Anne-Karoline Ebert

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.

Epidemiological Survey of 214 Families With Bladder Exstrophy-Epispadias Complex

PURPOSE We sought to identify causative nongenetic and genetic risk factors for the bladder exstrophy-epispadias complex. MATERIALS AND METHODS A total of 237 families with the bladder exstrophy-epispadias complex were invited to participate in the study, and information was obtained from 214 families, mainly from European countries. RESULTS Two families showed familial occurrence. Male predominance was found among all subgroups comprising epispadias, classic bladder exstrophy and cloacal exstrophy, with male-to-female ratios of 1.4:1, 2.8:1 and 2.0:1, respectively (p = 0.001). No association with parental age, maternal reproductive history or periconceptional maternal exposure to alcohol, drugs, chemical noxae, radiation or infections was found. However, periconceptional maternal exposure to smoking was significantly more common in patients with cloacal exstrophy than in the combined group of patients with epispadias/classic bladder exstrophy (p = 0.009). Only 16.8% of mothers followed the current recommendations of periconceptional folic acid supplementation, and 17.6% had started supplementation before 10 weeks of gestation. Interestingly, in the latter group mothers of patients with cloacal exstrophy were more compliant with folic acid supplementation than were mothers of the combined group of patients with epispadias/classic bladder exstrophy (p = 0.037). Furthermore, mothers of children with cloacal exstrophy knew significantly more often prenatally that their child would have a congenital malformation than did mothers of children with epispadias/classic bladder exstrophy (p <0.0001). CONCLUSIONS Our study corroborates the hypothesis that epispadias, classic bladder exstrophy and cloacal exstrophy are causally related, representing a spectrum of the same developmental defect, with a small risk of recurrence within families. Embryonic exposure to maternal smoking appears to enforce the severity, whereas periconceptional folic acid supplementation does not seem to alleviate it. There is a disproportional prenatal ultrasound detection rate between severe and mild phenotypes, possibly due to the neglect of imaging of full bladders with a focus on neural tube defects.

Microduplications at 22q11.21 are associated with non-syndromic classic bladder exstrophy

The exstrophy-epispadias complex (EEC) comprises a spectrum of urogenital anomalies in which part or all of the distal urinary tract fails to close. The present study aimed to identify microaberrations characterized by loss or gain of genomic material that contribute to the EEC at a genome-wide level. Molecular karyotyping, utilizing 549,839 single nucleotide polymorphisms (SNPs) with an average spacing of 5.7 kilobases, was performed to screen an initial cohort of 16 patients with non-syndromic EEC. A de novo microduplication involving chromosomal region 22q11.21 was identified in one patient with classic exstrophy of the bladder (CBE). Subsequent multiplex ligation-dependent probe amplification (MLPA) analysis was performed with an MLPA 22q11 kit in a further 50 non-syndromic EEC cases. We identified one CBE patient with an overlapping 22q11.21 duplication in whom the duplication had been transmitted from the unaffected mother. Chromosomal region 22q11 is well known for its susceptibility to genomic rearrangements, and these are associated with various syndromes including the velo-cardio-facial/DiGeorge syndrome (VCFS/DGS), the der(22) syndrome, and the cat-eye syndrome. Duplications in this region result in a wide and variable spectrum of clinical presentations that include features of the VCFS/DGS, while some carriers present with a completely normal phenotype. Our findings extend the phenotypic spectrum of the 22q11.2 duplication syndrome, and indicate that this aberration predisposes to CBE with incomplete penetrance.

Delayed-onset Ureteral Obstruction After Endoscopic Dextranomer/Hyaluronic Acid Copolymer (Deflux) Injection for Treatment of Vesicoureteral Reflux in Children: A Case Series

We report 4 patients with upper urinary tract (UUT) obstruction requiring ureteric reimplantation at 1, 7, 28, and 63 months after dextranomer/hyaluronic acid copolymer (Dx/HA) injection for vesicoureteric reflux. Histopathologic evaluation of ureteric segments revealed extensive foreign body formation in all cases. We conclude that UUT obstruction is a rare but serious complication after Dx/HA injection that can occur even years after surgery. The incidence of delayed-onset UUT obstruction may be higher than previously noted. Long-term follow-up and a critical reappraisal of the method are needed to assess the late sequelae of Dx/HA injection therapy for vesicoureteric reflux.

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.

Persistent Histological Changes in the Exstrophic Bladder After Primary Closure—A Cause for Concern?

PURPOSE We investigated bladder biopsies from patients with classic bladder exstrophy for the histological features and discuss the potential clinical significance of the findings. MATERIALS AND METHODS Bladder tissues were collected from patients with bladder exstrophy between 2004 and 2011. These specimens were obtained at primary bladder closure (group 1, 29 patients), during secondary reconstructive procedures (group 2, 27) or during cystectomy for failed reconstruction (group 3, 15). All tissue specimens were investigated for inflammatory, proliferative, metaplastic and dysplastic changes. Expression of urothelial differentiation markers CK13 and CK20 was determined by immunohistochemical analysis. RESULTS Inflammatory, proliferative and metaplastic changes were found in bladder specimens of all subgroups. Neither dysplasia nor neoplasia was present. Severe epithelial changes such as cystitis glandularis and intestinal metaplasia were observed in up to 62% of bladders several years after primary closure. Aberrant expression patterns of CK13 and CK20 suggesting abnormal urothelial differentiation were shown to be present in the urothelium of all subgroups. CONCLUSIONS Our findings provide prima facie evidence that the epithelial changes observed in the unclosed bladder template persist or even progress in a subset of bladders after primary closure. Although the malignant potential of cystitis glandularis and intestinal metaplasia is controversial, some patients may be at increased risk for dysplasia/neoplasia in the long term. Since the natural history of these lesions in the exstrophic bladder is unknown, these patients require lifelong surveillance.

Expression and Potential Clinical Significance of Urothelial Cytodifferentiation Markers in the Exstrophic Bladder

PURPOSE We characterize the urothelium from patients with classic bladder exstrophy-epispadias complex for the expression of proteins associated with urothelial differentiation, and discuss a potential impact of urothelial phenotype on the structural and functional properties of the bladder template following bladder closure. MATERIALS AND METHODS From 2005 to 2010 bladder biopsies from 32 infants with bladder exstrophy-epispadias complex obtained at primary bladder closure were collected. After histological assessment immunochemistry was used to investigate the expression of uroplakin IIIa, cytokeratin differentiation restricted antigens CK13 and CK20, and tight junction protein claudin 4. RESULTS Overall tissue morphology showed gross alterations with inflammatory, proliferative and metaplastic changes in most specimens. Sections of intact epithelium were present in 78% of biopsies. With respect to urothelial phenotype, CK13 was expressed in all specimens, whereas UPIIIa and CK20 were absent in 76% of the tissues examined. Of the biopsies 52% revealed an irregular expression pattern of tight junction protein Cl-4. CONCLUSIONS This is the first study to our knowledge to characterize the urothelium from infants with bladder exstrophy-epispadias complex for the expression of urothelial differentiation associated antigens. Our findings suggest urothelial differentiation changes in a majority of exstrophic bladders, at least at primary bladder closure. Although the underlying etiology remains to be established, abnormal urothelial differentiation may result in a dysfunctional urothelial barrier with implications for the structural and functional properties of the bladder template. Despite the study limitations, our preliminary findings provide a platform for further investigation of the significance of the urothelium for the exstrophic bladder.

Paediatric urology: Is osteotomy necessary for primary exstrophy closure?

A recent study has reported a novel approach to primary bladder exstrophy closure without osteotomy in newborns. In this study, most patients were managed on a paediatric urology ward with an epidural catheter, with similar outcomes to patients treated in an intensive care unit with ventilation and muscle relaxation.

Family-based association study of the MTHFR polymorphism C677T in the bladder-exstrophy-epispadias-complex†

Heiko Reutter,* Tim Becker, Michael Ludwig, Niklas Schäfer, Birte Detlefsen, Sylvie Beaudoin, Margit Fisch, Anne-Karoline Ebert, Wolfgang Rösch, Markus M. Nöthen, Thomas M. Boemers, and Regina C. Betz Department of Human Genetics, University of Bonn, Bonn, Germany Institute for Medical Biometry, Informatics and Epidemiology, University of Bonn, Bonn, Germany Department of Clinical Biochemistry, University of Bonn, Bonn, Germany Department de Chirurgie Pédiatrique, Hôpital Saint-Vincent de Paul, Paris, France Department of Urology, General Hospital Harburg, Hamburg, Germany Department of Pediatric Urology, St. Hedwig Hospital Barmherzige Brüder, Regensburg, Germany Department of Genomics, Life & Brain Center, University of Bonn, Bonn, Germany Department of Pediatric Surgery and Pediatric Urology, Childrens Hospital, Köln, Germany

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.