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.

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.

Narrowing the chromosome 22q11.2 locus duplicated in bladder exstrophy-epispadias complex.

INTRODUCTION: Bladder exstrophy-epispadias complex (BEEC) comprises a spectrum of anterior midline congenital malformations, involving the lower urinary tract. BEEC is usually sporadic, but families with more than one affected member have been reported, and a twin concordance study supported a genetic contribution to pathogenesis. Moreover, diverse chromosomal aberrations have been reported in a small subset of individuals with BEEC. The commonest are 22q11.2 microduplications, identified in approximately 3% of BEEC index cases. OBJECTIVES: We aimed to refine the chromosome 22q11.2 locus, and to determine whether the encompassed genes are expressed in normal developing and mature human urinary bladders. RESULTS: Using DNA from an individual with CBE, the 22q11.2 duplicated locus was refined by identification of a maternally inherited 314 kb duplication (chr22:21,147,293-21,461,017), as depicted in this image. Moreover, the eight protein coding genes within the locus were found to be expressed during normal developing and mature bladders. To determine whether duplications in any of these individual genes were associated with CBE, we undertook copy number analyses in 115 individuals with CBE without duplications of the whole locus. No duplications of individual genes were found. DISCUSSION: The current study has refined the 22q11.2 locus associated with BEEC and has shown that the eight protein coding genes are expressed in human bladders both during antenatal development and postnatally. Nevertheless, the precise biological explanation as to why duplication of the phenocritical region of 22q11 confers increased susceptibility to BEEC remains to be determined. The fact that individuals with CBE without duplications of the whole locus also lacked duplication of any of the individual genes suggests that in individuals with BEEC and duplication of the 22q11.2 locus altered dosage of more than one gene may be important in BEEC etiology. CONCLUSIONS: The study has refined the 22q11.2 locus associated with BEEC and has shown that the eight protein coding genes within this locus are expressed in human bladders.

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.

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.

Further support linking the 22q11.2 microduplication to an increased risk of bladder exstrophy and highlighting LZTR1 as a candidate gene.

BACKGROUND: The bladder exstrophy-epispadias complex (BEEC) is a congenital malformation of the bladder and urethra. The underlying causes of this malformation are still largely unknown; however, aside from environment, genetics is thought to play an essential role. The recurrent 22q11.2 microduplication is the most persistently detected genetic aberration found in BEEC cases. METHODS: We performed array comparative genomic hybridization (array-CGH) analysis of 76 Swedish BEEC patients. Statistical analysis was performed on current dataset pooled with previously published data on the 22q11.2 microduplication in BEEC patients. We performed massive parallel sequencing (MPS) of the 22q11.2 region in 20 BEEC patients without the 22q11.2 microduplication followed by functional studies. RESULTS: We identified three additional cases with the 22q11.2 microduplication. Pooling data from this study with previously published reports showed a statistically significant enrichment of the 22q11.2 microduplication in BEEC patients (2.61% in cases vs. 0.08% in controls; OR = 32.6; p = 8.7 × 10-4 ). MPS of the 22q11.2 region in 20 BEEC patients without the 22q11.2 microduplication identified a novel variant in LZTR1 (p.Ser698Phe) in one patient. Functional evaluation of the LZTR1 p.Ser698Phe variant in live NIH 3T3 cells showed that the concentration and cytoplasmic mobility differ between the Lztr1wt and Lztr1mut , indicating a potential functional effect of the LZTR1mut . CONCLUSION: Our study further emphasizes the involvement of the 22q11.2 region in BEEC development and highlights LZTR1 as a candidate gene underlying the urogenital malformation.

[The German research network CURE-Net : A benefit for patients with rare diseases]. / Das deutsche Forschungsnetzwerk CURE-Net : Ein Gewinn für Patienten mit seltenen Erkrankungen.

With the help of the media, there is growing public awareness for the problems associated with rare diseases and their impact on the lives of those affected and their families. Bladder exstrophy-epispadias complex (BEEC) is also a part of the group of rare diseases within the urological field. The German network CURE-Net was founded in 2009 to systematically collect data regarding the epidemiological and molecular causes, and clinical and psychosocial effects of congenital urorectal malformations. With the help of self-help groups a national registry could be established for systematic data retrieval. This research can help to improve existing medical care and follow-up for affected individuals with BEEC.

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.

PLAGL1 epimutation and bladder exstrophy: Coincidence or concurrent etiology?

BACKGROUND: The bladder exstrophy-epispadias complex (BEEC) is characterized by a spectrum of genitourinary malformations. Both classical bladder exstrophy and the most severe phenotype, exstrophy of the cloaca, display omphaloceles, a cardinal anomaly of some disorders caused by altered imprinting. Therefore, we hypothesized that BEEC in some patients could occur on the basis of an undiagnosed imprinting disorder. Such altered imprinting is associated with changes in the parent-of-origin-specific DNA methylation. METHODS: We analyzed the DNA methylation of 54 imprinted loci in 23 selected patients with different BEEC subtypes (epispadias n = 1, classical bladder exstrophy n = 10, exstrophy of the cloaca n = 12) using the Infinium HumanMethylation450 BeadChip. A total of 471,722 not imprinted autosomal CpG loci and 891 imprinted CpG loci were investigated. Findings were corroborated by methylation-specific-multiplex ligation-dependent probe amplification (MS-MLPA) and microsatellite analysis. RESULTS: No significant differences in the DNA methylation of the not imprinted and imprinted CpG were observed depending on subtype of BEEC. Nevertheless, in 1 of the 23 patients who displayed a classical bladder exstrophy, we detected hypomethylation of the imprinted PLAGL1 locus in chromosome 6q24. We verified this hypomethylation by MS-MLPA and showed further the methylation loss to be caused most likely by a mosaic epimutation. CONCLUSION: Considering that it is highly unlikely to detect a PLAGL1 epimutation among 23 individuals given the low incidence of this alteration in the population, our observations further support a link between BEEC and imprinting disorders. Birth Defects Research (Part A) 106:724-728, 2016. © 2016 Wiley Periodicals, Inc.

Is 1p36 deletion associated with anterior body wall defects?

Epispadias and exstrophy of the cloaca, also known as OEIS complex (omphalocele, exstrophy, imperforate anus, spinal defects), respectively constitute the most benign and severe ends of the bladder exstrophy-epispadias complex (BEEC) spectrum. In 2009, El-Hattab et al. reported the first patient with OEIS complex associated with a chromosome 1p36 deletion. Here we report a second patient with 1p36 deletion who also has classic bladder exstrophy, supporting the possible role of genes in this region in the development of BEEC. The absence of omphalocele and imperforate anus in our patient places him toward classic bladder exstrophy while presence of spina bifida and the absence of coccyx suggest an overlap with OEIS complex. An additional differential diagnosis is the pentalogy of Cantrell in our patient as he also has a diaphragmatic hernia and an incomplete sternum. This is the second observation of a ventral midline birth defect in association with 1p36 deletion syndrome, following El-Hattab et al.'s report [2009]. The three genes (NOCL2, DVL1, and MMP23B) discussed as possible candidates are also among the deleted ones in our patient, supporting the possible role of these genes in BEEC spectrum. © 2016 Wiley Periodicals, Inc.

Bladder exstrophy-epispadias complex and triple-X syndrome: incidental finding or causality?

BACKGROUND: Bladder exstrophy is a rare malformation. Prenatal diagnosis is usually an incidental finding on routine ultrasound examination. Triple-X syndrome (karyotype 47,XXX) is the most frequent sex chromosome aneuploidy in live-born females (approximately 1 in 1000). The diagnosis is often not made because women with 47,XXX karyotype have no or hardly any clinical symptoms during life. METHODS: Prenatal diagnosis of triple X karyotype is usually an incidental finding when an invasive prenatal diagnosis is performed for other reasons. RESULTS: Here, we report on two cases with bladder exstrophy and triple-X syndrome, one in a fetus and one in an adult. In view of two previous reports of this association in literature, causality of these two conditions should be considered. CONCLUSION: A gene dosage effect as possible underlying mechanisms will be discussed.

Classic bladder exstrophy: Frequent 22q11.21 duplications and definition of a 414 kb phenocritical region.

BACKGROUND: Classic bladder exstrophy (CBE) is the most common form of the bladder exstrophy and epispadias complex. Previously, we and others have identified four patients with a duplication of 22q11.21 among a total of 96 unrelated CBE patients. METHODS: Here, we investigated whether this chromosomal aberration was commonly associated with CBE/bladder exstrophy and epispadias complex in an extended case-control sample. Multiplex ligation-dependent probe amplification and microarray-based analysis were used to identify 22q11.21 duplications in 244 unrelated bladder exstrophy and epispadias complex patients (including 217 CBE patients) and 665 healthy controls. RESULTS: New duplications of variable size were identified in four CBE patients and one control. Pooling of our previous and present data (eight duplications in 313 CBE patients) yielded a combined odds ratio of 31.86 (95% confidence interval, 4.24-1407.97). Array-based sequence capture and high-throughput targeted re-sequencing established that all breakpoints resided within the low-copy repeats 22A to 22D. Comparison of the eight duplications revealed a 414 kb phenocritical region harboring 12 validated RefSeq genes. Characterization of these 12 candidate genes through whole-mount in situ hybridization of mouse embryos at embryonic day 9.5 suggested that CRKL, THAP7, and LZTR1 are CBE candidate genes. CONCLUSION: Our data suggest that duplication of 22q11.21 increases CBE risk and implicate a phenocritical region in disease formation.

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.

Identification of Streptococcus parasanguinis DNA contamination in human buccal DNA samples.

BACKGROUND: The use of buccal swabs in clinical and scientific studies is a very popular method of collecting DNA, due to its non-invasive nature of collection. However, contamination of the DNA sample may interfere with analysis. FINDINGS: Here we report the finding of Streptococcus parasanguinis bacterial DNA contamination in human buccal DNA samples, which led to preferential amplification of bacterial sequence with PCR primers designed against human sequence. CONCLUSION: Contamination of buccal-derived DNA with bacterial DNA can be significant, and may influence downstream genetic analysis. One needs to be aware of possible bacterial contamination when interpreting abnormal findings following PCR amplification of buccal swab DNA samples.

Candidate gene association study implicates p63 in the etiology of nonsyndromic bladder-exstrophy-epispadias complex.

BACKGROUND: Bladder-exstrophy-epispadias complex (BEEC) is a severe congenital anomaly that represents a spectrum of urological abnormalities where parts or all of the distal urinary tract fail to close during development. Multiple lines of evidence strongly suggested p63 as a plausible candidate gene. We conducted a candidate gene association study to further investigate the role of p63 in human BEEC. METHODS: We conducted a family-based association study of p63 using 154 Caucasian patients with nonsyndromic BEEC and their unaffected parents. High throughput single nucleotide polymorphism (SNP) genotyping was carried out using Illumina's Golden Gate Assay for 109 selected tagging SNPs localized within p63 with a minor allele frequency > 0.01. Individual and haplotype SNP transmission disequilibrium tests were conducted using Plink and Haploview, respectively. We also examined parent-of-origin effects using paternal asymmetry tests implemented in FAMHAP (http://famhap.meb.uni-bonn.de/index.html). RESULTS: Nominally significant associations were identified between BEEC and six SNPs (rs17447782, rs1913720, rs6790167, rs9865857, rs1543969, rs4687100), and four haplotype blocks including or near these significant SNPs. Analysis of parent-of-origin effects showed significant results for seven SNPs (rs4118375, rs12696596, rs6779677, rs13091309, rs7642420, rs1913721, and rs1399774). None of these results remained significant after multiple testing correction. CONCLUSION: The altered transmission of p63 variants in nonsyndromic BEEC patients may be suggestive of its involvement in the disease etiology. Further and large multi-institutional collaborative studies are required to elucidate the role of p63 in nonsyndromic BEEC.

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.

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.

Y chromosome aberration in a patient with cloacal-bladder exstrophy-epispadias complex: an unusual finding / Aberração cromossômica do Y em uma paciente com extrofia de bexiga e de cloaca e epispadia: um achado raro

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 se­xual 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.

Aberrações cromossômicas ou síndromes genéticas associadas ao complexo extrofia de bexiga e de cloaca e epispadia são raramente relatadas. O objetivo é descrever uma paciente brasileira com 14 anos que apresenta uma malformação urogenital complexa, baixa estatura, ausência de características sexuais secundárias e alteração do cromossomo Y. Uma menina com extrofia de bexiga e de cloaca e epispadia foi encaminhada para avaliação de baixa estatura e ausência de desenvolvimento de características sexuais secundárias. Níveis pré-puberais de gonadotrofinas e esteroides sexuais foram observados no início da avaliação, mas durante o seguimento notou-se um aumento progressivo dos níveis de testosterona. Ela foi submetida à gonadectomia e identificou-se a presença de testículos sem características disgenéticas. O cariótipo era 46,X,inv(Y)(p11.1q11.2), com sequência normal do SRY e ausência de deleções do Y. A inversão pericêntrica do cromossomo Y, aparentemente, não contribuiu para o desenvolvimento da malformação urogenital complexa nessa paciente. Atualmente, nenhum agente teratogênico, fator ambiental ou mutações gênicas foram reconhecidos como fatores etiológicos para essa malformação urogenital.

Murine expression and mutation analyses of the prostate androgen-regulated mucin-like protein 1 (Parm1) gene, a candidate for human epispadias.

BACKGROUND: Epispadias is the mildest phenotype of the human bladder exstrophy-epispadias complex (BEEC), and presents with varying degrees of severity. This urogenital birth defect results from a disturbance in the septation process, during which separate urogenital and anorectal components are formed through division of the cloaca. This process is reported to be influenced by androgen signaling. The human PARM1 gene encodes the prostate androgen-regulated mucin-like protein 1, which is expressed in heart, kidney, and placenta. METHODS: We performed whole mount in situ hybridization analysis of Parm1 expression in mouse embryos between gestational days (GD) 9.5 and 12.5, which are equivalent to human gestational weeks 4-6. Since the spatio-temporal localization of Parm1 corresponded to tissues which are affected in human epispadias, we sequenced PARM1 in 24 affected patients. RESULTS: We found Parm1 specifically expressed in the region of the developing cloaca, the umbilical cord, bladder anlage, and the urethral component of the genital tubercle. Additionally, Parm1 expression was detected in the muscle progenitor cells of the somites and head mesenchyme. PARM1 gene analysis revealed no alterations in the coding region of any of the investigated patients. CONCLUSIONS: These findings suggest that PARM1 does not play a major role in the development of human epispadias. However, we cannot rule out the possibility that a larger sample size would enable detection of rare mutations in this gene.