Ventral body wall closure: Mechanistic insights from mouse models and translation to human pathology

The ventral body wall (VBW) that encloses the thoracic and abdominal cavities arises by extensive cell movements and morphogenetic changes during embryonic development. These morphogenetic processes include embryonic folding generating the primary body wall; the initial ventral cover of the embryo, followed by directed mesodermal cell migrations, contributing to the secondary body wall. Clinical anomalies in VBW development affect approximately 1 in 3000 live births. However, the cell interactions and critical cellular behaviors that control VBW development remain little understood. Here, we describe the embryonic origins of the VBW, the cellular and morphogenetic processes, and key genes, that are essential for VBW development. We also provide a clinical overview of VBW anomalies, together with environmental and genetic influences, and discuss the insight gained from over 70 mouse models that exhibit VBW defects, and their relevance, with respect to human pathology. In doing so we propose a phenotypic framework for researchers in the field which takes into account the clinical picture. We also highlight cases where there is a current paucity of mouse models for particular clinical defects and key gaps in knowledge about embryonic VBW development that need to be addressed to further understand mechanisms of human VBW pathologies.

A Child With Diphallia, Duplicate Bladder, Bladder Exstrophy, and Anorectal Malformation

Congenital true diphallia, complete duplicate bladder, bladder exstrophy, and anorectal malformation in a child are uncommon. Here, we present the case of a 3-year-old boy with multiple genitourinary malformation, including true diphallia, complete duplicate bladder, bladder exstrophy, epispadias, and anorectal malformation. Multi-departmental collaborative treatment for complex conditions ultimately achieved an ideal appearance for this patient. All vital signs were stable after the surgery and they remained consistent during follow-up. In such cases, surgical correction is individualized to achieve adequate urinary continence and erection with adequate esthetics.

A Multicountry Analysis of Prevalence and Mortality among Neonates and Children with Bladder Exstrophy

OBJECTIVE

Bladder exstrophy (BE) is a rare but severe birth defect affecting the lower abdominal wall and genitourinary system. The objective of the study is to examine the total prevalence, trends in prevalence, and age-specific mortality among individuals with BE.

STUDY DESIGN

We conducted a retrospective cohort study. Data were analyzed from 20 birth defects surveillance programs, members of the International Clearinghouse for Birth Defects Surveillance and Research in 16 countries. Live births, stillbirths, and elective terminations of pregnancy for fetal anomaly (ETOPFA) diagnosed with BE from 1974 to 2014. Pooled and program-specific prevalence of BE per 100,000 total births was calculated. The 95% confidence intervals (CI) for prevalence were estimated using Poisson approximation of binomial distribution. Time trends in prevalence of BE from 2000 to 2014 were examined using Poisson regression. Proportion of deaths among BE cases was calculated on the day of birth, day 2 to 6, day 7 to 27, day 28 to 364, 1 to 4 years, and ≥5 years. Mortality analysis was stratified by isolated, multiple, and syndromic case status.

RESULTS

The pooled total prevalence of BE was 2.58 per 100,000 total births (95% CI = 2.40, 2.78) for study years 1974 to 2014. Prevalence varied over time with a decreasing trend from 2000 to 2014. The first-week mortality proportion was 3.5, 17.3, and 14.6% among isolated, multiple, and syndromic BE cases, respectively. The majority of first-week mortality occurred on the first day of life among isolated, multiple, and syndromic BE cases. The proportion of first-week deaths was higher among cases reported from programs in Latin America where ETOPFA services were not available.

CONCLUSION

Prevalence of BE varied by program and showed a decreasing trend from 2000 to -2014. Mortality is a concern among multiple and syndromic cases, and a high proportion of deaths among cases occurred during the first week of life.

KEY POINTS

· Total prevalence of BE was 2.58 per 100,000 births.. · Prevalence decreased from 2000 to 2014.. · The first-week mortality was 9.3%..

Palliative Care for Pediatric Urology

Palliative care in the field of urology has largely been limited to adult oncologic conditions. Although there is a plethora of established literature suggesting the advantageous impact of palliative care, there is limited integration of palliative care in adult urology. This underutilization is further exacerbated in pediatric urology, and palliative care in pediatric urology remains an underexplored area despite the prevalence of several life-limiting conditions in this patient population. This paper highlights the potential need for palliative care intervention in a variety of urologic conditions in the pediatric population, including congenital lower urinary tract obstruction, neurogenic bladder dysfunction, exstrophy-epispadias complex, and congenital bilateral renal agenesis. Each condition poses unique challenges that can be addressed with the inclusion of a palliative care team, including decision-making spanning prenatal-neonatal-pediatric periods, acute and chronic symptom management, family relations, body image issues, risk of recurrent hospitalizations and surgeries, and potentially fatal complications. Alongside standard urologic interventions, palliative care can serve as an additional means of addressing physical and psychosocial symptoms experienced by pediatric urology patients to enhance the quality of life of patients and their families.

Ensuring our exstrophy-epispadias complex patients and families thrive

Individuals with bladder exstrophy-epispadias complex (EEC) need long-term integrated medical/surgical and psychosocial care. These individuals are at risk for medical and surgical complications and experience social and psychological obstacles related to their genitourinary anomaly. This care needs to be accessible, comprehensive, and coordinated. Multiple surgical interventions, reoccurring hospitalizations, urinary and fecal incontinence, extensive treatment regimens for continent diversions, genital differences, and sexual health implications affect the quality of life for the EEC patient. Interventions must include psychosocial support, medical literacy initiatives, behavioral health services, school and educational consultation, peer-to-peer opportunities, referrals to disease-specific camps, mitigation of adverse childhood events (ACEs), formal transition of care to adult providers, family and teen advisory opportunities, and clinical care coordination. The priority of long-term kidney health will necessitate strong collaboration among urology and nephrology teams. Given the rarity of these conditions, multi-center and global efforts are paramount in the trajectory of improving care for the EEC population. To achieve the highest standards of care and ensure that individuals with EEC can thrive in their environment, multidisciplinary and integrated medical/surgical and psychosocial services are imperative.

Exome Survey and Candidate Gene Re-Sequencing Identifies Novel Exstrophy Candidate Genes and Implicates LZTR1 in Disease Formation

BACKGROUND

The bladder exstrophy-epispadias complex (BEEC) is a spectrum of congenital abnormalities that involves the abdominal wall, the bony pelvis, the urinary tract, the external genitalia, and, in severe cases, the gastrointestinal tract as well.

METHODS

Herein, we performed an exome analysis of case-parent trios with cloacal exstrophy (CE), the most severe form of the BEEC. Furthermore, we surveyed the exome of a sib-pair presenting with classic bladder exstrophy (CBE) and epispadias (E) only. Moreover, we performed large-scale re-sequencing of CBE individuals for novel candidate genes that were derived from the current exome analysis, as well as for previously reported candidate genes within the CBE phenocritical region, 22q11.2.

RESULTS

The exome survey in the CE case-parent trios identified two candidate genes harboring de novo variants (NR1H2, GKAP1), four candidate genes with autosomal-recessive biallelic variants (AKR1B10, CLSTN3, NDST4, PLEKHB1) and one candidate gene with suggestive uniparental disomy (SVEP1). However, re-sequencing did not identify any additional variant carriers in these candidate genes. Analysis of the affected sib-pair revealed no candidate gene. Re-sequencing of the genes within the 22q11.2 CBE phenocritical region identified two highly conserved frameshift variants that led to early termination in two independent CBE males, in LZTR1 (c.978_985del, p.Ser327fster6) and in SLC7A4 (c.1087delC, p.Arg363fster68).

CONCLUSIONS

According to previous studies, our study further implicates LZTR1 in CBE formation. Exome analysis-derived candidate genes from CE individuals may not represent a frequent indicator for other BEEC phenotypes and warrant molecular analysis before their involvement in disease formation can be assumed.

Recurrent giant neobladder calculus extrusion after bladder exstrophy repair

Introduction

Patients with bladder exstrophy subjected to reconstructive surgeries are at risk of developing urinary calculus.

Case presentation

We report the case of a 29-year-old male patient with bladder exstrophy who presented with a recurrent episode of extrusion of calculus through the neobladder and anterior abdominal wall. Calculus removal and reconstructive repair of the neobladder and abdominal wall were performed in 2010. Nine years following the procedure, the patient returned with new large neobladder calculus extrusion.

Conclusion

Recurrence of large calculus should be seen as the new paradigm for the importance of close follow-up in bladder exstrophy patients.

Body contouring abdominoplasty for augmentation enterocystoplasty with continent cutaneous urinary diversion in an obese adolescent patient: A case report

Bladder exstrophy requires staged reconstruction to achieve control over bladder function. In case of failure, bladder neck closure with augmentation enterocystoplasty and appendicovesicostomy is a good surgical option. We report the case of a girl born with bladder exstrophy who, despite multiple surgical reconstructions in childhood, developed severe stress incontinence with contracted bladder and recurrent urinary tract infections during adolescence. The patient had a large abdominal pannus and in order to realize the appendicovesicostomy, we combined this intervention with a body contouring abdominoplasty to achieve tension free closure.

Urinary and fecal continence in adolescent and adult patients with cloacal exstrophy

OBJECTIVE

To evaluate the prevalence of urinary (UI) and fecal incontinence (FI) and the incontinence-related quality of life (QoL) in adolescent and adult patients with cloacal exstrophy (CE) in Germany.

MATERIALS AND METHODS

CE-patients of a tertiary care center and the German support group for anorectal malformations (SoMA e.V.) were included (October 2015 until September 2020). Data were assessed using a composed questionnaire consisting of 18 self-generated questions and two validated German questionnaires (King's health questionnaire (KHQ), Questionnaire on Quality of Life in Fecal Incontinence (FLQAI)).

RESULTS

Out of 23 included patients, 19 had continent and 3 incontinent urinary diversions (UD), 1 was unspecified; 2/23 were on dialysis. 73.7% (14/19) had undergone bladder augmentation, 4/19 had a pouch, 1/19 a neobladder. 94.7% (18/19) had a continent cutaneous channel and performed intermittent self-catheterization. UI was common (71.4%, 15/21). Neither the UD nor the involuntary loss of urine itself had a significant impact on QoL. Comparing the KHQ results, UI-related QoL of CE-patients was significantly lower than in a published reference group. 78.3% (18/23) had a bowel stoma. 34.8% (8/23) reported involuntary stool-soiling. Neither the way of bowel-emptying nor involuntary stool-soiling itself showed significant influence on FI-related QoL in the FLQAI. FLQAI items showed significant differences only for one of two published reference groups.

CONCLUSIONS

Long-term incontinence rates in adolescent and adult CE-patients are high. Incontinence-related QoL was reduced compared to published reference groups but was minimally influenced by incontinence itself, the type of UD or the way of bowel-emptying, respectively.

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.

Exstrophy-Epispadias Complex Variants: A Hybrid Case

The term exstrophy-epispadias complex refers to a group of midline defects ranging from epispadias to cloacal exstrophy. Bladder exstrophy is the most frequent malformation of this spectrum and it can present as a classical or a variant form. We report a case of a hybrid bladder exstrophy variant having some characteristics of both a duplicate bladder exstrophy and a superior vesical fistula.

Bladder exstrophy with exstrophic rectal duplication in an infant: An extremely rare case

Exstrophic rectal duplication and its association with bladder exstrophy and anorectal malformation is an extremely rare clinical entity. This is a report of the second case of an exstrophic rectal duplication associated with bladder exstrophy in English literature. However, it is the first case, where all these anomalies were accompanied by an anorectal malformation.

New Insights on the Basic Science of Bladder Exstrophy-epispadias Complex

The exstrophy-epispadias complex is a rare congenital anomaly presenting as a wide spectrum of disorders. The complex nature of this malformation leads to continuous investigations of the basic science concepts behind it. Elucidating these concepts allows one to fully understand the mechanisms behind the disease in order to improve diagnosis, management, and treatment ultimately leading to improvement in patient quality of life. Multiple technological advancements within the last 10 years have been made allowing for new studies to be conducted. Herein, the authors conduct a literature review of studies from 2009 to 2019, considering novel theories regarding the genetics, embryology, bladder, bony pelvis, prostate, and genitalia of patients with bladder exstrophy-epispadias complex.

Repeated successful vaginal delivery in a pregnant woman with unrepaired ectopia vesicae and split pelvis: a case study

Abstract

Ectopia vesicae, or bladder exstrophy, is a rare malformation, more frequently found in males. Very few cases of pregnancy with unrepaired ectopia vesicae have been reported in literature. The majority of these pregnant women with ectopia vesicae have terminated their pregnancies by cesarean section due to malpresentation, preterm labor or other indications. Clemetson concluded that cesarean section was the preferable method of term delivery to avoid postpartum prolapse. We have a different opinion on this because we had an interesting case. A woman with unrepaired ectopia vesicae had two successful vaginal deliveries, in 2009 and 2019 respectively. She recovered well and did not have any symptoms or signs of pelvic organ prolapse (POP) so far.

Case presentation

Let us present this woman with ectopia vesicae who had four pregnancies; two spontaneous abortions and two vaginal deliveries. In 2009, she had a successful vaginal delivery at Yantai Harbor Hospital where the first author worked at that time. She met the first author again surprisingly, during her third trimester in 2019. She had a spacious pelvis and pendulous abdomen. In this fourth pregnancy, the fetus changed its presentation frequently. Still, she had the second vaginal delivery successfully. She recovered fully after delivery and did not have any symptoms or signs of POP. As far as we know, this is the first case that a patient with ectopia vesicae who has been observed for such a long time after multiple vaginal deliveries.

Conclusions

Doctors must evaluate the risk of vaginal delivery or cesarean section and consider maternal-neonatal health. Prior to this, women with repaired or unrepaired ectopia vesicae usually delivered their babies by cesarean section. Our practice shows that vaginal delivery is also a safe and feasible choice for some of these patients, especially for those with unrepaired, mild types of ectopia vesicae who experience no other dangerous or uncomfortable symptoms.

Experiencia en el abordaje de pacientes con complejo extrofia-epispadias en un centro de alto nivel de complejidad en Colombia, 10 años

Objetivos El complejo extrofia-epispadias (CEE) se considera una de las malformaciones más severas de la línea media de compromiso multisistémico. La extrofia vesical es la presentación más frecuente en el espectro del complejo. Esta patología tiene un alto impacto en la calidad de vida. A pesar de la relación entre un cierre primario temprano y mejores resultados, en nuestro medio la remisión es tardía y la experiencia es escasa. El objetivo del siguiente estudio es mostrar la experiencia en el abordaje de CEE en los últimos 10 años en una institución de alto nivel de complejidad y remisión en Colombia.

Materiales y métodos Se realiza un estudio observacional descriptivo, con una serie de casos del 2006 al 2016.

Resultados En 10 años, se presentaron 5 casos de CEE en un centro de alta complejidad y remisión en Colombia. La mayoría de los pacientes han tenido múltiples intervenciones; la edad del primer procedimiento fue 829 días en promedio (27,6 meses). Se ha tenido un seguimiento postoperatorio promedio de 2,8 años. No se han presentado neoplasias en el seguimiento. Las comorbilidades más frecuentes son infección y litiasis. Ninguno de los pacientes contactados reportó inicio de vida sexual. La escala International Consultation on Incontinence Questionnaire-Urinary Incontinence-Short Form (ICIQ-UI-SF) tuvo un promedio de 9 puntos. Existen factores sociales asociados en nuestro medio.

Conclusión El CEE requiere un abordaje temprano y multidisciplinario en instituciones con experiencia; los resultados en continencia urinaria, función sexual, desarrollo psicosocial y calidad de vida están sujetos a tratamiento oportuno de la patología.

Role of the LF-SINE-Derived Distal ISL1 Enhancer in Patients with Classic Bladder Exstrophy

A genome-wide association study and meta-analysis identified ISL1 as the first genome-wide significant susceptibility gene for classic bladder exstrophy (CBE). A short interspersed repetitive element (SINE), first detected in lobe-finned fishes (LF-SINE), was shown to drive Isl1 expression in embryonic mouse genital eminence. Hence, we assumed this enhancer a conclusive target for mutations associated with CBE formation and analyzed a cohort of 200 CBE patients. Although we identified two enhancer variants in five CBE patients, their clinical significance seems unlikely, implying that sequence variants in the ISL1 LF-SINE enhancer are not frequently associated with CBE.

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.

Genetic analysis of the role of Alx4 in the coordination of lower body and external genitalia formation

Although several syndromes include abnormalities of both the ventral body wall and external genitalia, the developmental bases of this correlation are largely unknown. Naturally occurring mutations in Aristaless-like 4 (Alx4, Strong's luxoid: Alx4^Lst) have ventral body wall and pelvic girdle abnormalities. We sought to determine whether the development of the genital tubercle (GT) and its derivatives, the external genitalia, is affected by this mutation. We thus performed genetic and tissue labeling analyses in mutant mice. Alx4^Lst/Lst mutants displayed hypoplasia of the dorsal GT and reduced expression of Fibronectin. We analyzed cell migration during GT formation by tissue labeling experiments and discovered that the cells located in the proximal segment of the umbilical cord (infra-umbilical mesenchyme) migrate toward the dorsal part of the GT. The Alx4^Lst/Lst mutants also displayed augmented expression of Hh signal-related genes. Hence, we analyzed a series of combinatorial mutants for Alx4, Sonic hedgehog (Shh) and GLI-Kruppel family member 3 (Gli3). These phenotype–genotype analyses suggested a genetic interaction between Alx4 and Hh signaling during GT formation. Moreover, Hh gain-of-function mutants phenocopied some of these phenotypes. These observations reveal novel information regarding the pathogenic mechanisms of syndromic lower ventral body malformations, which are largely unknown.

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.

Lower urinary tract development and disease

Congenital anomalies of the lower urinary tract (CALUT) are a family of birth defects of the ureter, the bladder, and the urethra. CALUT includes ureteral anomaliesc such as congenital abnormalities of the ureteropelvic junction (UPJ) and ureterovesical junction (UVJ), and birth defects of the bladder and the urethra such as bladder-exstrophy-epispadias complex (BEEC), prune belly syndrome (PBS), and posterior urethral valves (PUVs). CALUT is one of the most common birth defects and is often associated with antenatal hydronephrosis, vesicoureteral reflux (VUR), urinary tract obstruction, urinary tract infections (UTI), chronic kidney disease, and renal failure in children. Here, we discuss the current genetic and molecular knowledge about lower urinary tract development and genetic basis of CALUT in both human and mouse models. We provide an overview of the developmental processes leading to the formation of the ureter, the bladder, and the urethra, and different genes and signaling pathways controlling these developmental processes. Human genetic disorders that affect the ureter, the bladder and the urethra and associated gene mutations are also presented. As we are entering the postgenomic era of personalized medicine, information in this article may provide useful interpretation for the genetic and genomic test results collected from patients with lower urinary tract birth defects. With evidence-based interpretations, clinicians may provide more effective personalized therapies to patients and genetic counseling for their families.

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.

Isolated bladder exstrophy associated with a de novo 0.9 Mb microduplication on chromosome 19p13.12

BACKGROUND

The exstrophy-epispadias complex (BEEC) is a urogenital birth defect of varying severity. The causes of the BEEC are likely to be heterogeneous, with individual environmental or genetic risk factors still being largely unknown. In this study, we aimed to identify de novo causative copy number variations (CNVs) that contribute to the BEEC.

METHODS

Array-based molecular karyotyping was performed to screen 110 individuals with BEEC. Promising CNVs were tested for de novo occurrence by investigating parental DNAs. Genes located in regions of rearrangements were prioritized through expression analysis in mice to be sequenced in the complete cohort, to identify high-penetrance mutations involving small sequence changes.

RESULTS

A de novo 0.9 Mb microduplication involving chromosomal region 19p13.12 was identified in a single patient. This region harbors 20 validated RefSeq genes, and in situ hybridization data showed specific expression of the Wiz gene in regions surrounding the cloaca and the rectum between GD 9.5 and 13.5. Sanger sequencing of the complete cohort did not reveal any pathogenic alterations affecting the coding region of WIZ.

CONCLUSIONS

The present study suggests chromosomal region 19p13.12 as possibly involved in the development of CBE, but further studies are needed to prove a causal relation. The spatiotemporal expression patterns determined for the genes encompassed suggest a role for Wiz in the development of the phenotype. Our mutation screening, however, could not confirm that WIZ mutations are a frequent cause of CBE, although rare mutations might be detectable in larger patient samples. 19p13.12, microduplication, bladder exstrophy-epispadias complex, array-based molecular karyotyping, in situ hybridization analysis, copy number variations, WIZ gene.

Congenital renal anomalies in patients with classic bladder exstrophy

OBJECTIVE

To determine the proportion and type of renal anomalies that occur in children born with classic bladder exstrophy.

MATERIAL AND METHODS

All patients in a database of 1044 patients with the bladder exstrophy-epispadias-cloacal exstrophy complex were reviewed. Those with classic bladder exstrophy had their complete medical records reviewed and children with radiographic evidence of congenital renal anomalies were identified and characterized.

RESULTS

A total of 674 patients were identified with classic bladder exstrophy, of whom 462 had renal ultrasounds at the authors' institution. In this population, 13/462 (2.8%) had concomitant renal anomalies. The most common malformation was a duplicated collecting system in 6 patients. Hypoplastic or absent kidneys were present in 3 patients, pelvic kidney in 2, ureteropelvic junction obstruction in 1, and multicystic dysplastic kidney in 1 patient.

CONCLUSION

Isolated renal anomalies occur at a rate of 2.8% in children born with classic bladder exstrophy. Although uncommon in this rare birth defect, anatomic understanding of the entire genitourinary system is critical for operative planning and long-term follow-up of patients with bladder exstrophy.

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.

Genetic analysis of Hedgehog signaling in ventral body wall development and the onset of omphalocele formation

Background

An omphalocele is one of the major ventral body wall malformations and is characterized by abnormally herniated viscera from the body trunk. It has been frequently found to be associated with other structural malformations, such as genitourinary malformations and digit abnormalities. In spite of its clinical importance, the etiology of omphalocele formation is still controversial. Hedgehog (Hh) signaling is one of the essential growth factor signaling pathways involved in the formation of the limbs and urogenital system. However, the relationship between Hh signaling and ventral body wall formation remains unclear.

Methodology/Principal Findings

To gain insight into the roles of Hh signaling in ventral body wall formation and its malformation, we analyzed phenotypes of mouse mutants of Sonic hedgehog (Shh), GLI-Kruppel family member 3 (Gli3) and Aristaless-like homeobox 4 (Alx4). Introduction of additional Alx4^Lst mutations into the Gli3^Xt/Xt background resulted in various degrees of severe omphalocele and pubic diastasis. In addition, loss of a single Shh allele restored the omphalocele and pubic symphysis of Gli3^Xt/+; Alx4^Lst/Lst embryos. We also observed ectopic Hh activity in the ventral body wall region of Gli3^Xt/Xt embryos. Moreover, tamoxifen-inducible gain-of-function experiments to induce ectopic Hh signaling revealed Hh signal dose-dependent formation of omphaloceles.

Conclusions/Significance

We suggest that one of the possible causes of omphalocele and pubic diastasis is ectopically-induced Hh signaling. To our knowledge, this would be the first demonstration of the involvement of Hh signaling in ventral body wall malformation and the genetic rescue of omphalocele phenotypes.

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.

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.