Clinical and molecular characterization of the bladder exstrophy-epispadias complex: analysis of 232 families

Bladder exstrophy-epispadias-cloacal exstrophy complex: characteristics, aetiologies, and epidemiologic findings

Bladder exstrophy-epispadias-cloacal exstrophy complex (BEEC) is a spectrum of congenital urologic anomalies that involve the bladder, urethra, genitalia, and pelvic musculoskeletal system, and can affect urinary continence, sexual health, and fertility. BEEC includes a wide spectrum of anatomical abnormalities with different levels of severity: epispadias represents the mildest phenotype, classic bladder exstrophy (CBE) is the most common defect, and cloacal exstrophy (CE) - often referred to as omphalocele, exstrophy, imperforate anus, and spinal defects (OEIS) complex - is the most severe form. BEEC disorders cause significant health problems and affect the health-related quality of life (QoL) of affected individuals. There have been significant insights into the aetiology of BEEC in the last decade. Specifically, recent genetic studies have suggested that downstream regulator(s) of p63, Isl1, and other genes may play a role in the failure of the lower urinary tract to close. This narrative review outlines the unique anatomy of bladder exstrophy (BE) and epispadias, with a brief mention of the anatomy found in CE. A literature review using PubMed and Google Scholar databases was used to identify relevant articles on the outlined topics without placing any limitations on publication years or study designs. We included full-text English articles published in peer-reviewed journals related to the terms: "exstrophy" & "epispadias" AND "aetiology", "embryology" and "incidence". We summarise the epidemiology of this rare complex - including what is known about its incidence in Africa - before presenting recent advances in comparative genetics from mouse models and human studies that provide insights into BEEC pathogenesis.

Updates on the Care of Cloacal Exstrophy

Cloacal exstrophy is the most severe congenital anomaly of the exstrophy-epispadias complex and is characterized by gastrointestinal, genitourinary, neurospinal, and musculoskeletal malformations. Individualized surgical reconstruction by a multidisciplinary team is required for these complex patients. Not infrequently, patients need staged surgical procedures throughout childhood and adolescence. Following significant improvements in medical care and surgical reconstructive techniques, nearly all patients with cloacal exstrophy now survive, leading to an increased emphasis on quality of life. Increased attention is given to gender identity and the implications of reconstructive decisions. Long-term sequelae of cloacal exstrophy, including functional continence and sexual dysfunction, are recognized, and many patients require ongoing complex care into adulthood.

De novo variants identified by trio whole exome sequencing of bladder exstrophy epispadias complex

Bladder exstrophy epispadias complex (BEEC) encompasses a spectrum of conditions ranging from mild epispadias to the most severe form: omphalocele-bladder exstrophy-imperforate anus-spinal defects (OEIS). BEEC involves abnormalities related to anatomical structures that are proposed to have a similar underlying etiology and pathogenesis. In general, BEEC, is considered to arise from a sequence of events in embryonic development and is believed to be a multi-etiological disease with contributions from genetic and environmental factors. Several genes have been implicated and mouse models have been generated, including a knockout model of p63, which is involved in the synthesis of stratified epithelium. Mice lacking p63 have undifferentiated ventral urothelium. MNX1 has also been implicated. In addition, cigarette smoking, diazepam and clomid have been implied as environmental factors due to their relative association. By in large, the etiology and pathogenesis of human BEEC is unknown. We performed de novo analysis of whole exome sequencing (WES) of germline samples from 31 unrelated trios where the probands have a diagnosis of BEEC syndrome. We also evaluated the DECIPHER database to identify copy number variants (CNVs) in genes in individuals with the search terms "bladder exstrophy" in an attempt to identify additional candidate genes within these regions. Several de novo variants were identified; however, a candidate gene is still unclear. This data further supports the multi-etiological nature of BEEC.

Exstrophy-Epispadias Complex

Exstrophy-epispadias complex encompasses a spectrum of disorders with lower abdominal midline malformations, including epispadias, bladder exstrophy, and cloacal exstrophy, also known as Omphalocele-Exstrophy-Imperforate Anus-Spinal Anomalies Complex. In this review, the authors discuss the epidemiology, embryologic cause, prenatal findings, phenotypic characteristics, and management strategies of these 3 conditions. The primary focus is to summarize outcomes pertaining to each condition.

Genetic Counseling for Bladder Exstrophy-Epispadias Complex

Bladder exstrophy-epispadias complex (BEEC) represents the severe end of the uro-rectal malformation spectrum and has profound impact on continence, sexual, and renal function. Treatment of BEEC is primarily surgical, and the main goals are safe closure of the abdominal wall, urinary continence while preserving renal function, and adequate cosmetic and functional genital reconstruction. Psychosocial and psychosexual outcomes and adequate health-related quality of life depend on long-term multidisciplinary care. The overall outcome is now considered very positive and affected individuals usually lead self-determined and independent lives with the desire to start their own families later in life. Certainty about the risk of recurrence and the provision of information about the current state of knowledge about the identified genetic causes with high penetrance will have an impact on family planning for healthy parents with an affected child and for affected individuals themselves. This review addresses this information and presents the current state of knowledge.

The Genomic Architecture of Bladder Exstrophy Epispadias Complex

The bladder exstrophy-epispadias complex (BEEC) is an abdominal midline malformation comprising a spectrum of congenital genitourinary abnormalities of the abdominal wall, pelvis, urinary tract, genitalia, anus, and spine. The vast majority of BEEC cases are classified as non-syndromic and the etiology of this malformation is still unknown. This review presents the current knowledge on this multifactorial disorder, including phenotypic and anatomical characterization, epidemiology, proposed developmental mechanisms, existing animal models, and implicated genetic and environmental components.

Long-term Kidney Outcomes in Exstrophy-Epispadias Complex: How Patients Present as Adults

OBJECTIVE

To characterize kidney function in patients with exstrophy-epispadias complex (EEC) at time of presentation for adult urologic care.

MATERIALS AND METHODS

This was a retrospective analysis of 23 patients (ages 18-57) with EEC who presented to a single tertiary care center from 2001-2020. Kidney function was evaluated based on calculated eGFR and presence of hydronephrosis on imaging. UDS data was used to evaluate the bladder.

RESULTS

Patients had undergone a variety of different surgical techniques for exstrophy or epispadias repair prior to presentation to an adult urologist. We found that 10 of the 23 patients had evidence of CKD Stage II or higher at the time of presentation and 7 patients had evidence of hydronephrosis on imaging. There was urodynamics data available for 14 patients, of which 8 patients showed poor (≤15 ml/cmH₂O) or intermediate (15-20 ml/cmH₂O) bladder compliance.

CONCLUSION

In conclusion, some patients with EEC have evidence of kidney dysfunction at time of presentation to an adult urologist. It is important to consider this when caring for patients with EEC as adults.

A Prevalence Estimation of Exstrophy and Epispadias in Germany From Public Health Insurance Data

Introduction: The prevalence of rare diseases is very important for health care research. According to the European Surveillance of Congenital Anomalies (EUROCAT) registers, the live prevalence for exstrophy and/or epispadias (grades 1-3) is reported with 1:23,255 (95% CI: 1:26,316; 1:20,000). A Europe-wide prevalence evaluation based on reports from excellence centers estimates a prevalence for exstrophies of 1:32,200 and for isolated epispadias of 1:96,800 in 2010. However, the frequency of exstrophy [International Statistical Classification of Diseases and Related Health Problems revision 10 (ICD-10): Q64.1] and epispadias (ICD-10: Q64.0) treated in different age groups in Germany remains unclear. Material and Method: Public health insurance data from 71 million people (approximately 87% of the population) were provided by the German Institute for Medical Documentation and Information (DIMDI) in accordance to the German Social Insurance Code for this research purpose. DIMDI analyzed the data source for the ICD diagnoses exstrophy and epispadias between 2009 and 2011. As provided data were robust over the years, averaged data are mentioned. Detailed subgroup analysis of small numbers was forbidden due to privacy protection. Results: Annually, 126 persons of all ages with epispadias and 244 with exstrophy are treated as inpatients. In the observed population, 34 infants (<1 year of age) with epispadias and 19 with exstrophy (58% male) are treated as outpatients each year. This corresponds to an estimated live prevalence of 1:11,000 (95% CI: 1:14,700; 1:8,400) for EEC (exstrophy-epispadias complex), more specifically a prevalence of 1:17,142 for epispadias and of 1:30,675 for exstrophy. The male-to-female ratio for exstrophy is 1.4:1 for infants and 1.6:1 for all minors. In children and adolescents, 349 epispadias and 393 exstrophies (up to the age of 17) are treated annually, whereas adults with exstrophy and even more with epispadias make comparatively less use of medical care. Conclusion: With the help of DIMDI data, the live prevalence of bladder exstrophy and epispadias in Germany could be estimated. The prevalence of epispadias was higher than in previous reports, in which milder epispadias phenotypes (grade 1 or 2) may not have been included. These analyses might enlighten knowledge about nationwide incidence and treatment numbers of rare diseases such as the EEC.

TopClosure® tension-relief system for immediate primary abdominal defect repair in an adult patient with bladder exstrophy

Bladder exstrophy during adulthood is a rare deformity. A major surgical challenge encountered in bladder exstrophy cases is the repair of an anterior abdominal wall defect. The TopClosure® tension-relief system (TRS) is a simple and practical skin stretching and wound closure-secure system that can be useful in treating patients with bladder exstrophy. A 61-year-old man presented with a congenital bladder valgus and epispadias. The dorsal side of the penis was split. The patient underwent valgus cystectomy, bilateral ureteral skin stoma creation, and primary closure of the large defect of the anterior abdominal wall using the TopClosure® TRS. At the 1-year follow-up after surgery, the patient had recovered well, and there were no indications of major complications. Utilization of the TopClosure® TRS to repair the large abdominal defect is an innovative method for abdominal reconstruction. The TopClosure® TRS reduces operative time and the duration of hospital stay and improves wound aesthetics.

Evaluation of the ISL1 gene in the pathogenesis of bladder exstrophy in a Swedish cohort

Bladder exstrophy is a congenital closure defect of the urinary bladder with a profound effect on morbidity. Although the malformation is usually sporadic, a genetic background is supported by an increased recurrence risk in relatives, higher concordance rates in monozygotic twins and several associated chromosomal aberrations. Recently, the ISL1 gene was presented as a candidate gene for bladder exstrophy and epispadias complex (BEEC) development in two different studies. In our study, we screened for genetic variants in the ISL1 gene in DNA from 125 Swedish patients using Sanger sequencing and array-CGH analysis. In addition, we evaluated ISL1 expression in RNA of human bladder during embryonic and fetal weeks 5–10 relative to that in lung tissue (week 9). In total, 21 single-nucleotide variants were identified, including a potentially novel missense variant, c.137C>G p.(Ala46Gly), substituting a conserved amino acid. This variant was inherited from an unaffected mother. No structural variants were identified. RNA sequencing revealed ISL1 mRNA expression during the critical time frame of human bladder development. In conclusion, we did not detect any known or likely pathogenic variants in the ISL1 gene in 125 Swedish BEEC patients, indicating that variation in the ISL1 gene is not a common genetic mechanism of BEEC development in the Swedish population.

Clinical and risk factor analysis of cloacal defects in the National Birth Defects Prevention Study

Cloacal exstrophy (CE) and persistent cloaca (PC) (alternatively termed urorectal septum malformation sequence [URSMS]), represent two major cloacal defects (CDs). Clinical characteristics and risk factors often are studied for both defects combined, rather than exploring if these defects have different etiologies. We enumerated clinical features for 47 CE and 54 PC (inclusive of URSMS) cases from the National Birth Defects Prevention Study. Thirty-three CE cases were classified as isolated and 14 as multiple (presence of unassociated major defects); respective totals for PC cases were 26 and 28. We compared selected child and maternal characteristics between 11,829 non-malformed controls and CE and PC cases using chi-square or Fisher's exact tests. Compared to controls, CE and PC cases were statistically more likely (p < 0.05) to be preterm; CE cases were more likely to be multiple births. We conducted logistic regression analysis to estimate odds ratios and 95% confidence intervals for any CD, CE, and PC with selected self-reported maternal prepregnancy and periconceptional (one month prior to 3 months following conception) exposures. In crude and adjusted analyses, we observed significant positive associations for any CD, CE, and PC with use of any fertility medication or assisted reproductive technology procedure. Significant positive associations observed only in crude analyses were any CD with maternal obesity or use of progesterone, any CD and CE with any x-ray, and any CD and PC with use of folate antagonist medications. Our findings provide some of the first insights into potential differing etiologies for CE and PC.

Discordant Anomalies with Combined Features of Pentalogy of Cantrell and OEIS Complex: A Case Report in Monochorionic Twins

INTRODUCTION

Ventral body wall defects have various manifestations. Among others, pentalogy of Cantrell (PC) and omphalocele exstrophy imperforate anus spinal abnormalities (OEIS) complex are defects that involve upper and lower anterior midline of body wall, respectively. Although both entities are in a spectrum of ventral body wall defects, the combination of PC and OEIS complex has not been described.

CASE REPORT

In this report, we describe an unusual case of congenital ventral body wall defect with combined features of PC and OEIS complex, which discordantly occurred in monochorionic monoamniotic twins.

CONCLUSION

PC and OEIS complex may be related regarding their embryologic origins. The combination may represent the most severe manifestation of ventral body wall defects.

Exstrophy Bladder - Reconstruction or Diversion for the Underprivileged

The surgical techniques for management of bladder exstrophy epispadias complex have evolved from staged reconstruction, complete primary repair to radical mobilization. Post-operative complications add to the multiplicity of surgical procedures at each step. The end results are variable with many achieving continence rates of 85-89% only after bladder augmentation and clean intermittent catheterization. The situation is further complicated in resource-poor settings, where illiteracy and poverty are the driving factors for choosing a single operative procedure for creation of low pressure reservoir aiming at upper tract preservation and good primary continence. Thus, primary urinary diversion should be offered as a surgical option to patients with limited access to health care facilities. Yogesh's cystorectostomy is a modification of Heitz-Boyer-Hovelacque procedure, wherein the bladder plate is directly anastomosed to the recto-sigmoid pouch, without mobilizing the ureters from their original location. The short-term follow-ups are encouraging with all achieving total urinary continence over the ensuing months. The upper tract functions are well preserved, along with huge parental and patient satisfaction and overall improvement in the quality of life.

Qualitative questionnaire on the psychosocial wellbeing of mothers of children with BEEC

INTRODUCTION

The bladder exstrophy-epispadias complex (BEEC) represents a spectrum of malformations that affect the anatomical and functional structure of the urogenital system. The parents of patients affected by this condition are subject to particularly stressful situations, such as worrying about their child's health, long hospital stays, concerns about the health and constant need for personal care for their children, that can profoundly compromise the quality of family life.

OBJECTIVE

The objective of this explorative qualitative study is to evaluate the social situation and the psychological strategies implemented by the mothers of children between 6 and 10 years of age who are affected by BEEC.

STUDY DESIGN

Fourteen mothers of children aged 6-10 years and affected by BEEC (9 boys and 5 girls) were interviewed. Data on the mothers' experiences were collected through semi-structured interviews (Table).

RESULTS

The qualitative analysis of the interviews showed that participants described experiences that were characterised by emotions such as fear and anger. Each mother had implemented a different and, sometimes, dysfunctional strategy in order to cope with the complex situation of the son/daughter. The aspects that most clearly emerged from mothers' descriptions were (1) the traumatic situation at the birth of the baby, (2) the sense of embarrassment concerning the pathological condition as the child was growing and the consequent sense of isolation of the mother, and (3) the fluctuation of feelings towards the multidisciplinary staff, which was sometimes seen as an important source of help and some other times as too destabilising and not helpful at all.

DISCUSSION

The study provided some insight into the psychological and social conditions experienced by mothers of children with BEEC, which could serve as a basis for developing multidisciplinary teams with greater awareness about families living with this condition and better timing in addressing their needs.

CONCLUSIONS

Mothers of children with BEEC show emotional and social difficulties. This is a crucial aspect to consider when planning a multidisciplinary approach to the treatment/therapy, especially considering that children examined in this study are approaching adolescence.

CNV analysis in 169 patients with bladder exstrophy-epispadias complex

Background

The bladder exstrophy-epispadias complex (BEEC) represents the severe end of the congenital uro-rectal malformation spectrum. Initial studies have implicated rare copy number variations (CNVs), including recurrent duplications of chromosomal region 22q11.21, in BEEC etiology.

Methods

To detect further CNVs, array analysis was performed in 169 BEEC patients. Prior to inclusion, 22q11.21 duplications were excluded using multiplex ligation-dependent probe amplification.

Results

Following the application of stringent filter criteria, seven rare CNVs were identified: n = 4, not present in 1307 in-house controls; n = 3, frequency of <0.002 in controls. These CNVs ranged from 1 to 6.08 Mb in size. To identify smaller CNVs, relaxed filter criteria used in the detection of previously reported BEEC associated chromosomal regions were applied. This resulted in the identification of six additional rare CNVs: n = 4, not present in 1307 in-house controls; n = 2, frequency <0.0008 in controls. These CNVs ranged from 0.03–0.08 Mb in size. For 10 of these 13 CNVs, confirmation and segregation analyses were performed (5 of maternal origin; 5 of paternal origin). Interestingly, one female with classic bladder extrophy carried a 1.18 Mb duplication of 22q11.1, a chromosomal region that is associated with cat eye syndrome.

Conclusions

A number of rare CNVs were identified in BEEC patients, and these represent candidates for further evaluation. Rare inherited CNVs may constitute modifiers of, or contributors to, multifactorial BEEC phenotypes.

Genetics of Bladder-Exstrophy-Epispadias Complex (BEEC): Systematic Elucidation of Mendelian and Multifactorial Phenotypes

The Bladder-Exstrophy-Epispadias Complex (BEEC) represents the severe end of the uro-rectal malformation spectrum, and has a profound impact on continence, and on sexual and renal function. While previous reports of familial occurrence, in-creased recurrence among first-degree relatives, high concordance rates among monozygotic twins, and chromosomal aberra-tions were suggestive of causative genetic factors, the recent identification of copy number variations (CNVs), susceptibility regions and genes through the systematic application of array based analysis, candidate gene and genome-wide association studies (GWAS) provide strong evidence. These findings in human BEEC cohorts are underscored by the recent description of BEEC(-like) murine knock-out models. Here, we discuss the current knowledge of the potential molecular mechanisms, mediating abnormal uro-rectal development leading to the BEEC, demonstrating the importance of ISL1-pathway in human and mouse and propose SLC20A1 and CELSR3 as the first BEEC candidate genes, identified through systematic whole-exome sequencing (WES) in BEEC patients.

Bladder exstrophy-epispadias complex and the role of methylenetetrahydrofolate reductase C677T polymorphism: A case control study

Purpose:

The Bladder Exstrophy-Epispadias Complex (BEEC) is the most serious form of midline abdominal malformation. The etiology of BEEC is unknown and is thought to be multifactorial. Methylenetetrahydrofolate reductase (MTHFR) polymorphism C677T is strongly associated with other midline abnormalities such as neural tube defects. No proper case-control study existed comparing MTHFR polymorphism with BEEC. We sought to find an association with MTHFR polymorphism and patients with bladder exstrophy (BE).

Materials and Methods:

The design of the study was a case-control study, involving 50 children with BEEC and 50 normal healthy school children. Genetic analysis for MTHFR 677 polymorphism was carried out after DNA extraction and polymerase chain reaction amplification. Epidemiological analysis was done by using the birth defect questionnaire on parents of BEEC.

Results:

Forty-two classical BE, two cloacal exstrophies (CE), four epispadias, and two exstrophy variant patients were a part of this study. Severe variety of BE had a significant association with C667T MTHFR polymorphism as compared to the normal control population (P = 0.01).

Conclusion:

C677T MTHFR polymorphism has a strong association with severe variety (CE) of BEEC occurrence.

Genome-wide association study and meta-analysis identify ISL1 as genome-wide significant susceptibility gene for bladder exstrophy

The bladder exstrophy-epispadias complex (BEEC) represents the severe end of the uro-rectal malformation spectrum, and is thought to result from aberrant embryonic morphogenesis of the cloacal membrane and the urorectal septum. The most common form of BEEC is isolated classic bladder exstrophy (CBE). To identify susceptibility loci for CBE, we performed a genome-wide association study (GWAS) of 110 CBE patients and 1,177 controls of European origin. Here, an association was found with a region of approximately 220kb on chromosome 5q11.1. This region harbors the ISL1 (ISL LIM homeobox 1) gene. Multiple markers in this region showed evidence for association with CBE, including 84 markers with genome-wide significance. We then performed a meta-analysis using data from a previous GWAS by our group of 98 CBE patients and 526 controls of European origin. This meta-analysis also implicated the 5q11.1 locus in CBE risk. A total of 138 markers at this locus reached genome-wide significance in the meta-analysis, and the most significant marker (rs9291768) achieved a P value of 2.13 × 10-12. No other locus in the meta-analysis achieved genome-wide significance. We then performed murine expression analyses to follow up this finding. Here, Isl1 expression was detected in the genital region within the critical time frame for human CBE development. Genital regions with Isl1 expression included the peri-cloacal mesenchyme and the urorectal septum. The present study identified the first genome-wide significant locus for CBE at chromosomal region 5q11.1, and provides strong evidence for the hypothesis that ISL1 is the responsible candidate gene in this region.

Genome-wide association study and mouse expression data identify a highly conserved 32 kb intergenic region between WNT3 and WNT9b as possible susceptibility locus for isolated classic exstrophy of the bladder

Bladder exstrophy-epispadias complex (BEEC), the severe end of the urorectal malformation spectrum, has a profound impact on continence as well as sexual and renal functions. It is widely accepted that for the majority of cases the genetic basis appears to be multifactorial. Here, we report the first study which utilizes genome-wide association methods to analyze a cohort comprising patients presenting the most common BEEC form, classic bladder exstrophy (CBE), to identify common variation associated with risk for isolated CBE. We employed discovery and follow-up samples comprising 218 cases/865 controls and 78 trios in total, all of European descent. Our discovery sample identified a marker near SALL1, showing genome-wide significant association with CBE. However, analyses performed on follow-up samples did not add further support to these findings. We were also able to identify an association with CBE across our study samples (discovery: P = 8.88 × 10(-5); follow-up: P = 0.0025; combined: 1.09 × 10(-6)) in a highly conserved 32 kb intergenic region containing regulatory elements between WNT3 and WNT9B. Subsequent analyses in mice revealed expression for both genes in the genital region during stages relevant to the development of CBE in humans. Unfortunately, we were not able to replicate the suggestive signal for WNT3 and WNT9B in a sample that was enriched for non-CBE BEEC cases (P = 0.51). Our suggestive findings support the hypothesis that larger samples are warranted to identify association of common variation with CBE.

Blastopathies and microcephaly in a Chornobyl impacted region of Ukraine

This population-based descriptive epidemiology study demonstrates that rates of conjoined twins, teratomas, neural tube defects, microcephaly, and microphthalmia in the Rivne province of Ukraine are among the highest in Europe. The province is 200 km distant from the Chornobyl site and its northern half, a region known as Polissia, is significantly polluted by ionizing radiation. The rates of neural tube defects, microcephaly and microphthalmia in Polissia are statistically significantly higher than in the rest of the province. A survey of at-birth head size showed that values were statistically smaller in males and females born in one Polissia county than among neonates born in the capital city. These observations provide clues for confirmatory and cause-effect prospective investigations. The strength of this study stems from a reliance on international standards prevalent in Europe and a decade-long population-based surveillance of congenital malformations in two distinct large populations. The limitations of this study, as those of other descriptive epidemiology investigations, is that identified cause-effect associations require further assessment by specific prospective investigations designed to address specific teratogenic factors.

New insights into the pathogenesis of bladder exstrophy-epispadias complex

Bladder exstrophy-epispadias complex (BEEC) is a complex and debilitating congenital disease. Familial and twin studies suggest a possible genetic component in BEEC pathogenesis. Bladder mesenchyme (detrusor) development requires induction by a signal from bladder urothelium, and we and others have shown the Shh-Gli-Bmp4 signalling pathway is likely to be involved. P63 is a master regulator in epithelial stratification and is expressed in urothelium. We have shown that p63 knock-out mice undergo excessive urothelial apoptosis. Failure of mesenchymal induction by epithelium leads to BEEC. We further demonstrated that insertion/deletion (in/del) polymorphisms (1 base pair (bp) ins and 4 bp ins., and 12 bp del) in the ΔNP63 promoter reduce transcriptional efficiency, and are associated with a statistically significant increase in the risk of BEEC in humans. Furthermore, a Genome-Wide Expression Profiling (GWEP) study suggests possible involvement of PERP in human BEEC. Intriguingly, PERP is a direct target of p63 during development, and is also involved in epithelial stratification. PERP co-localizes with desmosome, and both PERP and desmosome are essential for maintaining tissue integrity by cellular adhesion and epithelial stratification. A recent study showed that PERP and desmosome expression levels are abnormal in human BEEC patients. This review describes the role of the P63 > PERP > desmosome pathway in the development of human bladder during embryogenesis. We hypothesize that disruption of this pathway may increase the risk of BEEC.

No TAP63 promoter mutation is detected in bladder exstrophy-epispadias complex patients

BACKGROUND/PURPOSE

Bladder exstrophy-epispadias complex (BEEC) is thought to have a genetic component in its pathogenesis. Previously we found that p63(-/-) mice show increased ventral apoptosis and develop a BEEC phenotype. Down-regulation of the anti-apoptotic ΔNP63 and an up-regulation of pro-apoptotic TAP63 isoforms have been demonstrated in BEEC patient bladder tissues. We have previously shown that insertion/deletion polymorphisms of the ΔNp63 promoter are associated with an increased risk of BEEC. In this study, we specifically examined the TAP63 promoter to see if any sequence changes might lead to up-regulation of TAP63 and exaggerated apoptosis in BEEC patients.

METHODS

i) Bioinformatic analysis of the TAP63 promoter was performed to identify putative regulatory regions. ii) High-resolution Melt and Sanger sequencing was used to screen targeted regions in 112 BEEC patient DNA samples for potential sequence variants. iii) Sequence variation was analysed for significance against normal population frequency data.

RESULTS

i) We identified multiple epigenetic markers of transcriptional regulation within highly conserved areas of the TAP63 promoter sequence. ii) Of the 112 buccal swab DNA samples, adequate and successful screening ranged between 48 and 67 for each region. iii) No novel sequence variation or mutation was uncovered. iv) Two known SNPs were identified. However, allele frequency analysis was not statistically significant.

CONCLUSION

Our data do not associate genetic variation within the TAP63 promoter region with an increased risk of BEEC. Our data so far suggests that only ΔNP63 promoter aberration is involved in BEEC pathogenesis.

Urological outcomes in the omphalocele exstrophy imperforate anus spinal defects (OEIS) complex: experience with 80 patients

OBJECTIVE

To review the urological management and outcomes of patients with the OEIS (omphalocele, exstrophy of the bladder, imperforate anus, spinal abnormalities) complex.

PATIENTS AND METHODS

80 patients with the OEIS complex managed at a single institution between 1974 and 2009 were reviewed.

RESULTS

37 had initial closure at our institution (2 failed - 5%); 22 with successful closure were referred for incontinence; 15 failed closure at an outside institution (2 of whom are awaiting closure); 6 are skin-covered variants. Osteotomy was performed in 39/43 (91%) with successful closure versus 8/17 (47%) who failed initial bladder closure. 40 were dry (56%), but most needed additional urinary reconstruction: 2 had small bowel neobladders; 32 (84%) had augmentation cystoplasty; 30 (79%) had a continent catheterizable channel; only 9 (24%) were continent with an intact urethra. Bladder neck reconstruction allowed dryness in 7 (18%). 45 patients had XY genotype--19 had female gender assignment at birth. All patients with XX genotype had female gender assignment.

CONCLUSIONS

Osteotomy improves success of initial bladder closure. A bladder neck procedure, catheterizable channel, and augmentation cystoplasty will be required in the majority of patients to attain urinary dryness.

CNV analysis in monozygotic twin pairs discordant for urorectal malformations

Early post-twinning mutational events can account for discordant phenotypes in monozygotic (MZ) twin pairs. Such mutational events may comprise genomic alterations of different sizes, ranging from single nucleotides to large copy-number variations (CNVs). Anorectal malformations (ARM) and the bladder exstrophy-epispadias complex (BEEC) represent the most severe end of the urorectal malformation spectrum. Recently, CNV studies in patients with sporadic ARM and the BEEC have identified de novo events that occur in specific chromosomal regions. We hypothesized that early arising, post-twinning CNVs might contribute to discordance in MZ twin pairs with ARM or the BEEC; knowledge of such CNVs might help to identify additional chromosomal regions involved in the development of these malformations. We investigated four discordant MZ twin pairs (three ARM and one BEEC) using molecular karyotyping arrays comprising 1,140,419 markers with a median marker spacing of 1.5 kb. Filtering the coding regions for possible disease-causing post-twinning de novo CNVs present only in the affected twin, but not in the unaffected twin or the parents, identified a total of 136 CNVs. These 136 CNVs were then filtered against publicly available databases and finally re-evaluated visually. No potentially causative CNV remained after applying these filter criteria. Our results suggest that post-twinning CNV events that affect coding regions of the genome did not contribute to the discordant phenotypes in MZ twin pairs that we investigated. Possible causes for the discordant phenotypes include changes in regulatory elements or smaller genetic changes within coding regions which may be detectable by whole-exome sequencing.

Y chromosome aberration in a patient with cloacal-bladder exstrophy-epispadias complex: an unusual finding

Chromosome aberrations or genetic syndromes associated with cloacal-bladder exstrophy complex have rarely been reported. The aim of this report is to describe a 14 year-old female Brazilian patient with a complex urogenital malformation, short stature, lack of secondary se-xual characteristics and Y chromosome aberration. A girl with cloacal bladder exstrophy complex was referred for evaluation of short stature and absence of secondary sexual characteristics. Pre-pubertal levels of gonadotropins and sex steroids were observed at the beginning of monitoring, but follow-up showed a progressive increase in testosterone levels. The patient underwent gonadectomy and testicular tissue was identified without dysgenetic characteristics. She had a 46,X,inv(Y)(p11.1q11.2) karyotype, normal SRY sequence, and no Y deletions. The pericentric inversion of Y chromosome apparently did not contribute to the development of the complex urogenital malformation in this patient. Currently, no teratogenic agent, environmental factor, or defective genes have been recognized as etiologic factors for this type of urogenital malformation.

Insertion/deletion polymorphisms in the ΔNp63 promoter are a risk factor for bladder exstrophy epispadias complex

Bladder exstrophy epispadias complex (BEEC) is a severe congenital anomaly; however, the genetic and molecular mechanisms underlying the formation of BEEC remain unclear. TP63, a member of TP53 tumor suppressor gene family, is expressed in bladder urothelium and skin over the external genitalia during mammalian development. It plays a role in bladder development. We have previously shown that p63^−/− mouse embryos developed a bladder exstrophy phenotype identical to human BEEC. We hypothesised that TP63 is involved in human BEEC pathogenesis. RNA was extracted from BEEC foreskin specimens and, as in mice, ΔNp63 was the predominant p63 isoform. ΔNp63 expression in the foreskin and bladder epithelium of BEEC patients was reduced. DNA was sequenced from 163 BEEC patients and 285 ethnicity-matched controls. No exon mutations were detected. Sequencing of the ΔNp63 promoter showed 7 single nucleotide polymorphisms and 4 insertion/deletion (indel) polymorphisms. Indel polymorphisms were associated with an increased risk of BEEC. Significantly the sites of indel polymorphisms differed between Caucasian and non-Caucasian populations. A 12-base-pair deletion was associated with an increased risk with only Caucasian patients (p = 0.0052 Odds Ratio (OR) = 18.33), whereas a 4-base-pair insertion was only associated with non-Caucasian patients (p = 0.0259 OR = 4.583). We found a consistent and statistically significant reduction in transcriptional efficiencies of the promoter sequences containing indel polymorphisms in luciferase assays. These findings suggest that indel polymorphisms of the ΔNp63 promoter lead to a reduction in p63 expression, which could lead to BEEC.

Bladder exstrophy epispadias complex is a severe congenital abnormality. The affected babies' bladders are born open, leaking urine constantly. Treatment involves multiple major reconstructive surgeries and the need for lifelong care for the complications of the disease. Although a number of studies have suggested a genetic cause of the disease, the genetic and molecular mechanism underlying the formation of BEEC remains unknown. One gene, TP63, plays a crucial role in the early bladder development. Two different genetic promoters of TP63 produce different forms of the protein with opposing properties. We have shown mice lacking p63 displayed a deformity complex identical to human BEEC. There are no genetic mutations in the p63 protein in BEEC, so genetic variants in the promoter could alter protein expression. Our hypothesis was that loss of p63 expression due to sequence polymorphisms in a promoter is a risk factor for BEEC. We found promoter sequence variants that were statistically associated with the disease and the sequence variant location varied between Caucasian and non-Caucasian patients. This is particularly important as Caucasian populations have a higher risk of BEEC. These findings provide an explanation of BECC and a base for further study of TP63 related genes in this disease.

Successful pregnancy and delivery in a patient with bladder exstrophy

Bladder exstrophy (BE) is a rare congenital anomaly. Owing to the advanced reconstructive surgical techniques and effective antibiotics, the incidence of urinary and systemic complications in patients with BE has decreased and the life expectancy has increased. However, this brings along social, sexual, and psychological problems; particularly, successful pregnancy and delivery is extremely rare in females with BE. We present a pregnancy of an 18-year-old female with BE, who has been followed at our university hospital since birth.

Phenotype severity in the bladder exstrophy-epispadias complex: analysis of genetic and nongenetic contributing factors in 441 families from North America and Europe

OBJECTIVE

To identify genetic and nongenetic risk factors that contribute to the severity of the bladder exstrophy-epispadias complex (BEEC).

STUDY DESIGN

Patients with BEEC from North America (n = 167) and Europe (n = 274) were included. The following data were collected: associated anomalies, parental age at conception, mode of conception, periconceptional folic acid supplementation, maternal risk factors during pregnancy, and environmental risk factors. The patients were divided into 3 subgroups according to phenotype severity: (i) mild, epispadias (n = 43); (ii) intermediate, classic bladder exstrophy (n = 366); and (iii) severe, cloacal exstrophy (n = 31). These subgroups then were compared with identify factors that contribute to phenotype severity.

RESULTS

Males were overrepresented in all subgroups. A relatively high prevalence of cleft lip, with or without cleft palate, was observed. Maternal smoking and medical radiation during the first trimester were associated with the severe cloacal exstrophy phenotype. Compliance with periconceptional folic acid supplementation was associated with the mildest phenotype (epispadias).

CONCLUSIONS

Periconceptional folic acid supplementation appears to prevent the development of the severe phenotype of BEEC.

Bladder exstrophy: an epidemiologic study from the International Clearinghouse for Birth Defects Surveillance and Research, and an overview of the literature

Bladder exstrophy (BE) is a complex congenital anomaly characterized by a defect in the closure of the lower abdominal wall and bladder. We aimed to provide an overview of the literature and conduct an epidemiologic study to describe the prevalence, and maternal and case characteristics of BE. We used data from 22 participating member programs of the International Clearinghouse for Birth Defects Surveillance and Research (ICBDSR). All cases were reviewed and classified as isolated, syndrome, and multiple congenital anomalies. We estimated the total prevalence of BE and calculated the frequency and odds ratios for various maternal and case characteristics. A total of 546 cases with BE were identified among 26,355,094 births. The total prevalence of BE was 2.07 per 100,000 births (95% CI: 1.90-2.25) and varied between 0.52 and 4.63 among surveillance programs participating in the study. BE was nearly twice as common among male as among female cases. The proportion of isolated cases was 71%. Prevalence appeared to increase with increasing categories of maternal age, particularly among isolated cases. The total prevalence of BE showed some variations by geographical region, which is most likely attributable to differences in registration of cases. The higher total prevalence among male cases and older mothers, especially among isolated cases, warrants further attention.

Spectrum of cloacal exstrophy

Cloacal exstrophy, one of the most severe congenital anomalies compatible with life, occurs in up to 1 in 200,000 lives births. The condition affects nearly every major organ system with severe neurologic, skeletal, gastrointestinal, and genitourinary ramifications. With increased understanding of the anatomy and embryology combined with refinements in prenatal diagnosis and postnatal care, there is now near-universal survival of patients with cloacal exstrophy. Functional and cosmetic outcomes have improved with modifications in surgical technique. However, debate continues regarding the issue of gender identity, and long-term data are still accruing with respect to the best strategy for management. Despite the extensive malformations noted, many patients have gone on to live fruitful lives.

The role of osteotomy in surgical repair of bladder exstrophy

Classic bladder exstrophy (CBE) patients are born with a pubic diastasis that increases steadily with age from a mean value of 4 cm at birth to a mean of 8 cm at age 10, compared with a mean normal width of the pubic symphysis of 0.6 cm at all ages. The width of the sacrum and length of the posterior (iliac) segment of the pelvis in CBE patients are normal; however, the anterior (ischiopubic) segment of the pelvis is a mean 30% shorter and both the anterior and posterior segments are externally rotated compared to controls. The main role of osteotomy in treatment of CBE appears to be to relax tension on the bladder and repaired abdominal wall during wound-healing. Anterior innominate osteotomy with optional posterior vertical iliac osteotomy presents several advantages over the prior conventional technique of posterior iliac osteotomy. These include (a) less intraoperative blood loss, (b) better apposition and mobility of the pubic rami at the time of closure, (c) allowance for placement of an external fixator under direct vision, (d) allowance for secure external fixation in children over 6 months old, and (e) no requirement to turn the patient during the operation.

Comprehensive genetic analysis of OEIS complex reveals no evidence for a recurrent microdeletion or duplication

Omphalocele-exstrophy of the bladder-imperforate anus-spinal defects (OEIS) complex, or cloacal exstrophy (EC), is a rare constellation of malformations in humans involving the urogenital, gastrointestinal, and skeletal systems, and less commonly the central nervous system. Although OEIS complex is well-recognized in the clinical setting, there remains a significant lack of understanding of this condition at both the developmental and the genetic level. While most cases are sporadic, familial cases have been reported, suggesting that one or more specific genes may play a significant role in this condition. Several developmental mechanisms have been proposed to explain the etiology of OEIS complex, and it is generally considered to be a defect early in caudal mesoderm development and ventral body wall closure. The goal of this study was to identify genetic aberrations in 13 patients with OEIS/EC using a combination of candidate gene analysis and microarray studies. Analysis of 14 candidate genes in combination with either high resolution SNP or oligonucleotide microarray did not reveal any disease-causing mutations, although novel variants were identified in five patients. To our knowledge, this is the most comprehensive genetic analysis of patients with OEIS complex to date. We conclude that OEIS is a complex disorder from an etiological perspective, likely involving a combination of genetic and environmental predispositions. Based on our data, OEIS complex is unlikely to be caused by a recurrent chromosomal aberration.

Evidence for linkage of the bladder exstrophy-epispadias complex on chromosome 4q31.21-22 and 19q13.31-41 from a consanguineous Iranian family

BACKGROUND

The bladder exstrophy-epispadias complex (BEEC) is a spectrum of anomalies involving the abdominal wall, pelvis, urinary tract, genitalia, and, occasionally, the spine and anus. Although BEEC typically occurs sporadically, families with two or more affected members have been reported. The present authors previously conducted a genome-wide linkage analysis in two multiply affected (multiplex) families (one of German and one of Spanish origin), which revealed several chromosomal regions compatible with linkage. In the present study, genome-wide linkage analysis was performed in a recently reported consanguineous Iranian multiplex family with an affected sibling pair: a female with epispadias and a male with classic exstrophy of the bladder.

METHODS

The Affymetrix 250K Sty chip (238,304 single nucleotide polymorphisms) was used to genotype the parents and four children, including the two affected siblings. Parametric and nonparametric linkage analyses were performed.

RESULTS

Parametric linkage analysis under a recessive model with complete penetrance identified seven loci with LOD scores >1.6 (1p33, 4q31.21-22, 9q22.33, 12q13.13-2, 13q12.12-13, 18q23, and 19q13.31-41). These results were supported by nonparametric linkage analysis. Haplotype analysis showed that the affected individuals were homozygous identical by descent for all seven regions. Two of these regions overlapped with regions observed previously in the Spanish family -one on chromosome 4q31.21-22, and the other on chromosome 19q13.31-41.

CONCLUSION

These results suggest that chromosomal regions 4q31.21-22 and 19q13.31-41 are likely to harbor genes for an autosomal recessive form of BEEC.

Embryonic expression of the cysteine rich protein 61 (CYR61) gene: A candidate for the development of human epispadias

BACKGROUND

Isolated epispadias is the mildest phenotype of the exstrophy-epispadias complex, a urogenital birth defect of variable severity. The androgen receptor antagonist flutamide (FLU) is known to cause malformations in the rat genital and reproductive tract, and single-dose prenatal FLU exposure can induce epispadias in rat offspring. The Cyr61 gene exhibited the highest response to FLU in rat fetal testis, and we suggested it a promising candidate gene for epispadias in humans, because its protein product promotes proliferation, migration, and adhesion of endothelial cells and fibroblasts.

METHODS

We used whole mount in situ analysis in mice to investigate ventrocaudal expression of the Cyr61 transcript at gestational days 9.5 to 11.5, which is the equivalent of human gestational weeks 4 to 6 (postulated time of epispadias organogenesis in humans). We also performed mutational analysis of the CYR61 gene in 11 patients with isolated epispadias and in additional eight patients with the related classic bladder exstrophy phenotype.

RESULTS

Expression of Cyr61 was detected in endothelial cells of vessels surrounding the cloaca and the umbilical cord on gestational days 10 and 11.5. The mutation screening, however, revealed no alterations in the coding region of human CYR61.

CONCLUSIONS

The spatiotemporal expression pattern observed suggests a role for Cyr61 in the development of the external genitalia. Our mutation screening study, however, could not confirm that mutations affecting the CYR61 gene are a frequent cause of epispadias or classic bladder exstrophy, although rare mutations might be detectable in larger patient samples.

Cloacal exstrophy: a comprehensive review of an uncommon problem

OBJECTIVE

To provide a comprehensive overview of the clinical features, diagnosis, current management strategies, and outcomes of cloacal exstrophy.

METHODS

A PUBMED/Medline search of the literature was performed on cloacal exstrophy focusing on associated anomalies, treatment, and quality of life issues.

RESULTS

The incidence of cloacal exstrophy is between 1 in 200,000 and 400,000 live births. Survival rates now approach 100% secondary to improved understanding of underlying abnormalities and advances in neonatal care and surgical technique. Important principles of initial management include proper nutritional support, early closure of exstrophy, and preservation of intestinal length. The achievement of urinary and fecal continence remains a challenge. Data for long-term outcomes are now emerging which provide new insight into issues of gender identity, function, and psychosocial development of these patients.

CONCLUSION

Cloacal exstrophy remains a rare and complex congenital anomaly, characterized by an array of anatomical defects affecting multiple organ systems. A multidisciplinary approach to management is advocated with a focus on optimization of patient function and quality of life.

The exstrophy-epispadias complex

Exstrophy-epispadias complex (EEC) represents a spectrum of genitourinary malformations ranging in severity from epispadias (E) to classical bladder exstrophy (CEB) and exstrophy of the cloaca (EC). Depending on severity, EEC may involve the urinary system, musculoskeletal system, pelvis, pelvic floor, abdominal wall, genitalia, and sometimes the spine and anus. Prevalence at birth for the whole spectrum is reported at 1/10,000, ranging from 1/30,000 for CEB to 1/200,000 for EC, with an overall greater proportion of affected males. EEC is characterized by a visible defect of the lower abdominal wall, either with an evaginated bladder plate (CEB), or with an open urethral plate in males or a cleft in females (E). In CE, two exstrophied hemibladders, as well as omphalocele, an imperforate anus and spinal defects, can be seen after birth. EEC results from mechanical disruption or enlargement of the cloacal membrane; the timing of the rupture determines the severity of the malformation. The underlying cause remains unknown: both genetic and environmental factors are likely to play a role in the etiology of EEC. Diagnosis at birth is made on the basis of the clinical presentation but EEC may be detected prenatally by ultrasound from repeated non-visualization of a normally filled fetal bladder. Counseling should be provided to parents but, due to a favorable outcome, termination of the pregnancy is no longer recommended. Management is primarily surgical, with the main aims of obtaining secure abdominal wall closure, achieving urinary continence with preservation of renal function, and, finally, adequate cosmetic and functional genital reconstruction. Several methods for bladder reconstruction with creation of an outlet resistance during the newborn period are favored worldwide. Removal of the bladder template with complete urinary diversion to a rectal reservoir can be an alternative. After reconstructive surgery of the bladder, continence rates of about 80% are expected during childhood. Additional surgery might be needed to optimize bladder storage and emptying function. In cases of final reconstruction failure, urinary diversion should be undertaken. In puberty, genital and reproductive function are important issues. Psychosocial and psychosexual outcome depend on long-term multidisciplinary care to facilitate an adequate quality of life.

Bladder exstrophy–epispadias complex: Investigation of suppressor of variegation, enhancer of zeste and Trithorax (SET) as a candidate gene in a large cohort of patients

OBJECTIVE

The bladder exstrophy-epispadias complex (BEEC) describes a rare anterior midline defect with variable expression involving the infra-umbilical abdominal wall, including the pelvis, urinary tract and external genitalia. It is assumed that the underlying cause of BEEC is a multifactorial mode of inheritance; however, its aetiology remains unknown. Only a few BEEC patients with distinctive cytogenetic features such as numeric or structural chromosomal abnormalities have been reported. The observation of translocations concerning the region of chromosome 9q32-q34.1 in two patients implies that this region bears a candidate gene which, during early blastogenesis, governs the development of this primary field. In this context, we considered the suppressor of variegation, enhancer of zeste and Trithorax (SET) gene, located at chromosome 9q34, to be a good candidate, as the protein encoded is involved in the regulation of cell proliferation and differentiation. Moreover, SET expression was detected in embryonic kidney.

MATERIAL AND METHODS

A total of 33 patients affected with BEEC were analysed for mutations in the SET gene.

RESULTS

SET analysis did not reveal either a mutation or the presence of four single-nucleotide polymorphisms (dbSNP124) already described in the database.

CONCLUSIONS

The data obtained in this study most likely exclude the SET gene as a possible genetic cause of BEEC. Hence, other genes in this region may contribute to the development of this midline defect.

A case of female epispadias

OBJECTIVE

To present a case of unrecognized female epispadias.

DESIGN

Case report.

SETTING

University-based reproductive endocrinology and fertility clinic.

PATIENT(S)

A 16-year-old girl with epispadias, history of mild urinary incontinence, auditory neuropathy, and functional hyperandrogenism.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Peripheral blood array-based comparative genomic hybridization.

RESULT(S)

The patient was referred for evaluation of excessive weight gain, secondary amenorrhea, and abnormal external genitalia. Examination under anesthesia revealed bilateral labia minora hypertrophy, bifid clitoris, and a patulous urethra, consistent with female epispadias. Hormonal evaluation showed functional hyperandrogenism, and peripheral blood array-based comparative genomic hybridization showed no chromosomal deletions or duplications.

CONCLUSION(S)

Female epispadias is a rare abnormality, not commonly recognized by most practitioners. The diagnosis is supported by a history of urinary incontinence and physical findings of bifid clitoris and patulous urethra. The condition can have serious physical and psychological consequences leading to a gross disruption of social function.

Overview of bladder exstrophy: a third world perspective

INTRODUCTION

Bladder exstrophy is an uncommon condition, and the ramifications for patients living in a Third World environment are extensive.

PATIENTS AND METHODS

This was a retrospective study of 57 patients, managed between 1983 and 2006. The review looked at the home environment, clinical findings, treatment provided, and short-term outcome.

RESULTS

Of the 57 patients, 19 were born in metropolitan and 38 in rural hospitals. Twenty-four patients (42%) were referred on the first day of life, 21 (37%) within the first week, and 12 patients (21%) were older than 1 week of life. Associated congenital anomalies were seen in 18 patients (32%). Twelve patients died in hospital, the remaining 45 were discharged. Thirty three patients returned for review; their ages ranged from 2 to 17 years (median, 3 years). The overall mortality was 42%. On follow-up, urinary incontinence was the main complaint, which greatly affected the child's schooling and social life.

CONCLUSION

Bladder exstrophy is an uncommon condition. The associated congenital abnormalities together with the impoverished environment result in a poor prognosis. Antenatal screening, early referral, and establishing urinary continence are factors that will improve the outcome in children with this condition in a Third World environment.

Investigation of FGF10 as a candidate gene in patients with anorectal malformations and exstrophy of the cloaca

The spectrum of anorectal malformations (ARM) comprises anal stenosis, ectopic anus, recto-urogenital fistula, persistent cloaca, multisystem VACTERL (VATER associations including cardiac and limb anomalies) associations, and exstrophy of the cloaca (CE). The latter also constitutes the most severe form of the bladder exstrophy epispadias complex. Since recent data revealed that fibroblast growth factor 10 (fgf-10) invalidation in mice resulted in a genetically reproducible urorectal defect, we considered FGF10 a suitable candidate gene for ARM and CE, as the protein seems to be involved in the development of this primary developmental field. A total of 20 patients (ten with ARM and VACTERL association, respectively, and ten with CE) were analysed for genomic mutations in the coding regions and exon-intron boundaries of FGF10. Aside from a common FGF10 variant no deviation from the wild-type sequence could be detected and data obtained is not supportive of FGF10 as a genetic cause of ARMs or CE in the patients investigated. Nonetheless, mutations in possibly further upstream located promoter regions and/or unknown regulatory sequences or non-coding regions cannot be excluded. Furthermore, it cannot be ruled out that other genes involved in the signalling pathway of FGF10 may contribute to the formation of these congenital malformations.