congenital aplasia of uterus and vagina. Although many studies have investigated several candidate genes, up to now none of them seem to be responsible for the aetiology of the syndrome. In our study, we identified differences in gene expression profile of in vitro cultured vaginal tissue of MRHKS patients using whole-genome microarray analysis. A group of eight out of sixteen MRKHS patients that underwent reconstruction of neovagina with an autologous in vitro cultured vaginal tissue were subjected to microarray analysis and compared with five healthy controls. Results obtained by array were confirmed by qRT-PCR and further extended to other eight MRKHS patients. Gene profiling of MRKHS patients delineated 275 differentially expressed genes, of which 133 downregulated and 142 upregulated. We selected six deregulated genes (MUC1, HOXC8, HOXB2, HOXB5, JAG1 and DLL1) on the basis of their fold change, their differential expression in most patients and their relevant role in embryological development. All patients showed upregulation of MUC1, while HOXB2 and HOXB5 were downregulated, as well as Notch ligands JAG1 and DLL1 in the majority of them. Interestingly, HOXC8 was significantly upregulated in 47% of patients, with a differential expression only in MRKHS type I patients. Taken together, our results highlighted the dysregulation of developmental genes, thus suggesting a potential alteration of networks involved in the formation of the female reproductive tract and providing a useful clue for understanding the pathophysiology of MRKHS.

Analysis of WNT9B mutations in Chinese women with Mayer-Rokitansky-Küster-Hauser syndrome

Mayer–Rokitansky–Küster–Hauser (MRKH) syndrome is a rare congenital female genital anomaly, which is caused by aplasia of the caudalportion of the Müllerian duct. The WNT9B gene encodes a secretory glycoprotein essential for the caudal extension of the Müllerian duct during embryonic development in mice. Coding regions and exon/intron boundaries of the WNT9B gene were amplified and sequenced in 42 Chinese women with MRKH syndrome and 42 controls. Two novel heterozygous mutationswere identified,which were absent in controls. Onewas amissensemutation in exon 1, and the other was located in the 30-untranslated region. Both variants were detected in one out of 42 patients. The two novel mutations may be pathogenic variants in MRKH patients and warrant further functional study.

HOXA10 and HOXA13 sequence variations in human female genital malformations including congenital absence of the uterus and vagina

Congenital genital malformations occurring in the female population are estimated to be 5 per 1000 and associate with infertility, abortion, stillbirth, preterm delivery and other organ abnormalities. Complete aplasia of the uterus, cervix and upper vagina (Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome) has an incidence of 1 per 4000 female live births. The molecular etiology of congenital genital malformations including MRKH is unknown up to date. The homeobox (HOX) genes HOXA10 and HOXA13 are involved in the development of human genitalia. In this investigation, HOXA10 and HOXA13 genes of 20 patients with the MRKH syndrome, 7 non-MRKH patients with genital malformations and 53 control women were sequenced to assess for DNA variations. A total of 14 DNA sequence variations (10 novel and 4 known) within exonic and untranslated regions were detected in HOXA10 and HOXA13 among our cohorts. Four HOXA10 and two HOXA13 DNA sequence variations were found solely in patients with genital malformations. In addition to mutations resulting in synonymous amino acid substitutions, in the HOXA10 gene a missense mutation was identified and predicted by computer analysis as probably damaging to protein function in two non-MRKH patients, one with a bicornate and the other patient with a septated uterus. A novel exonic HOXA10 cytosine deletion was also identified in a non-MRKH patient with a septate uterus and renal malformations resulting in a premature stop codon and loss of the homeodomain helix 3/4. This cytosine deletion and the missense mutation in HOXA10 were analysed by real time PCR and sequencing, respectively, in two additional larger cohorts of 103 patients with MRKH and 109 non-MRKH patients with genital malformations. No other patients were found with the cytosine deletion however one additional patient was identified regarding the missense mutation. Rare DNA sequence variations in the HOXA10 gene could contribute to the misdevelopment of female internal genitalia.

Impact of endocrine-disrupting compounds (EDCs) on female reproductive health

Evidence is accumulating that environmental chemicals (ECs) including endocrine-disrupting compounds (EDCs) can alter female reproductive development, fertility and onset of menopause. While not as clearly defined as in the male, this set of abnormalities may constitute an Ovarian Dysgenesis Syndrome with at least some origins of the syndrome arising during foetal development. ECs/EDCs have been shown to affect trophoblast and placental function, the female hypothalamo-pituitary-gonadal axis, onset of puberty and adult ovarian function. The effects of ECs/EDCs are complex, not least because it is emerging that low-level, 'real-life' mixtures of ECs/EDCs may carry significant biological potency. In addition, there is evidence that ECs/EDCs can alter the epigenome in a sexually dimorphic manner, which may lead to changes in the germ line and perhaps even to transgenerational effects. This review summarises the evidence for EC, including EDC, involvement in female reproductive dysfunction, it highlights potential mechanisms of EC action in the female and emphasises the need for further research into EC effects on female development and reproductive function.

PAX2 in 192 Chinese women with Müllerian duct abnormalities: mutation analysis

The paired box gene 2 (PAX2) has been proven to be a crucial gene during organogenesis of the urogenital system in mice models. This study was aimed to explore the relationship between PAX2 mutations and human Müllerian duct abnormalities (MDA). A total of 192 Chinese MDA patients (15 cases of uterine aplasia and 177 of incomplete Müllerian fusion) and 192 ethnic-matched controls were recruited from 2009 to 2011. Coding regions of PAX2 of MDA cases were amplified and sequenced. One rare novel synonymous variant (c.320G>A) was discovered in one patient with uterus didelphys, whereas this variant was not found in the control group. Mutations in PAX2 may be not a common cause of MDA.

Mutations in WNT4 are not responsible for Müllerian duct abnormalities in Chinese women

The WNT4 gene plays a crucial role in sexual differentiation and female genital tract development. This study screened WNT4 for mutation in 189 Chinese women with Müllerian duct abnormalities (10 Mayer-Rokitansky-Küster-Hauser syndrome, five Müllerian aplasia and 174 incomplete Müllerian fusion) and detected no perturbation that would indicate a major role for WNT4. Only one novel synonymous mutation (c.1091G>A) in exon 5 and one known single-nucleotide polymorphism (rs16826648) in exon 2 were found. The results suggest that WNT4 might not contribute to the aetiology of Müllerian duct abnormalities in Chinese women.

Mayer-rokitansky-kuster-hauser syndrome: surgical management of two cases

The Mayer-Rokitansky-Kuster-Hauser (MRKH) Syndrome is a rare anomaly characterized by congenital aplasia of the uterus and vagina in women showing normal development of secondary sexual characters and normal 44 XX karyotype. We report our experience in the management of two patients with congenital absence of the vagina due to the MRKH syndrome. The first case was a 24-year-old student, who presented with primary amenorrhea, uterovaginal agenesis, right pelvi-ureteric junction obstruction, and left renal agenesis. The second patient was a 24-year-old housewife, who presented with primary amenorrhea and inability to achieve penetrative sexual intercourse. She had vaginal atresia and a grossly hypoplastic uterus. Both had successful sigmoid colovaginoplasty and are sexually active. Vaginal reconstruction using the sigmoid colon saw an immediate and satisfactory outcome in both patients.

Analysis of PBX1 mutations in 192 Chinese women with Müllerian duct abnormalities

We examined the PBX1 gene in 192 Chinese women with Müllerian duct abnormalities and revealed 2 known single nucleotide polymorphisms: c.61 > A in exon 1 and c.998-1330A>G in intron 7. Future studies in large cohorts of different ethnic populations are warranted to establish definite associations between the PBX1 gene and Müllerian duct abnormalities.

A combination of transcriptome and methylation analyses reveals embryologically-relevant candidate genes in MRKH patients

BACKGROUND

The Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome is present in at least 1 out of 4,500 female live births and is the second most common cause for primary amenorrhea. It is characterized by vaginal and uterine aplasia in an XX individual with normal secondary characteristics. It has long been considered a sporadic anomaly, but familial clustering occurs. Several candidate genes have been studied although no single factor has yet been identified. Cases of discordant monozygotic twins suggest that the involvement of epigenetic factors is more likely.

METHODS

Differences in gene expression and methylation patterns of uterine tissue between eight MRKH patients and eight controls were identified using whole-genome microarray analyses. Results obtained by expression and methylation arrays were confirmed by qRT-PCR and pyrosequencing.

RESULTS

We delineated 293 differentially expressed and 194 differentially methylated genes of which nine overlap in both groups. These nine genes are mainly embryologically relevant for the development of the female genital tract.

CONCLUSION

Our study used, for the first time, a combined whole-genome expression and methylation approach to reveal the etiology of the MRKH syndrome. The findings suggest that either deficient estrogen receptors or the ectopic expression of certain HOXA genes might lead to abnormal development of the female reproductive tract. In utero exposure to endocrine disruptors or abnormally high maternal hormone levels might cause ectopic expression or anterior transformation of HOXA genes. It is, however, also possible that different factors influence the anti-Mullerian hormone promoter activity during embryological development causing regression of the Müllerian ducts. Thus, our data stimulate new research directions to decipher the pathogenic basis of MRKH syndrome.

Recurrent microdeletion at 17q12 as a cause of Mayer-Rokitansky-Kuster-Hauser (MRKH) syndrome: two case reports

BACKGROUND

Mayer-Rokitansky-Kuster-Hauser syndrome (MRKH) consists of congenital aplasia of the uterus and the upper part of vagina due to anomalous development of Müllerian ducts, either isolated or associated with other congenital malformations, including renal, skeletal, hearing and heart defects. This disorder has an incidence of approximately 1 in 4500 newborn girls and the aetiology is poorly understood.

METHODS AND RESULTS

we report on two patients affected by MRKH syndrome in which array-CGH analysis disclosed an identical deletion spanning 1.5 Mb of genomic DNA at chromosome 17q12. One patient was affected by complete absence of uterus and vagina, with bilaterally normal ovaries, while the other displayed agenesis of the upper part of vagina, right unicornuate uterus, non cavitating rudimentary left horn and bilaterally multicystic kidneys. The deletion encompassed two candidate genes, TCF2 and LHX1. Mutational screening of these genes in a selected group of 20 MRKH females without 17q12 deletion was negative.

CONCLUSION

Deletion 17q12 is a rare albeit recurrent anomaly mediated by segmental duplications, previously reported in subjects with developmental kidney abnormalities and diabetes. The present two patients expand the clinical spectrum associated with this imbalance and suggest that this region is a candidate locus for a subset of MRKH syndrome individuals, with or without renal defects.

Müllerian duct anomalies: review of current management

The aim of this paper was to discuss the embryological aspects of Müllerian duct anomalies and to analyze the current diagnostic methods and therapy. Müllerian anomalies are congenital defects of the female reproductive tract resulting from failure in the development of the Müllerian ducts and their associated structures. Their cause has yet to be fully clarified, and it is currently believed to be multifactorial. Symptoms appear principally during adolescence or early adulthood, and affect the reproductive capacity of these women. When clinically suspected, investigations leading to diagnosis include imaging methods such as hysterosalpingography, ultrasonography and magnetic resonance. The classification of these malformations relates to their embryogenesis, and defines the therapy and prognosis. Müllerian anomalies consist of a wide range of defects that may vary from patient to patient. Therefore, their management must also be individual, taking anatomical and clinical characteristics into consideration, as well as the patient's wishes.

Mayer-Rokitansky-Kuster-Hauser syndrome: recent clinical and genetic findings

Mayer-Rokitansky-Kuster-Hauser (MRKH) syndrome is characterized by Mullerian duct aplasia in an XX individual with female phenotype presenting primary amenorrhea at adolescence. Multiple abnormalities may be associated with the MRKH syndrome. Genetic investigations focused on the genes of anti-Mullerian hormone and its receptor, as well as on Wt1, Pax2, Cftr and Hox genes, have been unproductive. Only the Wnt4 gene has been clearly implicated in MRKH syndrome and found to be associated with clinical and/or biological signs of hyperandrogenism in three different works. Beside the multiple malformations that may be associated with MRKH syndrome, such as renal, skeletal, cardiac and auditory defects, MRKH and hyperandrogenism represent a new clinical and genetic disorder.

Molecular analysis of the beta-catenin gene in patients with the Mayer-Rokitansky-Küster-Hauser syndrome

PURPOSE

To study the beta-catenin gene in a group of Mayer-Rokitansky-Küster-Hauser patients.

METHODS

Twelve patients with the Mayer-Rokitansky-Küster-Hauser syndrome were included in this study. DNA was extracted from peripheral blood and the region codifying beta-catenin GSK-3beta phosphorylation sites on exon 3 was amplified. PCR products were purified and directly sequenced.

RESULTS

No mutations were found in the GSK-3beta phosphorylation sites on exon 3 of beta-catenin gene in this group of patients with the MRKH syndrome.

CONCLUSIONS

beta-catenin gene mutations are an unlikely cause of the MRKH syndrome.

[The Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome: clinical description and genetics]

The Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome is characterized by congenital aplasia of the uterus and the upper part (two-third) of the vagina. It may be isolated (type I) or associated with other malformations (type II or MURCS association). These latter involve the upper urinary tract, the skeleton and, to a lesser extent, the otologic sphere or the heart. The incidence of MRKH syndrome has been estimated as 1 in 4500 women. The prime feature is a primary amenorrhea in women presenting otherwise with normal development of secondary sexual characteristics and normal external genitalia. However, the vagina is reduced to a vaginal dimple with variable depth. The ovaries are normal and functional as well as the endocrine status. Karyotype is 46,XX, with no visible chromosome modification. The phenotypic manifestations of MRKH syndrome overlap with various other syndromes or malformations and thus require accurate delineation as well as differential diagnosis. For a long time, the syndrome has been considered as a sporadic anomaly, but increasing familial cases now support the hypothesis of a genetic cause currently under investigation. The syndrome appears to be transmitted as an autosomal dominant trait with incomplete penetrance and variable expressivity.