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

Rare exonic CELSR3 variants identified in Bladder Exstrophy Epispadias Complex

Introduction/background

Bladder exstrophy epispadias complex (BEEC) is a rare congenital anomaly of unknown etiology, although, genetic and environmental factors have been associated with its development. Variants in several genes expressed in the urogenital pathway have been reported as causative for bladder exstrophy in human and murine models. The expansion of next-generation sequencing and molecular genomics has improved our ability to identify the underlying genetic causes of similarly complex diseases and could thus assist with the investigation of the molecular basis of BEEC.

Objective

The objective was to identify the presence of rare heterozygous variants in genes previously implicated in bladder exstrophy and correlate them with the presence or absence of bladder regeneration in our study population.

Patients and Methods

We present a case series of 12 patients with BEEC who had bladder biopsies performed by pediatric urology during bladder neck reconstruction or bladder augmentation. Cases were classified as "sufficient" or "insufficient" (n = 5 and 7, respectively) based on a bladder volume of greater than or less than 40% of expected bladder size. Control bladder tissue specimens were obtained from patients (n = 6) undergoing biopsies for conditions other than bladder exstrophy. Whole exome sequencing was performed on DNA isolated from the bladder specimens. Based on the hypothesis of de novo mutations, as well as the potential implications of autosomal dominant conditions with incomplete penetrance, each case was evaluated for autosomal dominant variants in a set of genes previously implicated in BEEC.

Results

Our review of the literature identified 44 genes that have been implicated in human models of bladder exstrophy. Our whole exome sequencing data analysis identified rare variants in two of these genes among the cases classified as sufficient, and seven variants in five of these genes among the cases classified as insufficient.

Conclusion

We identified rare variants in seven previously implicated genes in our BEEC specimens. Additional research is needed to further understand the cellular signaling underlying this potentially genetically heterogeneous embryological condition.

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.

Bi-allelic variants in CELSR3 are implicated in central nervous system and urinary tract anomalies

CELSR3 codes for a planar cell polarity protein. We describe twelve affected individuals from eleven independent families with bi-allelic variants in CELSR3. Affected individuals presented with an overlapping phenotypic spectrum comprising central nervous system (CNS) anomalies (7/12), combined CNS anomalies and congenital anomalies of the kidneys and urinary tract (CAKUT) (3/12) and CAKUT only (2/12). Computational simulation of the 3D protein structure suggests the position of the identified variants to be implicated in penetrance and phenotype expression. CELSR3 immunolocalization in human embryonic urinary tract and transient suppression and rescue experiments of Celsr3 in fluorescent zebrafish reporter lines further support an embryonic role of CELSR3 in CNS and urinary tract formation.

Slc20a1 and Slc20a2 regulate neuronal plasticity and cognition independently of their phosphate transport ability

In recent years, primary familial brain calcification (PFBC), a rare neurological disease characterized by a wide spectrum of cognitive disorders, has been associated to mutations in the sodium (Na)-Phosphate (Pi) co-transporter SLC20A2. However, the functional roles of the Na-Pi co-transporters in the brain remain still largely elusive. Here we show that Slc20a1 (PiT-1) and Slc20a2 (PiT-2) are the most abundant Na-Pi co-transporters expressed in the brain and are involved in the control of hippocampal-dependent learning and memory. We reveal that Slc20a1 and Slc20a2 are differentially distributed in the hippocampus and associated with independent gene clusters, suggesting that they influence cognition by different mechanisms. Accordingly, using a combination of molecular, electrophysiological and behavioral analyses, we show that while PiT-2 favors hippocampal neuronal branching and survival, PiT-1 promotes synaptic plasticity. The latter relies on a likely Otoferlin-dependent regulation of synaptic vesicle trafficking, which impacts the GABAergic system. These results provide the first demonstration that Na-Pi co-transporters play key albeit distinct roles in the hippocampus pertaining to the control of neuronal plasticity and cognition. These findings could provide the foundation for the development of novel effective therapies for PFBC and cognitive disorders.

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.

Case report: Duplicated appendicitis with history of cloacal exstrophy causing bowel obstruction

INTRODUCTION

Cloacal and bladder exstrophy are rare embryological defects that can cause developmental disruption of surrounding organ structures, the pelvis, spinal cord, and small intestines being the most commonly affected. Duplicated appendix is another rare embryological defect that has historically caused confusing clinical presentations. Our case highlights a rare instance of a patient with cloacal exstrophy who presented with a bowel obstruction and an associated inflamed duplicated appendix.

CASE PRESENTATION

A newborn male is born with omphalocele-exstrophy-imperforate anus-spinal defects (OEIS) complex. As primary surgical reconstruction was pursued, the patient was found to have a non-inflamed duplicated appendix, which was left unremoved. In the following months, the patient experienced episodes of small bowel obstruction, eventually requiring surgical intervention. During this operation, the duplicated appendix was noted to be inflamed, prompting removal of both appendices.

DISCUSSION

This case highlights the increased prevalence of duplicated appendix in a patient with cloacal exstrophy, as well as the utility of prophylactic appendectomy for patients incidentally found to have a duplicated appendix intraoperatively. The duplicated appendix may lead to increased rates of complications and atypical presentation of appendicitis, supporting the practice of prophylactic appendectomy in patients with an incidentally found duplicated appendix.

CONCLUSION

We suggest clinicians be aware of the association and potentially atypical presentation of appendicitis in patients with a duplicated appendix, particularly in the setting of cloacal exstrophy. The decision to prophylactically remove an incidentally found, non-inflamed duplicated appendix may be beneficial in preventing confusing clinical presentations and future complications.

Modelling human lower urinary tract malformations in zebrafish

Advances in molecular biology are improving our understanding of the genetic causes underlying human congenital lower urinary tract (i.e., bladder and urethral) malformations. This has recently led to the identification of the first disease-causing variants in the gene BNC2 for isolated lower urinary tract anatomical obstruction (LUTO), and of WNT3 and SLC20A1 as genes implicated in the pathogenesis of the group of conditions called bladder-exstrophy-epispadias complex (BEEC). Implicating candidate genes from human genetic data requires evidence of their influence on lower urinary tract development and evidence of the found genetic variants' pathogenicity. The zebrafish (Danio rerio) has many advantages for use as a vertebrate model organism for the lower urinary tract. Rapid reproduction with numerous offspring, comparable anatomical kidney and lower urinary tract homology, and easy genetic manipulability by Morpholino®-based knockdown or CRISPR/Cas editing are among its advantages. In addition, established marker staining for well-known molecules involved in urinary tract development using whole-mount in situ hybridization (WISH) and the usage of transgenic lines expressing fluorescent protein under a tissue-specific promoter allow easy visualization of phenotypic abnormalities of genetically modified zebrafish. Assays to examine the functionality of the excretory organs can also be modeled in vivo with the zebrafish. The approach of using these multiple techniques in zebrafish not only enables rapid and efficient investigation of candidate genes for lower urinary tract malformations derived from human data, but also cautiously allows transferability of causality from a non-mammalian vertebrate to humans.

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

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

Exome sequencing of child-parent trios with bladder exstrophy: Findings in 26 children

Bladder exstrophy (BE) is a rare, lower ventral midline defect with the bladder and part of the urethra exposed. The etiology of BE is unknown but thought to be influenced by genetic variation with more recent studies suggesting a role for rare variants. As such, we conducted paired-end exome sequencing in 26 child/mother/father trios. Three children had rare (allele frequency ≤ 0.0001 in several public databases) inherited variants in TSPAN4, one with a loss-of-function variant and two with missense variants. Two children had loss-of-function variants in TUBE1. Four children had rare missense or nonsense variants (one per child) in WNT3, CRKL, MYH9, or LZTR1, genes previously associated with BE. We detected 17 de novo missense variants in 13 children and three de novo loss-of-function variants (AKR1C2, PRRX1, PPM1D) in three children (one per child). We also detected rare compound heterozygous loss-of-function variants in PLCH2 and CLEC4M and rare inherited missense or loss-of-function variants in additional genes applying autosomal recessive (three genes) and X-linked recessive inheritance models (13 genes). Variants in two genes identified may implicate disruption in cell migration (TUBE1) and adhesion (TSPAN4) processes, mechanisms proposed for BE, and provide additional evidence for rare variants in the development of this defect.

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.

Association of ISL1 polymorphisms and eosinophilic levels among otitis media patients

Background

Otitis media (OM) is a middle ear inflammatory complex disorder involving genetic and environmental factors. It onsets during childhood and often recurs and perplexes in genetically susceptible patients. Previously, murine models had shown the association of ISL LIM homeobox 1 (ISL1) gene with otitis media with effusion.

Aim

To investigate the association of ISL1 genetic variants with otitis media.

Subjects and methods

A total of 285 cases and 277 controls were recruited for the study. The entire coding region of ISL1 gene was genotyped using Sanger sequencing or single‐strand conformation polymorphism methods. Genotype, haplotype, in silico analysis, and linkage disequilibrium analysis were performed.

Results

The variants rs2303751 (c.504A>G) and rs121913540 (c.513G>A) were associated with OM, and the OR (95%CI) was 0.74 (0.57–0.95) and 0.43 (0.20–0.91), respectively. Besides, the rs2303751 AA genotype was associated with elevated eosinophil numbers in OM when compared to controls. The 5 SNP haplotype analysis of SNPs c.‐492A>G, c.504A>G, c.513G>A, c.576C>T, and c.*651A>T revealed A‐A‐G‐C‐A to be a risk haplotype in females whereas the 3 SNP haplotype analysis of SNPs c.504A>G, c.513G>A, and c.567C>T suggested G‐A‐C as protective and A‐G‐C to be a risk haplotype for otitis media.

Conclusion

Ours is the first report which shows a significant association of ISL1 variants (rs2303751 and rs121913540) with hearing‐related disorder like otitis media in humans. These results implicate the possible role of ISL1 gene in the etiopathology of otitis media. The replication of the study in other ethnic populations may strengthen our findings.

SLC20A1 Is Involved in Urinary Tract and Urorectal Development

Previous studies in developing Xenopus and zebrafish reported that the phosphate transporter slc20a1a is expressed in pronephric kidneys. The recent identification of SLC20A1 as a monoallelic candidate gene for cloacal exstrophy further suggests its involvement in the urinary tract and urorectal development. However, little is known of the functional role of SLC20A1 in urinary tract development. Here, we investigated this using morpholino oligonucleotide knockdown of the zebrafish ortholog slc20a1a. This caused kidney cysts and malformations of the cloaca. Moreover, in morphants we demonstrated dysfunctional voiding and hindgut opening defects mimicking imperforate anus in human cloacal exstrophy. Furthermore, we performed immunohistochemistry of an unaffected 6-week-old human embryo and detected SLC20A1 in the urinary tract and the abdominal midline, structures implicated in the pathogenesis of cloacal exstrophy. Additionally, we resequenced SLC20A1 in 690 individuals with bladder exstrophy-epispadias complex (BEEC) including 84 individuals with cloacal exstrophy. We identified two additional monoallelic de novo variants. One was identified in a case-parent trio with classic bladder exstrophy, and one additional novel de novo variant was detected in an affected mother who transmitted this variant to her affected son. To study the potential cellular impact of SLC20A1 variants, we expressed them in HEK293 cells. Here, phosphate transport was not compromised, suggesting that it is not a disease mechanism. However, there was a tendency for lower levels of cleaved caspase-3, perhaps implicating apoptosis pathways in the disease. Our results suggest SLC20A1 is involved in urinary tract and urorectal development and implicate SLC20A1 as a disease-gene for BEEC.

Variants in ALX4 and their association with genitourinary defects

BACKGROUND

Genitourinary anomalies occur in approximately 1% of humans, but in most cases, the cause is unknown. Aristaless-like homeobox 4 (ALX4) is an important homeodomain transcription factor. ALX4 mutations in humans and mouse have been associated with craniofacial defects and genitourinary anomalies such as cryptorchidism and epispadias.

OBJECTIVES

To investigate the presence and the functional impact of ALX4 variants in patients with genitourinary defects.

MATERIALS AND METHODS

Two separate patient cohorts were analyzed. One includes clinical exome-sequencing (ES) data from 7500 individuals. The other includes 52 ALX4 Sanger-sequenced individuals with bladder exstrophy-epispadias complex (BEEC). Dual luciferase assays were conducted to investigate the functional transcriptional impact of ALX4 variants in HeLa cells and HEK293 cells.

RESULTS

A total of 41 distinct ALX4 heterozygous missense variants were identified in the ES cohort with 15 variants present as recurrent in multiple patients. p.G369E and p.L373F were the only two present in individuals with genitourinary defects. A p.L373F heterozygous variant was also identified in one of the 52 individuals in the BEEC cohort. p.L373F and p.G369E were tested in vitro as both are considered damaging by MutationTaster, although only p.G369E was considered damaging by PolyPhen-2. p.L373F did not alter transcriptional activity in HeLa and HEK293 cells. p.G369E caused a significant 3.4- and 1.8-fold decrease in transcriptional activities relative to wild-type ALX4 in HEK293 and HeLa cells, respectively.

DISCUSSION AND CONCLUSIONS

Our study supports the idea that transcription factors like ALX4 could influence the normal development of the GU tract in humans as demonstrated in mouse models as ALX4 variant p.G369E (predicted pathogenic by multiple databases) affects ALX4 function in vitro. Variant p.L373F (predicted pathogenic by only MutationTaster) did not affect ALX4 function in vitro. Exon-sequence information and mouse genetics provide important insights into the complex mechanisms driving genitourinary defects allowing the association of transcriptional defects with congenital disorders.

Classic bladder exstrophy and adenocarcinoma of the bladder: Methylome analysis provide no evidence for underlying disease-mechanisms of this association

The bladder exstrophy-epispadias complex (BEEC) represents the severe end of uro-rectal malformation spectrum involving aberrant embryonic morphogenesis of the cloacal membrane and the urorectal septum. The most common form of BEEC is isolated classic bladder exstrophy (CBE). Long-term complications in CBE are malignancies of the bladder with 95% of them being adenocarcinomas. Since CBE and adenocarcinoma of the bladder are rare entities, their frequent co-occurrence suggests a common etiology. Recent studies suggest that promoter methylation of various genes play a crucial role during the phenotypical morphogenesis of adenocarcinomas of urinary bladder. To examine, whether epigenetic processes such as DNA methylation patterns are potentially associated with CBE, we performed Illumina 450 K methylation arrays in blood (n = 10) and tissue samples (n = 2) of CBE patients and healthy matched controls (n = 12). In our analysis, we found total lack of methylation in the blood and methylation differences were restricted to 10 CpG sites in the tissue samples. In comparison to other bladder anomalies, CBE tissue methylation profiles differ from those of adenocarcinoma, adenocarcinoma with CBE, urothelial carcinoma and urachal carcinoma. In this preliminary study, we did not provide any strong evidence of major DNA methylation alterations which would be suggestive for strong underlying epigenetic mechanism. However, larger studies are required to provide more robust statistical evidence to exclude smaller effects in the tissues.

Recent Trends in the Management of Bladder Exstrophy: The Gordian Knot Has Not Yet Been Cut

Although enormous effort has been made to further improve the operative techniques worldwide, the management of bladder exstrophy (BE) remains one of the most significant challenges in pediatric urology. Today it is universally agreed that successful and gentle initial bladder closure is decisive for favorable long-term outcome with regard to bladder capacity, renal function and continence. Due to a number of reasons, including a lack of comparable multicenter studies, a range of concepts is currently used to achieve successful primary closure. We review the literature of the last 15 years on the current concepts of bladder exstrophy repair with regard to the time of primary closure (initial vs. delayed closure), the concepts of primary closure (single-stage vs. staged approach; without osteotomy vs. osteotomy) and their outcomes. There is a worldwide lack of multicenter outcome studies with adequate patient numbers and precisely defined outcome parameters, based on the use of validated instruments. The modern staged repair (MRSE) in different variations, the complete primary reconstruction of exstrophy (CPRE), and the radical soft-tissue mobilization (RSTM) had been the most extensively studied and reported procedures. These major concepts are obligatory stable now for more than 20 years. Nevertheless, there are still a lot of open-ended questions e.g., on the potential for development of the bladder template, on continence, on long-term orthopedic outcome, on sexuality and fertility and on quality of life. Management of BE remains difficult and controversial. Further, clinical research should focus on multi-institutional collaborative trials to determine the optimal approach.

The intravesical phallus in patients with cloacal exstrophy: An embryologic conundrum

BACKGROUND

Phalluses present inside the extrophied bladder of cloacal exstrophy (CE) newborns have been sporadically reported in the literature; this clinical entity has largely unknown origins and may represent an extremely rare anomaly of CE.

OBJECTIVE

Along with nearly doubling the number of reported intravesical phalluses in the literature, this study aims to outline the common anatomic features and discuss the implications for theories of CE embryogenesis.

STUDY DESIGN

The authors retrospectively identified patients with CE and a potential intravesical phallus between 1997 and 2017 at two high-volume centers. Information was obtained about karyotype, age at closure, neurologic and renal anomalies, diastasis, phallus anatomy, and phallus biopsy pathology.

RESULTS

Six genotypic males met the inclusion criteria. Five of six had a diastasis greater than 6 cm. Four of six had paired corporal bodies in the intravesical phallus, one had a single corporal body, and one had a corporal-like structure. Five of six patients had a phallus located midline in the caudal aspect of the bladder; one was located midline in the bladder dome. Phallic biopsies were obtained in three of six patients. Two showed glanular and corporal tissue while the other showed vascular proliferation morphologically similar to that of erectile tissue.

DISCUSSION

Previous reports suggested that a superior vesicle fissure configuration, fusion of the corporal bodies, and fused bladder plates were common findings with an intravesical phallus. With the addition of new cases, the only consistent variable between patients is a phallus located anywhere along the bladder plate that can comprise a corporal-like structure, a single corporal body, or fused corporal bodies. These findings have implications for several embryologic theories. Although this is a retrospective review with a limited number of patients, the condition is exceedingly infrequent making it only observable retrospectively over decades at high volume centers.

CONCLUSIONS

The study outlined common anatomic features of the intravesical phallus in cloacal exstrophy and discussed the subsequent embryologic implications. In cloacal exstrophy newborns with presumed aphallia, meticulous inspection of the bladder plate and biopsy of any potential phallic structures can prevent resection of phallic tissue.

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.

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.

Epispadias and the associated embryopathies: genetic and developmental basis

The abnormalities in the urogenital organs are frequently observed as human developmental diseases. Among such diseases, the defects in the upper part of external genitalia are rather rare named epispadias. The cleft in the dorsal part of external genitalia often reaches to the urethra. In general, the urogenital abnormalities accompany defects in the adjacent tissues and organs. The ventral body wall and bladder can also be affected in the patients with dorsal defects of the external genitalia. Therefore, such multiple malformations are often classified as bladder exstrophy and epispadias complex (BEEC). Because of the lower frequency of such birth defects and their early embryonic development, animal models are required to analyze the pathogenic mechanisms and the functions of responsible genes. Mutant mouse analyses on various signal cascades for external genitalia and body wall development are increasingly performed. The genetic interactions between growth factors such as bone morphogenetic proteins (Bmp) and transcription factors such as Msx1/2 and Isl1 have been suggested to play roles for such organogenesis. The significance of epithelial-mesenchymal interaction (EMI) is suggested during development. In this review, we describe on such local interactions and developmental regulators. We also introduce some mutant mouse models displaying external genitalia-body wall abnormalities.