Etiologies of uterine malformations

OSR1 disruption contributes to uterine factor infertility via impaired Müllerian duct development and endometrial receptivity

Three sisters, born from consanguineous parents, manifested a unique Müllerian anomaly characterized by uterine hypoplasia with thin estrogen-unresponsive endometrium and primary amenorrhea, but with spontaneous tubal pregnancies. Through whole-exome sequencing followed by comprehensive genetic analysis, a missense variant was identified in the OSR1 gene. We therefore investigated OSR1/OSR1 expression in postpubertal human uteri, and the prenatal and postnatal expression pattern of Osr1/Osr1 in murine developing Müllerian ducts (MDs) and endometrium, respectively. We then investigated whether Osr1 deletion would affect MD development, using WT and genetically engineered mice. Human uterine OSR1/OSR1 expression was found primarily in the endometrium. Mouse Osr1 was expressed prenatally in MDs and Wolffian ducts (WDs), from rostral to caudal segments, in E13.5 embryos. MDs and WDs were absent on the left side and MDs were rostrally truncated on the right side of E13.5 Osr1-/- embryos. Postnatally, Osr1 was expressed in mouse uteri throughout their lifespan, peaking at postnatal days 14 and 28. Osr1 protein was present primarily in uterine luminal and glandular epithelial cells and in the epithelial cells of mouse oviducts. Through this translational approach, we demonstrated that OSR1 in humans and mice is important for MD development and endometrial receptivity and may be implicated in uterine factor infertility.

Rare variant enrichment analysis supports GREB1L as a contributory driver gene in the etiology of Mayer-Rokitansky-Küster-Hauser syndrome

Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome is characterized by aplasia of the female reproductive tract; the syndrome can include renal anomalies, absence or dysgenesis, and skeletal anomalies. While functional models have elucidated several candidate genes, only WNT4 (MIM: 603490) variants have been definitively associated with a subtype of MRKH with hyperandrogenism (MIM: 158330). DNA from 148 clinically diagnosed MRKH probands across 144 unrelated families and available family members from North America, Europe, and South America were exome sequenced (ES) and by family-based genomics analyzed for rare likely deleterious variants. A replication cohort consisting of 442 Han Chinese individuals with MRKH was used to further reproduce GREB1L findings in diverse genetic backgrounds. Proband and OMIM phenotypes annotated using the Human Phenotype Ontology were analyzed to quantitatively delineate the phenotypic spectrum associated with GREB1L variant alleles found in our MRKH cohort and those previously published. This study reports 18 novel GREB1L variant alleles, 16 within a multiethnic MRKH cohort and two within a congenital scoliosis cohort. Cohort-wide analyses for a burden of rare variants within a single gene identified likely damaging variants in GREB1L (MIM: 617782), a known disease gene for renal hypoplasia and uterine abnormalities (MIM: 617805), in 16 of 590 MRKH probands. GREB1L variant alleles, including a CNV null allele, were found in 8 MRKH type 1 probands and 8 MRKH type II probands. This study used quantitative phenotypic analyses in a worldwide multiethnic cohort to identify and strengthen the association of GREB1L to isolated uterine agenesis (MRKH type I) and syndromic MRKH type II.

Can Classifications Adequately Represent Genital Malformations?: EVA Study ( E SHRE/ESGE | V CUAM | A FS) - A Prospective Multicenter Study to Evaluate the Current Female Genital Malformation Classifications

Introduction Genital malformations are a common clinical occurrence that can be represented using different classifications. Reproducibility is an essential quality characteristic for a classification, and it plays an important role, especially in consultations and the treatment of infertile patients and in obstetric management. The aim of this study is to demonstrate the reproducibility and clinical practicality of three commonly used classifications: the ESHRE/ESGE (European Society of Human Reproduction and Embryology/ European Society for Gynecological Endoscopy), VCUAM (Vagina Cervix Uterus Adnex-associated Malformation), and AFS (American Fertility Society) classifications. Materials and Methods Sixty-five patients with female genital malformations were included in this prospective, multicenter, exploratory, observational study. All participants underwent a clinical examination and a medical interview. The investigators were instructed to classify the presenting malformations according to the ESHRE/ESGE, VCUAM, and AFS classifications using a structured questionnaire. Investigators were asked whether the malformation could be reproducibly classified (yes/no) and about the grade (grade 1-5 from "very good" to "deficient") they would assign to each classification. Classification assessment was queried for vagina, cervix, uterus, adnexa, and associated malformations and was scored from 1 to 5. Results Reproducibility was rated as 80% (n = 52/65), 92.3% (n = 60/65), and 56.9% (n = 37/65) for the ESHRE/ESGE, VCUAM, and AFS classification, respectively. ESHRE/ESGE, VCUAM and AFS were rated as "very good" or "good" for 83.3%, 89.2%, and 10.8% of vaginal malformations; for 75.8%, 87.5%, and 24.2% of cervical malformations; and for 89.7%, 89.5%, and 86.2% of uterine malformations, respectively. VCUAM was rated as "very good" or "good" for 77.8% and 69.6% of adnexal malformations and associated malformations, respectively. ESHRE/ESGE and AFS were rated as "sufficient" or "deficient" for 100% and 75% of adnexal malformations and for 77.3% and 69.6% of associated malformations, respectively. Conclusion The prospective multicenter EVA ( E SHRE/ESGE | V CUAM | A FS) study revealed that the organ-based ESHRE/ESGE and VCUAM classifications of female genital malformations perform better in terms of reproducibility as well as in the assessment of individual compartments than the non-organ-based AFS classification.

Uterus infantilis: a novel phenotype associated with AARS2 new genetic variants. A case report

Objectives

To report the first Mexican case with two novel AARS2 mutations causing primary ovarian failure, uterus infantilis, and early-onset dementia secondary to leukoencephalopathy.

Methods

Detailed clinical, clinimetric, neuroimaging features, muscle biopsy with biochemical assays of the main oxidative phosphorylation complexes activities, and molecular studies were performed on samples from a Mexican female.

Results

We present a 41-year-old female patient with learning difficulties since childhood and primary amenorrhea who developed severe cognitive, motor, and behavioral impairment in early adulthood. Neuroimaging studies revealed frontal leukoencephalopathy with hypometabolism at the fronto-cerebellar cortex and caudate nucleus. Uterus infantilis was detected on ultrasound study. Clinical exome sequencing identified two novel variants, NM_020745:c.2864G>A (p.W955^*) and NM_020745:c.1036C>A (p.P346T, p.P346Wfs^*18), in AARS2. Histopathological and biochemical studies on muscle biopsy revealed mitochondrial disorder with cytochrome C oxidase (COX) deficiency.

Conclusions

Several adult-onset cases of leukoencephalopathy and ovarian failure associated with AARS2 variants have been reported. To our best knowledge, none of them showed uterus infantilis. Here we enlarge the genetic and phenotypic spectrum of AARS2-related dementia with leukoencephalopathy and ovarian failure and contribute with detailed clinical, clinometric, neuroimaging, and molecular studies to disease and novel molecular variants characterization.

Septum Resection Prior to In Vitro Fertilization-Embryo Transfer: A Retrospective Controlled Study

OBJECTIVES

To investigate the effectiveness of surgery for septate uterus in infertile patients before in vitro fertilization-embryo transfer (IVF-ET).

METHODS

The data of 937 infertile patients with septate uterus and achieved singleton pregnancy after IVF-ET from January 2014 to December 2015 were retrospectively analyzed. Thousand five hundred seventy-eight infertile patients with a normal uterus who achieved singleton pregnancy during the same period were selected as the control group. Patients with septate uterus were divided into two groups according to whether the septum was resected. The pregnancy and perinatal outcomes of the surgical group and the nonsurgical group were compared with the control group. The secondary infertility patients who were surgically corrected septa were also chosen as self-controls and an analysis was performed on their fertility outcomes pre- and post-surgery.

RESULTS

Compared with the control group, the surgical group had increased rates of early miscarriage, preterm delivery, and low birthweight and a significantly reduced live birth rate (P < .05). The outcomes of the nonsurgical and control groups were similar. Using secondary infertility patients who were surgically corrected septa as self-controls, after surgery, the rates of miscarriage and ectopic pregnancy were significantly lower and the live birth rate was significantly higher (P ≤ .001); however, perinatal mortality was not significantly different before and after surgery.

CONCLUSIONS

Patients with a septum depth greater than 10 mm or 5-10 mm associated with a history of unexplained recurrent miscarriage, IVF failure, or infertility might benefit from resection of the uterine septum with hysteroscopic metroplasty.

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.

Diagnostic and Management of Undescended Ovary - A Preoperative Dilemma: A Case-Based Systematic Review

Undescended ovary (UO) is an uncommon congenital condition characterized by the presence of the adnexa above the common iliac vessels, with an estimated incidence of 0.3–2%. Because of its rarity, it is usually presented as a case report. A thorough knowledge of the ovarian embryological development is essential for the clinician, who must be warned about the possibility of associated Müllerian and renal malformations. There may be asymptomatic patients, incidentally diagnosed during infertility evaluation, but when symptoms occur, these are unspecific and most often this disorder is misdiagnosed, the accurate diagnosis being established intraoperatory. The malignant potential of an UO is accepted, although no such cases were reported. The role of the UO in infertility is still unclear, despite evidence of its normal function. Complications are linked to the ovary (cyst formation, cyst ruptures or tumors) or to the undescended fallopian tube (ectopic pregnancies). The management should be conservative, but there is no consensus about whether it is necessary to excise the ipsilateral undescended tube. We included a short case presentation of an UO cystadenoma misdiagnosed as a renal cyst, which depicts all diagnostic and management dilemmas and inspired us to write this review. The present literature review includes all the cases reported from the early 20th century to the present, with updated data about epidemiology, pathophysiology, clinical and imaging diagnosis, treatment options and prognosis of this rare condition. This paper aims to establish some directions in the diagnosis and management of similar patients and to remind us that, no matter how advanced the imaging investigation techniques might be, a correct preoperative diagnosis may often be missed.

Society for Endocrinology UK Guidance on the initial evaluation of a suspected difference or disorder of sex development (Revised 2021)

It is paramount that any child or adolescent with a suspected difference or disorder of sex development (DSD) is assessed by an experienced clinician with adequate knowledge about the range of conditions associated with DSD and is discussed with the regional DSD service. In most cases, the paediatric endocrinologist within this service acts as the first point of contact but involvement of the regional multidisciplinary service will also ensure prompt access to specialist psychology and nursing care. The underlying pathophysiology of DSD and the process of delineating this should be discussed with the parents and affected young person with all diagnostic tests undertaken in a timely fashion. Finally, for rare conditions such as these, it is imperative that clinical experience is shared through national and international clinical and research collaborations.

Primary Amenorrhea Due to Anatomical Abnormalities of the Reproductive Tract: Molecular Insight

Congenital anomalies of the female reproductive tract that present with primary amenorrhea involve Müllerian aplasia, also known as Mayer-Rokitansky-Küster-Hauser syndrome (MRKHS), and cervical and vaginal anomalies that completely obstruct the reproductive tract. Karyotype abnormalities do not exclude the diagnosis of MRKHS. Familial cases of Müllerian anomalies and associated malformations of the urinary and skeletal systems strongly suggest a complex genetic etiology, but so far, the molecular mechanism in the vast majority of cases remains unknown. Primary amenorrhea may also be the first presentation of complete androgen insensitivity syndrome, steroid 5α-reductase type 2 deficiency, 17β-hydroxysteroid dehydrogenase type 3 deficiency, and Leydig cells hypoplasia type 1; therefore, these disorders should be considered in the differential diagnosis of the congenital absence of the uterus and vagina. The molecular diagnosis in the majority of these cases can be established.

Oblique Cervical Septum with Complete Uterine Septum: Diagnosis and Treatment of a Rare Case

BACKGROUND

Müllerian anomalies take many forms of manifestation. The oblique cervical septum with a complete uterine septum (OCSCUS), as a rare form of Müllerian anomaly, has never been reported in the literature.

CASE

A 10-year-old female adolescent presented with progressive abdominal pain after the onset of menarche was diagnosed as OCSCUS using magnetic resonance imaging and treated with hysteroscopic dissection of the uterine part of the septum.

SUMMARY AND CONCLUSION

Greater awareness of the OCSCUS will lead to earlier detection and is the key to alleviating patient suffering and avoiding potentially severe complications, such as endometriosis and infertility. For the treatment of OCSCUS, hysteroscopic dissection of the uterine part of the septum is a minimally invasive treatment choice with low surgical risk.

Ecological study of effects of industrial watershed on Müllerian anomalies in an obstetric population

OBJECTIVE

To ascertain the prevalence of Müllerian anomalies within an obstetrical population in relation to official hazardous waste sites designated by the Environmental Protection Agency (EPA) in West Virginia.

METHODS

Observational study of obstetric patients in a tertiary care center with uterine ultrasounds from January 2006 to June 2017. An Optimized Hot Spot analysis and Ripley's K- Function was constructed to ascertain if there is an association with environmental exposures.

RESULTS

The prevalence of Müllerian anomalies in our obstetric study sample was 0.9% (118/13,040). The most common were septate (47; 39.8%) and bicornuate (46; 39.0%). The distribution of Müllerian anomalies was non-random illustrated by Optimized Hot Spot Analysis locating several statistically significant zip codes of Müllerian anomalies in relation to zip codes that include EPA facilities.

CONCLUSION

The distribution of Müllerian anomalies was clustered in watershed areas along the Kanawha River in West Virginia that have been designated as EPA FRS Sites and Superfund Sites.

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.

Ischemia and reperfusion injury in uterus transplantation: A comprehensive review

Uterus transplantation (UTx) is the only available treatment for human beings who cannot carry children out to term. However, despite several clinical studies with a very limited number of UTx many issues have to be addressed. Up to date, there is a limited number of successful UTx with livebirth and the majority was achieved with live donors. Wide clinical application is inherently limited by the lack of organs, ischemia/reperfusion injury (IRI) as well as immunosuppression after UTx. The objective of this comprehensive literature review is to discuss these arising limitations of UTx with main focus on strategies to reduce IRI. This review showed, that usage of immunosuppressants, opioids or supplements, like amino acids, protects uterus from IRI, improving rising level of antioxidants and decreasing level of oxidative stress markers. The available data of experimental and clinical studies was compiled and will be discussed.

A Review of Mullerian Anomalies and Their Urologic Associations

Structural anomalies of the female reproductive tract, known as Mullerian anomalies, can occur in isolation or in association with anomalies of other organ systems. Due to shared embryology, the most common association in up to 40% of patients is with renal, ureteral, and bladder anomalies. Affected girls can have a wide range of genitourinary symptoms with urologists playing an integral role in their diagnosis and treatment. To facilitate the recognition and management of these conditions, we provide a review of Mullerian anomalies including the embryology, classifications, syndromes, evaluation, and treatments with attention to their urologic applicability.

Asherman's Syndrome: it may not be all our fault

Asherman's Syndrome (AS) is an acquired condition defined by the presence of intrauterine adhesions (IUA) that cause symptoms such as menstrual abnormalities, pelvic pain, infertility, recurrent miscarriage, abnormal placentation and attendant psychological distress. Classically, AS is considered an iatrogenic disease triggered by trauma to the pregnant uterus. Different factors can cause the destruction of the endometrium, thus affecting the endometrial stem cell niche and creating IUAs. Curettage of the pregnant uterus appears to be the most common source of this destruction. Nevertheless, some AS cases have been associated with congenital uterine abnormalities and infections, and there are some idiopathic cases without any prior surgical procedures, suggesting a putative constitutional predisposition to IUA. Factors reported to cause AS share an underlying inflammatory mechanism leading to defective endometrial healing and vascularization. Interestingly, distinct genetic profiles have been observed in the endometrium of AS patients. These data suggest that AS might not just be an iatrogenic complication, but also the result of a genetic predisposition. Elucidating the possible physiopathological processes that contribute to AS will help to identify patients at risk for this condition, providing an opportunity for prevention.

Two Distinctively Rare Syndromes in a Case of Primary Amenorrhea: 18p Deletion and Mayer-Rokitansky-Kuster-Hauser Syndromes

Mayer-Rokitansky-Kuster-Hauser (MRKH) syndrome and 18p deletion syndrome, two genetic disorders having distinct genetic etiologies, have an exceedingly rare likelihood of coexistence. Vaginal agenesis or MRKH syndrome, the developmental failure of Mullerian ductal system-derived structures in a genotypic female fetus (46, XX), leads to congenital absence of uterus and vagina in variable degree. The 18p deletion syndrome is a rare chromosomal disorder, characterized by dysmorphic features, stunted growth, and mental retardation, which is caused by deletion of a part or all of the short arm of chromosome 18. A detailed evaluation of primary amenorrhea in a 16-year-old girl yielded both MRKH syndrome and 18p deletion syndrome. Extensive literature search could not identify any reported case bearing this combination of syndromes. This case presentation and review emphasizes on the importance of karyotyping in MRKH patients having atypical features.

Genetics of human female infertility†

About 10% of women of reproductive age are unable to conceive or carry a pregnancy to term. Female factors alone account for at least 35% of all infertility cases and comprise a wide range of causes affecting ovarian development, maturation of oocytes, and fertilization competence, as well as the potential of a fertilized egg for preimplantation development, implantation, and fetal growth. Genetic abnormalities leading to infertility in females comprise large chromosome abnormalities, submicroscopic chromosome deletion and duplications, and DNA sequence variations in the genes that control numerous biological processes implicated in oogenesis, maintenance of ovarian reserve, hormonal signaling, and anatomical and functional development of female reproductive organs. Despite the great number of genes implicated in reproductive physiology by the study of animal models, only a subset of these genes is associated with human infertility. In this review, we mainly focus on genetic alterations identified in humans and summarize recent knowledge on the molecular pathways of oocyte development and maturation, the crucial role of maternal-effect factors during embryogenesis, and genetic conditions associated with ovarian dysgenesis, primary ovarian insufficiency, early embryonic lethality, and infertility.

Search for altered imprinting marks in Mayer-Rokitansky-Küster-Hauser patients

BACKGROUND

Mayer-Rokitansky-Küster-Hauser syndrome (MRKH) is the second most common cause of primary amenorrhea and characterized by absence of the uterus and the upper part of the vagina. The etiology of MRKH is mainly unknown but a contribution of genomic alterations is probable. A molecular disturbance so far neglected in MRKH research is aberrant methylation at imprinted loci. In fact, MRKH has been reported in patients with the imprinting disorder Silver-Russell syndrome.

METHODS

We report on a rare patient with MRKH and SRS due to an ICR1 hypomethylation in 11p15.5. On the basis of this observation we screened a large cohort of MRKH patients (n > 100) for aberrant methylation at nine imprinted loci.

RESULTS

We failed to detect any epimutation, thus we conclude that imprinting defects at least at the currently known disease-relevant imprinted loci do not contribute to the isolated MRKH phenotype. However, it cannot be excluded that altered methylation marks at other loci are involved in the etiology of MRKH.

CONCLUSION

The molecular basis for MRKH remains unclear in the majority of patients, but future studies on the association between MRKH and ICR1 hypomethylation/SRS will to enlighten the role of epigenetics in the etiology of MRKH.

Disorders of sex development

Normal sex development depends on the precise spatio-temporal sequence and coordination of mutually antagonistic activating and repressing factors. These factors regulate the commitment of the unipotential gonad into the binary pathways governing normal sex development. Typically, the presence of the SRY gene on the Y chromosome triggers the cascade of molecular events that lead to male sex development. Disorders of sex development comprise a heterogeneous group of congenital conditions associated with atypical development of internal and external genitalia. These disorders are generally attributed to deviations from the typical progression of sex development. Disorders of sex development can be classified into several categories including chromosomal, gonadal, and anatomic abnormalities. Genetic tools such as microarray analyses and next-generation sequencing techniques have identified novel genetic variants among patients with disorders of sexual development. Most importantly, patient management needs to be individualized, especially for decisions related to sex of rearing, surgical interventions, hormone treatment, and potential for fertility preservation.

A novel mutation of HOXA11 in a patient with septate uterus

BACKGROUND

The etiology of Müllerian duct anomalies (MDAs) is poorly understood at present. The HOXA11 gene is crucial for the development of the Müllerian duct. The objective of this study is to report a unique case of MDAs with a novel mutation in HOXA11.

RESULTS

We identified a potential disease-causing mutation (p. E255K) in a patient with a septate uterus. The mutation was not detected in 169 control subjects or listed in any databases of variations. Bioinformatic predictions and functional studies showed that the mutation reduces the DNA binding affinity and disrupts transactivation ability of HOXA11.

CONCLUSION

In conclusion, this is the first report to describe a HOXA11 mutation in Chinese women with MDAs. The results demonstrated that mutation in HOXA11 can contribute to the etiology of MDAs, especially the septate uterus, but might not be a common cause.

Endometriosis in Adolescent and Young Girls: Report on a Series of 55 Cases

STUDY OBJECTIVE

The aim of this retrospective study was to evaluate endometriosis in adolescent and young girls and further to review the menstrual, reproductive characteristics, and risk factors.

DESIGN AND SETTING

We reviewed the medical records of adolescent and young girls with endometriosis from 2 different countries. Data were collected and analyzed from charts of 900 patients with endometriosis.

PARTICIPANTS AND INTERVENTIONS

Fifty-five female adolescents aged between 13 and 21 years (mean age 18.3 years) participated in our series. This study was conducted in the Obstetric and Gynecology Department of Venizeleio General Hospital of Crete and involved all patients diagnosed with endometriosis between 1996 and 2016.

MAIN OUTCOME MEASURES

Statistical methods included χ² and Mann-Whitney U test.

RESULTS

Of 900 patients with endometriosis we found 55 female adolescents (6.1%). The mean age was 18.3 ± 2.3 years, significantly younger compared with the advanced endometriosis patients (32.7 ± 7.2; P < .001). Regarding the menstrual reproductive and others characteristics, we observed several differences in adolescent young girls compared with the advanced age endometriosis group. The factors associated with an increased risk for young women include age at menarche, dysmenorrhea, history of asthma, and a positive family history of endometriosis. Additionally, we report on 16 of 55 (32%) adolescent women with endometriosis and congenital malformations (P < .01) and 5 patients who were diagnosed with dry eye syndrome.

CONCLUSION

There is an association between endometriosis in adolescent and young women and risk factors including early menarche, early onset of dysmenorrhea, history of asthma, previous surgical procedures, obstructive genital anomalies, and family history of endometriosis.

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.