High incidence of recurrent copy number variants in patients with isolated and syndromic Müllerian aplasia

Heterozygous ZNHIT3 variants within the 17q12 recurrent deletion region are associated with Mayer-Rokitansky-Kuster Hauser (MRKH) syndrome

The molecular basis of mullerian aplasia, also known as Mayer-Rokitansky-Kuster Hauser (MRKH) or congenital absence of the uterus and vagina, is largely unknown. We applied a multifaceted genetic approach to studying the pathogenesis of MRKH including exome sequencing of trios and duos, genome sequencing of families, qPCR, RT-PCR, and Sanger sequencing to detect intragenic deletions, insertions, splice variants, single nucleotide variants, and rearrangements in 132 persons with MRKH. We identified two heterozygous variants in ZNHIT3 localized to a commonly involved CNV region at chromosome 17q12 in two different families with MRKH. One is a frameshift, truncating variant that is predicted to interfere with steroid hormone binding of the LxxLL sequence of the C-terminal region. The second variant is a double missense/stopgain variant. Both variants impair protein expression in vitro. In addition, four more probands with MRKH harbored the stopgain variant without the nearby missense variant. In total, 6/132 (4.5%) of patients studied, including five with associated anomalies (type 2 MRKH), had ZNHIT3 variants that impair function in vitro. Our findings implicate ZNHIT3 as an important gene associated with MRKH within the 17q12 CNV region.

46,XX Differences of Sex Development outside congenital adrenal hyperplasia: pathogenesis, clinical aspects, puberty, sex hormone replacement therapy and fertility outcomes

The term 'differences of sex development' (DSD) refers to a group of congenital conditions that are associated with atypical development of chromosomal, gonadal, and/or anatomical sex. DSD in individuals with a 46,XX karyotype can occur due to fetal or postnatal exposure to elevated amount of androgens or maldevelopment of internal genitalia. Clinical phenotype could be quite variable and for this reason these conditions could be diagnosed at birth, in newborns with atypical genitalia, but also even later in life, due to progressive virilization during adolescence, or pubertal delay. Understand the physiological development and the molecular bases of gonadal and adrenal structures is crucial to determine the diagnosis and best management and treatment for these patients. The most common cause of DSD in 46,XX newborns is congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency, determining primary adrenal insufficiency and androgen excess. In this review we will focus on the other rare causes of 46,XX DSD, outside CAH, summarizing the most relevant data on genetic, clinical aspects, puberty and fertility outcomes of these rare diseases.

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.

A Case of Chromosome 17q12 Deletion Syndrome with Type 2 Mayer-Rokitansky-Küster-Hauser Syndrome and Maturity-Onset Diabetes of the Young Type 5

Chromosome 17q12 deletion syndrome (OMIM #614527) is a rare genetic disorder associated with a heterozygous 1.4-1.5 Mb deletion at chromosome 17q12, leading to a spectrum of clinical manifestations, including kidney abnormalities, neurodevelopmental delay, maturity-onset diabetes of the young type 5 (MODY5), and Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome. We present the case of a 14-year-old Korean female diagnosed with chromosome 17q12 deletion syndrome, confirmed by chromosomal microarray analysis. The patient exhibited MODY5 with pancreatic agenesis, MRKH syndrome, dysmorphic facial features, developmental delay, kidney rotation anomaly, portal vein thrombosis with liver hypoplasia, short stature, and scoliosis. Management involved the initiation of multiple daily insulin injections for diabetes control, gynecological evaluation for MRKH syndrome, and multidisciplinary care for associated complications. This case highlights the complexity and varied organ involvement in chromosome 17q12 deletion syndrome. A comprehensive and multidisciplinary approach is crucial for the management of affected individuals, including regular monitoring, tailored interventions across various medical specialties, and providing psychosocial support.

A Cohort of 469 Mayer-Rokitansky-Küster-Hauser Syndrome Patients-Associated Malformations, Syndromes, and Heterogeneity of the Phenotype

The Mayer-Rokitansky-Küster-Hauser syndrome is characterized by aplasia of the uterus and upper two-thirds of the vagina. While it can appear as an isolated genital malformation, it is often associated with extragenital abnormalities, with little still known about the pathogenetic background. To provide an overview of associated malformations and syndromes as well as to examine possible ties between the rudimentary tissue and patient characteristics, we analyzed a cohort of 469 patients with MRKHS as well as 298 uterine rudiments removed during surgery. A total of 165 of our patients (35.2%) had associated malformations (MRKHS type II). Renal defects were the most common associated malformation followed by skeletal abnormalities. Several patients had atypical associated malformations or combined syndromes. Uterine rudiments were rarer in patients with associated malformations than in patients without them. Rudiment size ranged from 0.3 cm3 to 184.3 cm3 with a mean value of 7.9 cm3. Importantly, MRKHS subtype or concomitant malformations were associated with a different frequency of uterine tissue as well as a different rudiment size and incidence of endometrial tissue, thereby indicating a clear heterogeneity of the phenotype. Further research into the associated molecular pathways and potential differences between MRKHS subtypes is needed.

Recurrent human 16p11.2 microdeletions in type I Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome patients in Chinese Han population

BACKGROUNDS

Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome, a severe congenital malformation of the female genital tract, is a highly heterogeneous disease which has no clear etiology. Previous studies have suggested that copy number variations (CNVs) and single-gene mutations might contribute to the development of MRKH syndrome. In particular, deletions in 16p11.2, which are suggested to be involved in several congenital diseases, have been reported in Chinese type II MRKH patients and European MRKH patients. However, few CNVs including 16p11.2 microdeletions were identified in Chinese type I MRKH cases although it accounted for the majority of MRKH patients in China. Thus, we conducted a retrospective study to identify whether CNVs at human chromosome 16p11.2 are risk factors of type I MRKH syndrome in the Chinese Han population.

METHODS

We recruited 143 patients diagnosed with type I MRKH between 2012 and 2014. Five hundred unrelated Chinese without congenital malformation were enrolled in control group, consisting of 197 from the 1000 Genomes Project and 303 from Fudan University. Quantitative PCR, array comparative genomic hybridization, and sanger sequencing were conducted to screen and verify candidate variant.

RESULTS

Our study identified recurrent 16p11.2 microdeletions of approximately 600 kb in two out of the 143 type I MRKH syndrome patients using high-density array-based comparative genomic hybridization (aCGH), while no 16p11.2 deletion was found in the control group. We did not find any mutations in TBX6 gene in our samples.

CONCLUSIONS

The results of the study identify 16p11.2 deletion in Chinese MRKH I patients for the first time, as well as support the contention that 16p11.2 microdeletions are associated with MRKH syndrome in both types across populations. It is suggested that 16p11.2 microdeletions should be included in molecular diagnosis and genetic counseling of female reproductive tract disorders.

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.

Homozygous 22q11.2 distal type II microdeletion is associated with syndromic neurodevelopmental delay

Genomic disorders result from heterozygous copy number variants (CNVs). Homozygous deletions spanning numerous genes are rare, despite the potential contribution of consanguinity to such instances. CNVs in the 22q11.2 region are mediated by nonallelic homologous recombination between pairs of low copy repeats (LCRs), from amongst eight LCRs designated A-H. Heterozygous distal type II deletions (LCR-E to LCR-F) have incomplete penetrance and variable expressivity, and can lead to neurodevelopmental issues, minor craniofacial anomalies, and congenital abnormalities. We report siblings with global developmental delay, hypotonia, minor craniofacial anomalies, ocular abnormalities, and minor skeletal issues, in whom chromosomal microarray identified a homozygous distal type II deletion. The deletion was brought to homozygosity as a result of a consanguineous marriage between two heterozygous carriers of the deletion. The phenotype of the children was strikingly more severe and complex than that of the parents. This report suggests that the distal type II deletion harbors a dosage-sensitive gene or regulatory element, which leads to a more severe phenotype when deleted on both chromosomes.

Functional genomics analysis identifies loss of HNF1B function as a cause of Mayer-Rokitansky-Küster-Hauser syndrome

Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome is a congenital condition characterized by aplasia or hypoplasia of the uterus and vagina in women with a 46,XX karyotype. This condition can occur as type I when isolated or as type II when associated with extragenital anomalies including kidney and skeletal abnormalities. The genetic basis of MRKH syndrome remains unexplained and several candidate genes have been proposed to play a role in its etiology, including HNF1B, LHX1 and WNT4. Here, we conducted a microarray analysis of 13 women affected by MRKH syndrome, resulting in the identification of chromosomal changes, including the deletion at 17q12, which contains both HNF1B and LHX1. We focused on HNF1B for further investigation due to its known association with, but unknown etiological role in, MRKH syndrome. We ablated Hnf1b specifically in the epithelium of the Müllerian ducts in mice and found that this caused hypoplastic development of the uterus, as well as kidney anomalies, closely mirroring the MRKH type II phenotype. Using single-cell RNA sequencing of uterine tissue in the Hnf1b-ablated embryos, we analyzed the molecules and pathways downstream of Hnf1b, revealing a dysregulation of processes associated with cell proliferation, migration and differentiation. Thus, we establish that loss of Hnf1b function leads to an MRKH phenotype and generate the first mouse model of MRKH syndrome type II. Our results support the investigation of HNF1B in clinical genetic settings of MRKH syndrome and shed new light on the molecular mechanisms underlying this poorly understood condition in women's reproductive health.

Rare structural variants, aneuploidies, and mosaicism in individuals with Mullerian aplasia detected by optical genome mapping

The molecular basis of Mayer-Rokitansky-Kuster-Hauser (MRKH) syndrome remains largely unknown. Pathogenic variants in WNT4 and HNF1B have been confirmed in a small percent of individuals. A variety of copy number variants have been reported, but causal gene(s) remain to be identified. We hypothesized that rare structural variants (SVs) would be present in some individuals with MRKH, which could explain the genetic basis of the syndrome. Large molecular weight DNA was extracted from lymphoblastoid cells from 87 individuals with MRKH and available parents. Optical genome mapping (OGM) was performed to identify SVs, which were confirmed by another method (quantitative PCR, chromosomal microarray, karyotype, or fluorescent in situ hybridization) when possible. Thirty-four SVs that overlapped coding regions of genes with potential involvement in MRKH were identified, 14 of which were confirmed by a second method. These 14 SVs were present in 17/87 (19.5%) of probands with MRKH and included seven deletions, three duplications, one new translocation in 5/50 cells-t(7;14)(q32;q32), confirmation of a previously identified translocation-t(3;16)(p22.3;p13.3), and two aneuploidies. Of interest, three cases of mosaicism (3.4% of probands) were identified-25% mosaicism for trisomy 12, 45,X(75%)/46,XX (25%), and 10% mosaicism for a 7;14 translocation. Our study constitutes the first systematic investigation of SVs by OGM in individuals with MRKH. We propose that OGM is a promising method that enables a comprehensive investigation of a variety of SVs in a single assay including cryptic translocations and mosaic aneuploidies. These observations suggest that mosaicism could play a role in the genesis of MRKH.

Copy number variants suggest different molecular pathways for the pathogenesis of bladder exstrophy

Bladder exstrophy is a rare congenital malformation leaving the urinary bladder open in the midline of the abdomen at birth. There is a clear genetic background with chromosome aberrations, but so far, no consistent findings apart from 22q11-duplications detected in about 2%-3% of all patients. Some genes are implicated like the LZTR1, ISL1, CELSR3, and the WNT3 genes, but most are not explained molecularly. We have performed chromosomal microarray analysis on a cohort of 140 persons born with bladder exstrophy to look for submicroscopic chromosomal deletions and duplications. Pathogenic or possibly pathogenic microdeletions or duplications were found in 16 patients (11.4%) and further 9 with unknown significance. Two findings were in regions linked to known syndromes, two findings involved the same gene (MCC), and all other findings were unique. A closer analysis suggests a few gene networks that are involved in the pathogenesis of bladder exstrophy; the WNT-signaling pathway, the chromosome 22q11 region, the RIT2 and POU families, and involvement of the Golgi apparatus. Bladder exstrophy is a rare malformation and is reported to be associated with several chromosome aberrations. Our data suggest involvement of some specific molecular pathways.

TBX6 as a cause of a combined skeletal-kidney dysplasia syndrome

TBX6 encodes transcription-factor box 6, a transcription factor critical to paraxial mesoderm segmentation and somitogenesis during embryonic development. TBX6 haploinsufficiency is believed to drive the skeletal and kidney phenotypes associated with the 16p11.2 deletion syndrome. Heterozygous and biallelic variants in TBX6 are associated with vertebral and rib malformations (TBX6-associated congenital scoliosis) and spondylocostal dysostosis, and heterozygous TBX6 variants are associated with increased risk of genitourinary tract malformations. Combined skeletal and kidney phenotypes in individuals harboring heterozygous or biallelic TBX6 variants are rare. Here, we present seven individuals with vertebral and rib malformations and structural kidney differences associated with heterozygous TBX6 gene deletion in trans with a hypomorphic TBX6 allele or biallelic TBX6 variants. Our case series highlights the association between TBX6 and both skeletal and kidney disease.

Update on Mayer-Rokitansky-Küster-Hauser syndrome

This review presents an update of Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome on its etiologic, clinical, diagnostic, psychological, therapeutic, and reproductive aspects. The etiology of MRKH syndrome remains unclear due to its intrinsic heterogeneity. Nongenetic and genetic causes that may interact during the embryonic development have been proposed with no definitive etiopathogenesis identified. The proportion of concomitant extragenital malformations varies in different studies, and the discrepancies may be explained by ethnic differences. In addition to physical examination and pelvic ultrasound, the performance of pelvic magnetic resonance imaging is crucial in detecting the presence of rudimentary uterine endometrium. MRKH syndrome has long-lasting psychological effects on patients, resulting in low esteem, poor coping strategies, depression, and anxiety symptoms. Providing psychological counseling and peer support to diagnosed patients is recommended. Proper and timely psychological intervention could significantly improve a patient's outcome. Various nonsurgical and surgical methods have been suggested for treatment of MRKH syndrome. Due to the high success rate and minimal risk of complications, vaginal dilation has been proven to be the first-line therapy. Vaginoplasty is the second-line option for patients experiencing dilation failure. Uterine transplantation and gestational surrogacy are options for women with MRKH syndrome to achieve biological motherhood.

Gene dosage changes in KCTD13 result in penile and testicular anomalies via diminished androgen receptor function

Despite the high prevalence of hypospadias and cryptorchidism, the genetic basis for these conditions is only beginning to be understood. Using array-comparative-genomic-hybridization (aCGH), potassium-channel-tetramerization-domain-containing-13 (KCTD13) encoded at 16p11.2 was identified as a candidate gene involved in hypospadias, cryptorchidism and other genitourinary (GU) tract anomalies. Copy number variants (CNVs) at 16p11.2 are among the most common syndromic genomic variants identified to date. Many patients with CNVs at this locus exhibit GU and/or neurodevelopmental phenotypes. KCTD13 encodes a substrate-specific adapter of a BCR (BTB-CUL3-RBX1) E3-ubiquitin-protein-ligase complex (BCR (BTB-CUL3-RBX1) E3-ubiquitin-protein-ligase complex (B-cell receptor (BCR) [BTB (the BTB domain is a conserved motif involved in protein-protein interactions) Cullin3 complex RING protein Rbx1] E3-ubiqutin-protein-ligase complex), which has essential roles in the regulation of cellular cytoskeleton, migration, proliferation, and neurodevelopment; yet its role in GU development is unknown. The prevalence of KCTD13 CNVs in patients with GU anomalies (2.58%) is significantly elevated when compared with patients without GU anomalies or in the general population (0.10%). KCTD13 is robustly expressed in the developing GU tract. Loss of KCTD13 in cell lines results in significantly decreased levels of nuclear androgen receptor (AR), suggesting that loss of KCTD13 affects AR sub-cellular localization. Kctd13 haploinsufficiency and homozygous deletion in mice cause a significant increase in the incidence of cryptorchidism and micropenis. KCTD13-deficient mice exhibit testicular and penile abnormalities together with significantly reduced levels of nuclear AR and SOX9. In conclusion, gene-dosage changes of murine Kctd13 diminish nuclear AR sub-cellular localization, as well as decrease SOX9 expression levels which likely contribute in part to the abnormal GU tract development in Kctd13 mouse models and in patients with CNVs in KCTD13.

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.

Construction of Copy Number Variation Map Identifies Small Regions of Overlap and Candidate Genes for Atypical Female Genitalia Development

Copy number variations (CNVs) have been implicated in various conditions of differences of sexual development (DSD). Generally, larger genomic aberrations are more often considered disease-causing or clinically relevant, but over time, smaller CNVs have been associated with various forms of DSD. The main objective of this study is to identify small CNVs and the smallest regions of overlap (SROs) in patients with atypical female genitalia (AFG) and build a CNV map of AFG. We queried the DECIPHER database for recurrent duplications and/or deletions detected across the genome of AFG individuals. From these data, we constructed a chromosome map consisting of SROs and investigated such regions for genes that may be associated with the development of atypical female genitalia. Our study identified 180 unique SROs (7.95 kb to 45.34 Mb) distributed among 22 chromosomes. The most SROs were found in chromosomes X, 17, 11, and 22. None were found in chromosome 3. From these SROs, we identified 22 genes as potential candidates. Although none of these genes are currently associated with AFG, a literature review indicated that almost half were potentially involved in the development and/or function of the reproductive system, and only one gene was associated with a disorder that reported an individual patient with ambiguous genitalia. Our data regarding novel SROs requires further functional investigation to determine the role of the identified candidate genes in the development of atypical female genitalia, and this paper should serve as a catalyst for downstream molecular studies that may eventually affect the genetic counseling, diagnosis, and management of these DSD patients.

Endometrial organoids derived from Mayer-Rokitansky-Küster-Hauser syndrome patients provide insights into disease-causing pathways

The uterus is responsible for the nourishment and mechanical protection of the developing embryo and fetus and is an essential part in mammalian reproduction. Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome is characterized by agenesis of the uterus and upper part of the vagina in females with normal ovarian function. Although heavily studied, the cause of the disease is still enigmatic. Current research in the field of MRKH mainly focuses on DNA-sequencing efforts and, so far, has been unable to decipher the nature and heterogeneity of the disease, thereby holding back scientific and clinical progress. Here, we developed long-term expandable organoid cultures from endometrium found in uterine rudiment horns of MRKH patients. Phenotypically, they share great similarity with healthy control organoids and are surprisingly fully hormone responsive. Transcriptome analyses, however, identified an array of dysregulated genes that point to potentially disease-causing pathways altered during the development of the female reproductive tract. We consider the endometrial organoid cultures to be a powerful research tool that promise to enable an array of studies into the pathogenic origins of MRKH syndrome and possible treatment opportunities to improve patient quality of life.

Co-existing bipolar disease and 17q12 deletion: a rare case report

BACKGROUND

17q12 microdeletion syndrome is a rare autosomal dominant chromosomal anomaly, caused by the deletion of a 1.4 Mb-spanning DNA sequence on the long arm of chromosome 17. Herein, we report the first bipolar disease (BPD) case with a 1.6-Mb deletion in the 17q11.2-17q12 chromosome region.

MATERIALS AND METHODS

Physical examination of the case was performed. Karyotype and microarray analyses were performed for the case and the parents.

RESULTS

Physical examination revealed mild dysmorphic features such as high and forehead, full cheeks, slightly depressed nasal bridge and arched eyebrow. Chromosomal analysis of the patient revealed 46, XX, del(17)(q12) karyotype, and parents' karyotype were normal. In the microarray analysis of patient, 1.6 megabases deletion was detected in the 17q12 region [arr(hg19) 17q12 (34,611,352-36,248,918) ×1]. The microarray analysis of the mother was normal. The father's microarray showed 473 kilobases duplication in the 11p11.12 region.

CONCLUSION

Although 17q12 deletion syndrome has been associated with bipolar disorder, very few such cases have been described in the literature. Genetic counseling should be considered in patients with remarkable phenotype, complex symptomatology, neurodevelopmental disorder and additional conspicuous medical conditions.

Segmental Cervical Aplasia in a Colombian Creole Mare with Mosaic X-Chromosome Aneuploidy

A 4-year-old Colombian Creole mare was presented for diagnosis because the external orifice of her cervix was not detectable when a uterine lavage as therapy for uterine fluid accumulation was attempted. Clinical and ultrasonographic evaluation of the genital tract revealed that ovaries were of normal size and showed structures suggestive of regular ovarian activity. However, granular free-floating fluid material distending the uterus was detected by ultrasound. Upon vaginal examination, the normal external cervical morphology was not evident. The vagina ended in a blind bag with a small papilla with no evident external cervical os. Cytology of uterine fluid obtained by transvaginal aspiration showed findings compatible with mucometra. Cytogenetic analysis revealed an abnormal karyotype (63,X and 64,XX both 45% and 65,XXX 10%). A diagnosis of congenital segmental cervical aplasia was proposed possibly related to the mosaicism detected. To our knowledge, this is the first case of this reproductive pathology in a mare with regular ovarian activity and confirmed aneuploidy in mosaic form of the X sex chromosome.

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.

Mechanistic Drivers of Müllerian Duct Development and Differentiation Into the Oviduct

The conduits of life; the animal oviducts and human fallopian tubes are of paramount importance for reproduction in amniotes. They connect the ovary with the uterus and are essential for fertility. They provide the appropriate environment for gamete maintenance, fertilization and preimplantation embryonic development. However, serious pathologies, such as ectopic pregnancy, malignancy and severe infections, occur in the oviducts. They can have drastic effects on fertility, and some are life-threatening. Despite the crucial importance of the oviducts in life, relatively little is known about the molecular drivers underpinning the embryonic development of their precursor structures, the Müllerian ducts, and their successive differentiation and maturation. The Müllerian ducts are simple rudimentary tubes comprised of an epithelial lumen surrounded by a mesenchymal layer. They differentiate into most of the adult female reproductive tract (FRT). The earliest sign of Müllerian duct formation is the thickening of the anterior mesonephric coelomic epithelium to form a placode of two distinct progenitor cells. It is proposed that one subset of progenitor cells undergoes partial epithelial-mesenchymal transition (pEMT), differentiating into immature Müllerian luminal cells, and another subset undergoes complete EMT to become Müllerian mesenchymal cells. These cells invaginate and proliferate forming the Müllerian ducts. Subsequently, pEMT would be reversed to generate differentiated epithelial cells lining the fully formed Müllerian lumen. The anterior Müllerian epithelial cells further specialize into the oviduct epithelial subtypes. This review highlights the key established molecular and genetic determinants of the processes involved in Müllerian duct development and the differentiation of its upper segment into oviducts. Furthermore, an extensive genome-wide survey of mouse knockout lines displaying Müllerian or oviduct phenotypes was undertaken. In addition to widely established genetic determinants of Müllerian duct development, our search has identified surprising associations between loss-of-function of several genes and high-penetrance abnormalities in the Müllerian duct and/or oviducts. Remarkably, these associations have not been investigated in any detail. Finally, we discuss future directions for research on Müllerian duct development and oviducts.

Novel Technique of Vaginoplasty Developing Normal Vagina, Role of Stemness Markers and Translational Genes

Aims and Objectives:

To study development of neo-vagina by metaplastic conversion of peritoneum, To identify translational Stemness markers using NANOG/OCT4/SOX2 from serial neo-vaginal mRNA, cDNA and to study role of WNT and HOXA genes in patients undergoing vaginoplasty.

Material and Methods:

75 MRKH Syndrome women underwent laparoscopic peritoneal vaginoplasty (LPV). Two patients underwent serial neo-vaginal biopsies on day 0, 7-9, 12-14, 21 and 33. Fifteen MRKHS and twelve controls were subjected for neo-vaginal biopsy to detect genes upregulation. Remaining patients were evaluated anatomically and functionally.

Results:

The translational stemness markers NANOG, OCT4 and SOX2 responsible for neo-vaginal formation were identified. Their appearance, concentration at different stages of conversion were demonstrated. The neo-vagina has shown up-regulation of these translational stemness markers. The study demonstrates expression of the specific genes (WNT4, WNT5A and WNT7A) and their role in formation of the neo-vagina. In the subjects stemness markers (NANOG, OCT4 and SOX2) appeared from day 9 to 14 of the neo-vaginal biopsies and after achieving the peak declined later. Genetic analysis showed low values in HOXA 9,10,11,13 and up-regulation of WNT 4A,5A,7 genes in neo-vagina.

Conclusions:

Study shows peritoneal metaplastic conversion to normal vagina, identified the translational stemness markers and genes responsible. The neo-vagina has shown up-regulation of these genes. The study demonstrates expression of the specific genes (WNT4, WNT5A and WNT7A) and their role in formation of the neo-vagina. Furthering this research, activating these genes may lead to treatment of developmental defects of Mullerian duct, obviating the need of transplant.

Perturbations of genes essential for Müllerian duct and Wölffian duct development in Mayer-Rokitansky-Küster-Hauser syndrome

Mayer-Rokitansky-Küster-Hauser syndrome (MRKHS) is associated with congenital absence of the uterus, cervix, and the upper part of the vagina; it is a sex-limited trait. Disrupted development of the Müllerian ducts (MD)/Wölffian ducts (WD) through multifactorial mechanisms has been proposed to underlie MRKHS. In this study, exome sequencing (ES) was performed on a Chinese discovery cohort (442 affected subjects and 941 female control subjects) and a replication MRKHS cohort (150 affected subjects of mixed ethnicity from North America, South America, and Europe). Phenotypic follow-up of the female reproductive system was performed on an additional cohort of PAX8-associated congenital hypothyroidism (CH) (n = 5, Chinese). By analyzing 19 candidate genes essential for MD/WD development, we identified 12 likely gene-disrupting (LGD) variants in 7 genes: PAX8 (n = 4), BMP4 (n = 2), BMP7 (n = 2), TBX6 (n = 1), HOXA10 (n = 1), EMX2 (n = 1), and WNT9B (n = 1), while LGD variants in these genes were not detected in control samples (p = 1.27E-06). Interestingly, a sex-limited penetrance with paternal inheritance was observed in multiple families. One additional PAX8 LGD variant from the replication cohort and two missense variants from both cohorts were revealed to cause loss-of-function of the protein. From the PAX8-associated CH cohort, we identified one individual presenting a syndromic condition characterized by CH and MRKHS (CH-MRKHS). Our study demonstrates the comprehensive utilization of knowledge from developmental biology toward elucidating genetic perturbations, i.e., rare pathogenic alleles involving the same loci, contributing to human birth defects.

Protein-protein interaction network analysis applied to DNA copy number profiling suggests new perspectives on the aetiology of Mayer-Rokitansky-Küster-Hauser syndrome

Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome is a rare disease, characterised by the aplasia of vagina and uterus in women with a 46,XX karyotype. Most cases are sporadic, but familial recurrence has also been described. Herein, we investigated an Italian cohort of 36 unrelated MRKH patients to explore the presence of pathogenic copy number variations (CNVs) by array-CGH and MLPA assays. On the whole, aberrations were found in 9/36 (25%) patients. Interestingly, one patient showed a novel heterozygous microduplication at Xp22.33, not yet described in MRKH patients, containing the PRKX gene. Moreover, a novel duplication of a specific SHOX enhancer was highlighted by MLPA. To predict the potential significance of CNVs in MRKH pathogenesis, we provided a network analysis for protein-coding genes found in the altered genomic regions. Although not all of these genes taken individually showed a clear clinical significance, their combination in a computational network highlighted that the most relevant biological connections are related to the anatomical structure development. In conclusion, the results described in the present study identified novel genetic alterations and interactions that may be likely involved in MRKH phenotype determination, so adding new insights into the complex puzzle of MRKH disease.

The Endometrial Transcription Landscape of MRKH Syndrome

The Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome (OMIM 277000) is characterized by agenesis of the uterus and upper part of the vagina in females with normal ovarian function. While genetic causes have been identified for a small subset of patients and epigenetic mechanisms presumably contribute to the pathogenic unfolding, too, the etiology of the syndrome has remained largely enigmatic. A comprehensive understanding of gene activity in the context of the disease is crucial to identify etiological components and their potential interplay. So far, this understanding is lacking, primarily due to the scarcity of samples and suitable tissue. In order to close this gap, we profiled endometrial tissue of uterus rudiments in a large cohort of MRKH patients using RNA-seq and thereby provide a genome-wide view on the altered transcription landscape of the MRKH syndrome. Differential and co-expression analyses of the data identified cellular processes and candidate genes that converge on a core network of interconnected regulators that emerge as pivotal for the perturbed expression space. With these results and browsable access to the rich data through an online tool we seek to accelerate research to unravel the underlying biology of the syndrome.

Whole-exome sequencing identifies a GREB1L variant in a three-generation family with Müllerian and renal agenesis: a novel candidate gene in Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome. A case report

The aetiology of Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome, characterized by uterovaginal agenesis in 46,XX women, remains poorly understood. Since familial occurrences are rare, genetic findings reported so far only apply to a minority of mainly sporadic cases and most studies have not included other family members enabling segregation analysis. Herein, we report on the investigation of a unique three-generation family of two female cousins with MRKH syndrome and unilateral renal agenesis (RA) and two deceased male relatives with RA. We performed whole-exome sequencing (WES) in eight family members leading to the identification of a novel pathogenic (CADD = 33) c.705G>T missense variant in GREB1L, a gene recently identified as a novel cause of RA. Previous reports include several cases of female fetuses with bilateral RA and uterus agenesis, which support GREB1L as an important gene in both kidney and female genital tract development. The pedigree is compatible with autosomal dominant inheritance with incomplete penetrance following a parent-origin-specific manner, which could be due to imprinting. To our knowledge, this is the first investigation of a larger MRKH syndrome pedigree using WES, and we suggest GREB1L as a novel and promising candidate gene in the aetiology of MRKH syndrome.

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.

GREB1L variants in familial and sporadic hereditary urogenital adysplasia and Mayer-Rokitansky-Kuster-Hauser syndrome

Congenital uterine anomalies (CUA) may have major impacts on the health and social well-being of affected individuals. Their expressivity is variable, with the most severe end of the spectrum being the absence of any fully or unilaterally developed uterus (aplastic uterus), which is a major feature in Mayer-Rokitansky-Kuster-Hauser syndrome (MRKH). So far, etiologies of CUA remain largely unknown. As reports of familial occurrences argue for strong genetic contributors in some cases, we performed whole exome sequencing in nine multiplex families with recurrence of uterine and kidney malformations, a condition called hereditary urogenital adysplasia. Heterozygous likely causative variants in the gene GREB1L were identified in four of these families, confirming GREB1L as an important gene for proper uterine and kidney development. The apparent mode of inheritance was autosomal dominant with incomplete penetrance. The four families included fetuses with uterovaginal aplasia and bilateral renal agenesis, highlighting the importance to investigate GREB1L in such phenotypes. Subsequent sequencing of the gene in a cohort of 68 individuals with MRKH syndrome or uterine malformation (mostly sporadic cases) identified six additional variants of unknown significance. We therefore conclude that heterozygous GREB1L variants contribute to MRKH syndrome and this probably requires additional genetic or environmental factors for full penetrance.

Sequence variant in the CDC42BPB gene is potentially associated with Mullerian duct anomalies

AIM

Mullerian duct anomalies (MDA) are common female genital tract malformations. Genetic and environmental factors are important causes of MDA in women. Although many genes and mutations have been found to be associated with the pathogenesis of MDA, in most cases, the genetic pathogenic factors of MDA are still unknown.

METHODS

We first analyzed the three sisters using low coverage whole-genome sequencing. Then whole-exome sequencing was carried out in each patient. The identified sequence variant was confirmed by Sanger sequencing. In silico pathogenicity analysis and conservative analysis of the mutation site were also performed. Protein structural modeling was used to analyze the effect of the mutated amino acid.

RESULTS

We first analyzed the three sisters with septate uterus using low coverage whole-genome sequencing, but no possible pathogenic copy number variation was found. Then whole-exome sequencing was performed on the three sisters, and a rare homozygous variant, CDC42BPB:c.2012G>A:p.R671Q, was identified. All three patients were found with this variant. Sanger sequencing validated that this variant was segregated within the family. In silico pathogenicity analysis and conservative analysis of the mutation site suggested that the variant might be damaging. Protein structural analysis suggested that R671Q might weaken the electrostatic potential of this region, which may be a significant regulation target or protein interaction surface of CDC42BPB.

CONCLUSION

We demonstrated that CDC42BPB genetic variant might be potentially associated with the pathogenesis of MDA.

Whole-Exome Sequencing Identified a TBX6 Loss of Function Mutation in a Patient with Distal Vaginal Atresia

STUDY OBJECTIVE

The purpose of this study was to determine if there are any genetic changes with whole-exome sequencing associated with distal vaginal atresia.

DESIGN

This was a retrospective genetics study of 5 patients who presented with distal vaginal atresia who were recruited between 2017 and 2018. Whole-exome sequencing was performed in each subject with distal vaginal atresia. Sanger sequencing was used to confirm the potential causative genetic mutation.

SETTING

Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing, China.

PARTICIPANTS AND MAIN OUTCOME MEASURES

The main outcome measure was the rare mutations potentially associated with distal vaginal atresia in 5 patients.

RESULTS

A truncating mutation c.266delC (p.P89Rfs*5) in the T-box transcription factor 6 (TBX6) gene, which is highly expressed in the human vagina, was identified in 1 patient using whole-exome sequencing. The deletion of the 16p11.2 region containing the TBX6 locus has also been reported previously to have the clinical feature of Müllerian agenesis. This mutation was paternally inherited by the patient. This truncating mutation was absent from all of the databases we checked, suggesting that the variant is rare and pathogenic.

CONCLUSION

We showed, to our knowledge, for the first time, that the mutation in TBX6 might be associated with human distal vaginal atresia.

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.

Single-cell sequencing of neonatal uterus reveals an Misr2+ endometrial progenitor indispensable for fertility

The Mullerian ducts are the anlagen of the female reproductive tract, which regress in the male fetus in response to MIS. This process is driven by subluminal mesenchymal cells expressing Misr2, which trigger the regression of the adjacent Mullerian ductal epithelium. In females, these Misr2+ cells are retained, yet their contribution to the development of the uterus remains unknown. Here, we report that subluminal Misr2+ cells persist postnatally in the uterus of rodents, but recede by week 37 of gestation in humans. Using single-cell RNA sequencing, we demonstrate that ectopic postnatal MIS administration inhibits these cells and prevents the formation of endometrial stroma in rodents, suggesting a progenitor function. Exposure to MIS during the first six days of life, by inhibiting specification of the stroma, dysregulates paracrine signals necessary for uterine development, eventually resulting in apoptosis of the Misr2+ cells, uterine hypoplasia, and complete infertility in the adult female.

In the womb, mammals possess all of the preliminary sexual structures necessary to become either male or female. This includes the Mullerian duct, which develops into the Fallopian tubes, uterus, cervix, and vagina in female fetuses. In male fetuses, the testis secretes a hormone called Mullerian inhibiting substance (MIS). This triggers the activity of a small group of cells, known as Misr2+ cells, that cause the Mullerian duct to degenerate, preventing males from developing female sexual organs.

It was not clear what happens to Misr2+ cells in female fetuses or if they affect how the uterus develops. Saatcioglu et al. now show that in newborn female mice and rats, a type of Misr2+ cell that sits within a thin inner layer of the developing uterus still responds to MIS. At this time, the uterus is in a critical early period of development. Treating the mice and rats with MIS protein during their first six days of life eventually caused the Misr2+ cells to die. The treatment also prevented a layer of connective tissue, known as the endometrial stroma, from forming in the uterus. As a result, the mice and rats were infertile and had severely underdeveloped uteri.

While the Misr2+ cells are present in newborn rats and mice, Saatcioglu et al. found that they disappeared before birth in humans. However, the overall results suggest that Misr2+ cells act as progenitor cells that develop into the cells of the endometrial stroma. Future work could investigate the roles these cells play in causing uterine developmental disorders and infertility disorders. Furthermore, the finding that MIS inhibits the Misr2+ cells could help researchers to develop treatments for uterine cancer and other conditions where the cells of the uterus grow and divide too much.

Identification of Candidate Genes for Mayer-Rokitansky-Küster-Hauser Syndrome Using Genomic Approaches

Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome is a disorder of sex development which affects 1 in 4,500 females and is characterized by agenesis of müllerian structures, including the uterus, cervix, and upper vagina. It can occur in isolation (type 1) or in conjunction with various anomalies (type 2), with a subset of these comprising müllerian, renal, and cervicothoracic abnormalities (MURCS) association. The genetic causes of MRKH have been investigated previously yielding limited results, with massive parallel sequencing becoming increasingly utilized. We sought to identify genetic contributions to MRKH using a combination of microarray and whole exome sequencing (WES) on a cohort of 8 unrelated women with MRKH and MURCS. WES data were analysed using a candidate gene approach to identify potential contributing variants. Microarray analysis identified a 0.6-Mb deletion in the previously implicated 16p11.2 region in a patient with MRKH type 2. WES revealed 16 rare nonsynonymous variants in MRKH candidate genes across the cohort. These included variants in several genes, such as LRP10 and DOCK4, associated with disorders with müllerian anomalies. Further functional studies of these variants will help to delineate their biological significance and expand the genotypic spectrum of MRKH.

Mayer-Rokitansky-Küster-Hauser Syndrome and 16p11.2 Recurrent Microdeletion: A Case Report and Review of the Literature

BACKGROUND

Mayer-Rokitansky-Küster-Hauser syndrome (MRKH; Online Mendelian Inheritance in Man #277000) is a rare disorder of the female reproductive tract. Its etiology is still unknown for most patients, although the genetic background of this condition has been intensively studied. Chromosome 16p11.2 deletion syndrome (Online Mendelian Inheritance in Man #611913) is a well known recurrent deletion syndrome that can present with various clinical phenotypes, including developmental delay, intellectual disability, autism spectrum disorder, obesity, and an increased frequency of congenital defects.

CASE

Herein we report a patient with 16p11.2 recurrent microdeletion in whom MRKH syndrome was diagnosed in adolescence.

SUMMARY AND CONCLUSION

Our purpose is to underscore the possible presence of gynecological malformations in patients with 16p11.2 microdeletion and highlight the utility of a genetic evaluation in cases of MRKH syndrome.

17q12 Deletion Syndrome as a Rare Cause for Diabetes Mellitus Type MODY5

CONTEXT

Maturity-onset diabetes of the young type 5 (MODY5) is caused by mutations of the hepatocyte nuclear factor 1 homeobox β gene (HNF1B). Although clinical characteristics and therapeutic management of MODY5 are increasingly better defined, adequate consideration of the frequent association of MODY5 with 17q12 deletion syndrome is often missing.

EVIDENCE ACQUISITION

We report two cases of patients with 17q12 deletion syndrome who presented to our clinic. Furthermore, we reviewed the existing literature to improve systematic diagnostic and therapeutic approaches. A PubMed search using the terms 17q12 deletion syndrome, diabetes mellitus type MODY5, and/or HNF1B was performed.

EVIDENCE SYNTHESIS

Three hundred sixty-one cases of postnatal 17q12 deletion syndrome were assessed, and details on clinical manifestations, diagnostic approaches, and therapeutic management were reviewed and compared with the two cases at our clinic. Furthermore, data on pathogenic mechanisms and their clinical implications were evaluated.

CONCLUSION

The 17q12 deletion syndrome usually comprises MODY5, structural or functional abnormalities of the kidneys, and neurodevelopmental or neuropsychiatric disorders. A complete deletion of HNF1B can be found in about 50% of patients with MODY5. A wide variety of additional clinical features, including genital and brain malformations, has been reported. Because HNF1B deletions are virtually always part of a 17q12 deletion syndrome and common genetic analyses for evaluation of MODY5 are unable to detect the deletion of a 1.4-Mb chromosomal region, initial attention to the syndromal features at the stage of diagnosis is of considerable importance for establishing correct diagnosis, subsequent therapy, and interdisciplinary patient care.

Müllerian Agenesis in Cat Eye Syndrome and 22q11 Chromosome Abnormalities: A Case Report and Literature Review

BACKGROUND

Although Müllerian agenesis is the second most common cause of primary amenorrhea the underlying etiology in most cases is unknown. Müllerian agenesis has been reported as a rare finding associated with chromosomal aberrations of the 22q11 chromosomal region including at least 1 individual with cat eye syndrome (CES) and 10 individuals with deletions or duplications of the 22q11.2 region. However, a potential link between 22q11 abnormalities and uterine malformations has been difficult to adequately ascertain because of the limited case reports in the literature.

CASE

We report a second case of Müllerian agenesis in a girl with CES. A 16-year-old girl presented with bilateral colobomata, primary amenorrhea, and absence of the uterus and upper vagina on pelvic magnetic resonance imaging. Microarray analysis showed tetrasomy of the pericentromeric region of chromosome 22 diagnostic of CES.

SUMMARY AND CONCLUSION

Müllerian aplasia/hypoplasia might represent a rare feature in CES and should be considered in the investigation of young girls with this syndrome. An increasing number of cases with 22q11 chromosome abnormalities and Müllerian agenesis further highlights the possibility of a gene within the 22q11 region that might mediate normal Müllerian development in girls.

Clinical and genetic aspects of Mayer-Rokitansky-Küster-Hauser syndrome

The Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome [MIM 277000] is characterised by the absence of a uterus and vagina in otherwise phenotypically normal women with karyotype 46,XX. Clinically, the MRKH can be subdivided into two subtypes: an isolated or type I form can be delineated from a type II form, which is characterised by extragenital malformations. The so-called Müllerian hypoplasia, renal agenesis, cervicothoracic somite dysplasia (MURCS) association can be seen as the most severe phenotypic outcome. The MRKH syndrome affects at least 1 in 4000 to 5000 female new-borns. Although most of the cases are sporadic, familial clustering has also been described, indicating a genetic cause of the disease. However, the mode of inheritance is autosomal-dominant inheritance with reduced penetrance. High-resolution array-CGH and MLPA analysis revealed recurrent aberrations in different chromosomal regions such as TAR susceptibility locus in 1q21.1, chromosomal regions 16p11.2, and 17q12 and 22q11.21 microduplication and -deletion regions in patients with MRKH. Sequential analysis of the genes LHX1, TBX6 and RBM8A, which are located in chromosomal regions 17q12, 16p11.2 and 1q21.1, yielded in the detection of MRKH-associated mutations. In a subgroup of patients with signs of hyperandrogenaemia mutations of WNT4 have been found to be causative. Analysis of another member of the WNT family, WNT9B, resulted in the detection of some causative mutations in MRKH patients.

Identification and functional analysis of a novel LHX1 mutation associated with congenital absence of the uterus and vagina

Congenital absence of the uterus and vagina (CAUV) is the most extreme female Müllerian duct abnormality. Several researches proposed that genetic factors contributed to this disorder, whereas the precise genetic mechanism is far from full elucidation. Here, utilizing whole-exome sequencing (WES), we identified one novel missense mutation in LHX1 (NM_005568: c.G1108A, p.A370T) in one of ten unrelated patients diagnosed with CAUV. This mutation was absent from public databases and our internal database. Through the luciferase reporter analysis, we found that the mutation could change the transcriptional activity of LHX1 and its effect on the regulation of the downstream target gene GSC, which might be associated with urogenital system development. In short, we concluded that the LHX1 may be a pathogenic gene of CAUV. Our results demonstrate the power of whole exome sequencing and gene prioritization approach as diagnostic tools in clinical practice that help make genetic diagnosis of CAUV.

16p11.2 transcription factor MAZ is a dosage-sensitive regulator of genitourinary development

Genitourinary (GU) birth defects are among the most common yet least studied congenital malformations. Congenital anomalies of the kidney and urinary tract (CAKUTs) have high morbidity and mortality rates and account for ∼30% of structural birth defects. Copy number variation (CNV) mapping revealed that 16p11.2 is a hotspot for GU development. The only gene covered collectively by all of the mapped GU-patient CNVs was MYC-associated zinc finger transcription factor (MAZ), and MAZ CNV frequency is enriched in nonsyndromic GU-abnormal patients. Knockdown of MAZ in HEK293 cells results in differential expression of several WNT morphogens required for normal GU development, including Wnt11 and Wnt4. MAZ knockdown also prevents efficient transition into S phase, affects transcription of cell-cycle regulators, and abrogates growth of human embryonic kidney cells. Murine Maz is ubiquitously expressed, and a CRISPR-Cas9 mouse model of Maz deletion results in perinatal lethality with survival rates dependent on Maz copy number. Homozygous loss of Maz results in high penetrance of CAKUTs, and Maz is haploinsufficient for normal bladder development. MAZ, once thought to be a simple housekeeping gene, encodes a dosage-sensitive transcription factor that regulates urogenital development and contributes to both nonsyndromic congenital malformations of the GU tract as well as the 16p11.2 phenotype.

Copy number variation and regions of homozygosity analysis in patients with MÜLLERIAN aplasia

BACKGROUND

Little is known about the genetic contribution to Müllerian aplasia, better known to patients as Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome. Mutations in two genes (WNT4 and HNF1B) account for a small number of patients, but heterozygous copy number variants (CNVs) have been described. However, the significance of these CNVs in the pathogenesis of MRKH is unknown, but suggests possible autosomal dominant inheritance. We are not aware of CNV studies in consanguineous patients, which could pinpoint genes important in autosomal recessive MRKH. We therefore utilized SNP/CGH microarrays to identify CNVs and define regions of homozygosity (ROH) in Anatolian Turkish MRKH patients.

RESULTS

Five different CNVs were detected in 4/19 patients (21%), one of which is a previously reported 16p11.2 deletion containing 32 genes, while four involved smaller regions each containing only one gene. Fourteen of 19 (74%) of patients had parents that were third degree relatives or closer. There were 42 regions of homozygosity shared by at least two MRKH patients which was spread throughout most chromosomes. Of interest, eight candidate genes suggested by human or animal studies (RBM8A, CMTM7, CCR4, TRIM71, CNOT10, TP63, EMX2, and CFTR) reside within these ROH.

CONCLUSIONS

CNVs were found in about 20% of Turkish MRKH patients, and as in other studies, proof of causation is lacking. The 16p11.2 deletion seen in mixed populations is also identified in Turkish MRKH patients. Turkish MRKH patients have a higher likelihood of being consanguineous than the general Anatolian Turkish population. Although identified single gene mutations and heterozygous CNVs suggest autosomal dominant inheritance for MRKH in much of the western world, regions of homozygosity, which could contain shared mutant alleles, make it more likely that autosomal recessively inherited causes will be manifested in Turkish women with MRKH.

Hyperandrogenemia and ovarian reserve in patients with Mayer-Rokitansky-Küster-Hauser syndrome type 1 and 2: potential influences on ovarian stimulation

PURPOSE

This study aimed to analyze the hormone profiles, to detect the rate of hyperandrogenemia and to investigate the potential effect of Mayer-Rokitansky-Küster-Hauser syndrome (MRKHS) on ovarian reserve, as reflected by the serum Anti-Mullerian hormone (AMH) levels. Clinical implications were analyzed by including our own experiences with three patients after ovarian stimulation in preparation for uterus transplantation.

METHODS

Serum samples of 100 patients with MRKHS (50 patients with MRKHS type 1 and 50 with type 2) were analyzed and compared to 50 individually age-matched healthy controls. Blood samples for hormone analyses were collected routinely during the clinical visit.

RESULTS

The mean age was 20.0 years for MRKHS type 1, MRKHS type 2 and healthy controls. Compared to healthy controls, there was no significant difference in AMH values in the MRKH patients. As shown in previous studies, the proportion of hyperandrogenemia without clinical symptoms was significantly higher in MRKHS type 1 (52%; p < 0.001) and type 2 (56%; p < 0.001) patients when compared to age-matched controls. In preparation for uterus transplantation, three patients were stimulated with FSH/hMG for mean 14.2 days and the mean number of aspirated oocytes was 13.2 (3-22), while 8.3 (2-10) oocytes could be fertilized and cryopreserved. The mean fertilization rate was 51.2% (30-67%).

CONCLUSION

The rate of hyperandrogenemia was significantly higher in MRKH patients compared to healthy age-matched controls. Though, ovarian reserve (AMH level) was not reduced compared to controls. Future studies are needed to identify optimal ovarian stimulation protocols as well as to implement a systematic multicenter reporting system.

Genetics of gynaecological disorders

From genomic imbalances associated with developmental abnormalities of the female genital tract to the molecular mechanisms underpinning endometriosis and uterine leiomyomatosis, new technologies have allowed the exploration of the genetic contribution and mapping the molecular pathways underpinning common and rare gynaecological conditions. While some of these conditions have historically been considered sporadic, recent research has demonstrated their potentially heritable nature linked to single genes or copy number variants. The phenotypic variability including non-penetrance indicates their multifactorial, complex aetiology encompassing genetic, epigenetic and environmental influences. Although genetic tests are not routinely conducted in gynaecological practice, there is an increasing body of evidence suggesting that, in appropriate cases, molecular investigations such as array CGH analysis may be an important part of the diagnostic algorithm. The subtlety of clinical features, especially in the context of syndromic diagnoses, requires the practitioner to become familiar with those conditions and the approach to diagnostic investigations. This chapter combines the recent research output related to gynaecological disorders with a clinical genetics approach aiming to highlight the multisystem character of some of these conditions, their implications for management, reproductive risks and options, and the importance of genetic counselling.

Genetic analysis of Mayer-Rokitansky-Kuster-Hauser syndrome in a large cohort of families

OBJECTIVE

To study the genetic cause of Mayer-Rokitansky-Kuster-Hauser syndrome (MRKH). Although a few candidate genes and genomic domains for have been reported for MRKH, the genetic underpinnings remain largely unknown. Some of the top candidate genes are WNT4, HNF1B, and LHX1. The goals of this study were to: 1) determine the prevalence of WNT4, HNF1B, and LHX1 point mutations, as well as new copy number variants (CNVs) in people with MRKH; and 2) identify and characterize MRKH cohorts.

DESIGN

Laboratory- and community-based study.

SETTING

Academic medical centers.

PATIENT(S)

A total of 147 MRKH probands and available family members.

INTERVENTIONS(S)

DNA sequencing of WNT4, HNF1B, and LHX1 in 100 MRKH patients, chromosomal microarray analysis in 31 North American MRKH patients, and characterization and sample collection of 147 North American and Turkish MRKH probands and their families.

MAIN OUTCOME MEASURE(S)

DNA sequence variants and CNVs; pedigree structural analysis.

RESULT(S)

We report finding CNVs in 6/31 people (∼19%) with MRKH, but no point mutations or small indels in WNT4, HNF1B, or LHX1 in 100 MRKH patients. Our MRKH families included 43 quads, 26 trios, and 30 duos. Of our MRKH probands, 87/147 (59%) had MRKH type 1 and 60/147 (41%) had type 2 with additional anomalies.

CONCLUSION(S)

Although the prevalence of WNT4, HNF1B, and LHX1 point mutations is low in people with MRKH, the prevalence of CNVs was ∼19%. Further analysis of our large familial cohort of patients will facilitate gene discovery to better understand the complex etiology of MRKH.

Vertebral defect, anal atresia, cardiac defect, tracheoesophageal fistula/esophageal atresia, renal defect, and limb defect association with Mayer-Rokitansky-Küster-Hauser syndrome in co-occurrence: two case reports and a review of the literature

BACKGROUND

The vertebral defect, anal atresia, cardiac defect, tracheoesophageal fistula/esophageal atresia, renal defect, and limb defect association and Mayer-Rokitansky-Küster-Hauser syndrome are rare conditions. We aimed to present two cases with the vertebral defect, anal atresia, cardiac defect, tracheoesophageal fistula/esophageal atresia, renal defect, and limb defect association and Mayer-Rokitansky-Küster-Hauser co-occurrence from our local surgical center and through a systematic literature search detect published cases. Furthermore, we aimed to collect existing knowledge in the embryopathogenesis and genetics in order to discuss a possible link between the vertebral defect, anal atresia, cardiac defect, tracheoesophageal fistula/esophageal atresia, renal defect, and limb defect association and Mayer-Rokitansky-Küster-Hauser syndrome.

CASE PRESENTATION

Our first case was a white girl delivered by caesarean section at 37 weeks of gestation; our second case was a white girl born at a gestational age of 40 weeks. A co-occurrence of vertebral defect, anal atresia, cardiac defect, tracheoesophageal fistula/esophageal atresia, renal defect, and limb defect association and Mayer-Rokitansky-Küster-Hauser syndrome was diagnosed in both cases. We performed a systematic literature search in PubMed ((VACTERL) OR (VATER)) AND ((MRKH) OR (Mayer-Rokitansky-Küster-Hauser) OR (mullerian agenesis) OR (mullerian aplasia) OR (MURCS)) without limitations. A similar search was performed in Embase and the Cochrane library. We added two cases from our local center. All cases (n = 9) presented with anal atresia and renal defect. Vertebral defects were present in eight patients. Rectovestibular fistula was confirmed in seven patients. Along with the uterovaginal agenesis, fallopian tube aplasia appeared in five of nine cases and in two cases ovarian involvement also existed.

CONCLUSIONS

The co-occurrence of the vertebral defect, anal atresia, cardiac defect, tracheoesophageal fistula/esophageal atresia, renal defect, and limb defect association and Mayer-Rokitansky-Küster-Hauser syndrome is extremely rare. This group of patients has unusual phenotypic characteristics. The long-term outcome after treatment of defects is not well reported. A single unifying cause is not known and the etiology probably includes both genetic and non-genetic causes. We stress the importance of future studies to optimized treatment, follow-up, and etiology.