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.

Genome-wide identification of disease-causing copy number variations in 450 individuals with anorectal malformations

Anorectal malformations (ARM) represent a spectrum of rare malformations originating from a perturbated development of the embryonic hindgut. Approximately 60% occur as a part of a defined genetic syndrome or within the spectrum of additional congenital anomalies. Rare copy number variations (CNVs) have been associated with both syndromic and non-syndromic forms. The present study represents the largest study to date to explore the contribution of CNVs to the expression of ARMs. SNP-array-based molecular karyotyping was applied in 450 individuals with ARM and 4392 healthy controls. CNVs were identified from raw intensity data using PennCNV. Overlapping CNVs between cases and controls were discarded. Remaining CNVs were filtered using a stringent filter algorithm of nine filter steps. Prioritized CNVs were confirmed using qPCR. Filtering prioritized and qPCR confirmed four microscopic chromosomal anomalies and nine submicroscopic CNVs comprising seven microdeletions (del2p13.2, del4p16.2, del7q31.33, del9p24.1, del16q12.1, del18q32, del22q11.21) and two microduplications (dup2p13.2, dup17q12) in 14 individuals (12 singletons and one affected sib-pair). Within these CNVs, based on their embryonic expression data and function, we suggest FOXK2, LPP, and SALL3 as putative candidate genes. Overall, our CNV analysis identified putative microscopic and submicroscopic chromosomal rearrangements in 3% of cases. Functional characterization and re-sequencing of suggested candidate genes is warranted.

Urological Impact of Epididymo-orchitis in Patients with Anorectal Malformation: An ARM-Net Consortium Study

INTRODUCTION

 To investigate the current experience of the ARM-Net Consortium in the management of epididymo-orchitis (EO) in patients with anorectal malformations (ARMs), and to identify specific risk factors and the need for urological care involvement.

MATERIALS AND METHODS

 We retrospectively collected data of EO in patients with ARM between 2015 and 2019. Data on urological aspects, ARM type, surgical approach, associated anomalies, diagnosis, and treatment of EO were collected and analyzed.

RESULTS

 Twenty-nine patients were reported by 12 centers. Twenty-six patients with EO (90%) had ARM with a rectourinary fistula. Median age at first EO was 2 years (range: 15 days-27 years). Twenty patients (69%) experienced multiple EO, and 60% of recurrences were ipsilateral. Associated urological anomalies included vesicoureteral reflux (48%), urethral anomalies (41%), neurogenic bladder (41%), and ectopic vas (10%). A positive urine culture during EO was present in 69%. EO was treated with antibiotics (90%), limiting surgical exploration to 14%. Prevention of recurrences included surgery (bulking agents 15%, vasectomy 15%, and orchiectomy 5%) and antibiotic prophylaxis (20%).

CONCLUSION

 Urologists may encounter patients with EO in ARM patients, frequently with positive urine culture. An appropriate urologic work-up for most ARM patients is necessary to identify and treat underlying risk factors. A practical scheme for the work-up is suggested for a close collaboration between pediatric surgeons and urologists.

Bowel function and associated risk factors at preschool and early childhood age in children with anorectal malformation type rectovestibular fistula: An ARM-Net consortium study

BACKGROUND

Outcome of patients operated for anorectal malformation (ARM) type rectovestibular fistula (RVF) is generally considered to be good. However, large multi-center studies are scarce, mostly describing pooled outcome of different ARM-types, in adult patients. Therefore, counseling parents concerning the bowel function at early age is challenging. Aim of this study was to evaluate bowel function of RVF-patients at preschool/early childhood age and determine risk factors for poor functional outcome.

METHODS

A multi-center cohort study was performed. Patient characteristics, associated anomalies, sacral ratio, surgical procedures, post-reconstructive complications, one-year constipation, and Bowel Function Score (BFS) at 4-7 years of follow-up were registered. Groups with below normal (BFS < 17; subgroups 'poor' ≤ 11, and 'fair' 11 < BFS < 17) and good outcome (BFS ≥ 17) were formed. Univariable analyses were performed to detect risk factors for outcome.

RESULTS

The study included 111 RVF-patients. Median BFS was 16 (range 6-20). The 'below normal' group consisted of 61 patients (55.0%). Overall, we reported soiling, fecal accidents, and constipation in 64.9%, 35.1% and 70.3%, respectively. Bowel management was performed in 23.4% of patients. Risk factors for poor outcome were tethered cord and low sacral ratio, while sacral anomalies, low sacral ratio, prior enterostomy, post-reconstructive complications, and one-year constipation were for being on bowel management.

CONCLUSIONS

Although median BFS at 4-7 year follow-up is nearly normal, the majority of patients suffers from some degree of soiling and constipation, and almost 25% needs bowel management. Several factors were associated with poor bowel function outcome and bowel management.

LEVEL OF EVIDENCE

Level III.

Clinical Differentiation between a Normal Anus, Anterior Anus, Congenital Anal Stenosis, and Perineal Fistula: Definitions and Consequences—The ARM-Net Consortium Consensus

In the past, an anteriorly located anus was often misdiagnosed and treated as an anorectal malformation (ARM) with a perineal fistula (PF). The paper aims to define the criteria for a normal anus, an anterior anus (AA) as an anatomic variant, and milder types of ARM such as congenital anal stenosis (CAS) and PF. An extensive literature search was performed by a working group of the ARM-Net Consortium concerning the subject “Normal Anus, AA, and mild ARM”. A consensus on definitions, clinical characteristics, diagnostic management, and treatment modalities was established, and a diagnostic algorithm was proposed. The algorithm enables pediatricians, midwives, gynecologists, and surgeons to make a timely correct diagnosis of any abnormally looking anus and initiate further management if needed. Thus, the routine physical inspection of a newborn should include the inspection of the anus and define its position, relation to the external sphincter, and caliber. A correct diagnosis and use of the presented terminology will avoid misclassifications and allow the initiation of correct management. This will provide a reliable comparison of different therapeutic management and outcomes of these patient cohorts in the future.

Re-sequencing of candidate genes FOXF1, HSPA6, HAAO, and KYNU in 522 individuals with VATER/VACTERL, VACTER/VACTERL-like association, and isolated anorectal malformation

BACKGROUND

The acronym VATER/VACTERL association describes the combination of at least three component features (CFs): vertebral defects (V), anorectal malformations (ARM) (A), cardiac defects (C), tracheoesophageal fistula with or without esophageal atresia (TE), renal malformations (R), and limb defects (L). Individuals presenting two CFs have been termed VATER/VACTERL-like. Recently, FOXF1, HSPA6, HAAO, KYNU, TRAP1, and ZIC3 have been proposed as candidate genes for VATER/VACTERL, VATER/VACTERL-like, and ARM. Re-sequencing studies identified disease-causing variants in TRAP1 and ZIC3, the contribution of other genes was not independently investigated. One affected variant carrier in FOXF1 was previously identified. Here we re-sequenced FOXF1, HSPA6, HAAO, and KYNU in 522 affected individuals.

METHODS

Using molecular inversion probe (MIP) technology, re-sequencing was performed in 63 individuals with VATER/VACTERL association, 313 with VATER/VACTERL-like association, and 146 with ARM. All individuals were of European ethnicity. Variant filtering considered variants with a minor allele frequency (MAF) ≤0.01 for putative recessive disease-genes HSPA6, HAAO, and KYNU. For the putative dominant disease-gene FOXF1 we considered variants with a MAF ≤0.0001. In silico prediction tools were used for further prioritization.

RESULTS

Only two variants in FOXF1 in two independently affected individuals [c.443G>T, p.(Cys148Phe); c.850T>C, p.(Tyr284His)] passed our filter criteria. One individual presented with ARM, the second presented with TE and C comprising atrial and ventricular septal defects. Sanger sequencing confirmed both variants but also their inheritance from the healthy mother.

CONCLUSION

Our analysis suggests that FOXF1, HSPA6, HAAO and KYNU do not play a major role in the formation of VACTER/VACTERL phenotypes or ARM.

Exome survey of individuals affected by VATER/VACTERL with renal phenotypes identifies phenocopies and novel candidate genes

The acronym VATER/VACTERL refers to the rare nonrandom association of the following component features (CFs): vertebral defects (V), anorectal malformations (ARM) (A), cardiac anomalies (C), tracheoesophageal fistula with or without esophageal atresia (TE), renal malformations (R), and limb anomalies (L). For the clinical diagnosis, the presence of at least three CFs is required, individuals presenting with only two CFs have been categorized as VATER/VACTERL-like. The majority of VATER/VACTERL individuals displays a renal phenotype. Hitherto, variants in FGF8, FOXF1, HOXD13, LPP, TRAP1, PTEN, and ZIC3 have been associated with the VATER/VACTERL association; however, large-scale re-sequencing could only confirm TRAP1 and ZIC3 as VATER/VACTERL disease genes, both associated with a renal phenotype. In this study, we performed exome sequencing in 21 individuals and their families with a renal VATER/VACTERL or VATER/VACTERL-like phenotype to identify potentially novel genetic causes. Exome analysis identified biallelic and X-chromosomal hemizygous potentially pathogenic variants in six individuals (29%) in B9D1, FREM1, ZNF157, SP8, ACOT9, and TTLL11, respectively. The online tool GeneMatcher revealed another individual with a variant in ZNF157. Our study suggests six biallelic and X-chromosomal hemizygous VATER/VACTERL disease genes implicating all six genes in the expression of human renal malformations.

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.

Treatment Strategies and Outcome of the Exstrophy-Epispadias Complex in Germany: Data From the German CURE-Net

Introduction: To evaluate the impact of reconstructive strategies and post-operative management on short- and long-term surgical outcome and complications of classical bladder exstrophy (CBE) patients' comprehensive data of the multicenter German-wide Network for Congenital Uro-Rectal malformations (CURE-Net) were analyzed. Methods: Descriptive analyses were performed between 34 prospectively collected CBE patients born since 2009, median 3 months old [interquartile range (IQR), 2-4 months], and 113 cross-sectional patients, median 12 years old (IQR, 6-21 years). Results: The majority of included individuals were males (67%). Sixty-eight percent of the prospectively observed and 53% of the cross-sectional patients were reconstructed using a staged approach (p = 0.17). Although prospectively observed patients were operated on at a younger age, the post-operative management did not significantly change in the years before and after 2009. Solely, in prospectively observed patients, peridural catheters were used significantly more often (p = 0.017). Blood transfusions were significantly more frequent in males (p = 0.002). Only half of all CBE individuals underwent inguinal hernia repair. Cross-sectional patients after single-stage reconstructions showed more direct post-operative complications such as upper urinary tract dilatations (p = 0.0021) or urinary tract infections (p = 0.023), but not more frequent renal function impairment compared to patients after the staged approach (p = 0.42). Continence outcomes were not significantly different between the concepts (p = 0.51). Self-reported continence data showed that the majority of the included CBE patients was intermittent or continuous incontinent. Furthermore, subsequent consecutive augmentations and catheterizable stomata did not significantly differ between the two operative approaches. Urinary diversions were only reported after the staged concept. Conclusions: In this German multicenter study, a trend toward the staged concept was observed. While single-stage approaches tended to have initially more complications such as renal dilatation or urinary tract infections, additional surgery such as augmentations and stomata appeared to be similar after staged and single-stage reconstructions in the long term.

A Genetics-First Approach Revealed Monogenic Disorders in Patients With ARM and VACTERL Anomalies

Background: The VATER/VACTERL association (VACTERL) is defined as the non-random occurrence of the following congenital anomalies: Vertebral, Anal, Cardiac, Tracheal-Esophageal, Renal, and Limb anomalies. As no unequivocal candidate gene has been identified yet, patients are diagnosed phenotypically. The aims of this study were to identify patients with monogenic disorders using a genetics-first approach, and to study whether variants in candidate genes are involved in the etiology of VACTERL or the individual features of VACTERL: Anorectal malformation (ARM) or esophageal atresia with or without trachea-esophageal fistula (EA/TEF). Methods: Using molecular inversion probes, a candidate gene panel of 56 genes was sequenced in three patient groups: VACTERL (n = 211), ARM (n = 204), and EA/TEF (n = 95). Loss-of-function (LoF) and additional likely pathogenic missense variants, were prioritized and validated using Sanger sequencing. Validated variants were tested for segregation and patients were clinically re-evaluated. Results: In 7 out of the 510 patients (1.4%), pathogenic or likely pathogenic variants were identified in SALL1, SALL4, and MID1, genes that are associated with Townes-Brocks, Duane-radial-ray, and Opitz-G/BBB syndrome. These syndromes always include ARM or EA/TEF, in combination with at least two other VACTERL features. We did not identify LoF variants in the remaining candidate genes. Conclusions: None of the other candidate genes were identified as novel unequivocal disease genes for VACTERL. However, a genetics-first approach allowed refinement of the clinical diagnosis in seven patients, in whom an alternative molecular-based diagnosis was found with important implications for the counseling of the families.

Non-financial conflicts of interest: contribution to a surgical dilemma by the European Reference Networks for Rare Diseases

PURPOSE

Conflicts of interest can impede both research and medical treatment. The European Reference Networks require their members to deal with financial and non-financial conflicts according to an explicit protocol. In a literature review, we identified relevant interests in paediatric surgery, and drafted such a policy.

METHODS

We conducted a Pubmed query and identified additional publications based on the content of the papers.

RESULTS

58 titles were identified. According to their abstracts, 10 publications were studied in full text. A scientific taxonomy does not yet exist, but a variety of factors are mentioned. Non-financial conflicts of interest are addressed less accurately and less frequently than financial ones, especially regarding surgical treatment. Since the clinical effect of surgical volume was identified as being relevant, additional 29 respective publications were analysed. This volume-quality relationship causes conflicts of interest for the many surgeons treating a broad spectrum of rare conditions. We present a recommendation that may guide referral of patients requiring complex surgery to centres with a higher volume.

CONCLUSIONS

Non-financial conflicts of interest need to be dealt with more accuracy, especially with regard to surgery in rare, complex congenital conditions. The European Reference Networks offer a framework to mitigate these conflicts.

HSPA6: A new autosomal recessive candidate gene for the VATER/VACTERL malformation spectrum

BACKGROUND

The VATER/VACTERL association refers to the nonrandom co-occurrence of at least three of the following component features (CFs): vertebral defects (V), anorectal malformations (ARM) (A), cardiac defects (C), tracheoesophageal fistula with or without esophageal atresia (TE), renal malformations (R), and limb defects (L). Patients presenting with two CFs have been termed VATER/VACTERL-like phenotypes.

METHODS

We surveyed the exome for recessive disease variants in three affected sib-pairs. Sib-pair 971 consisted of two brothers with ARM and additional hydronephrosis in one brother. Sib-pair 1098 consisted of two sisters with ARM. In family 1346, the daughter presented with ARM and additional hypoplasia of both small fingers and ankyloses. Her brother presented with unilateral isolated radial hypoplasia. Sib-pairs 971 and 1346 resembled a VATER/VACTERL-like phenotype.

RESULTS

We detected a novel maternally inherited missense variant (c.1340G > T) and a rare paternally inherited deletion of the trans-allele in HSPA6 in both siblings of family 1346. HSPA6 belongs to the heat shock protein (HSP) 70 family. Re-sequencing of HSPA6 in 167 patients with VATER/VACTERL and VATER/VACTERL-like phenotypes did not reveal any additional bi-allelic variants.

CONCLUSIONS

Until now, only TNF-receptor associated protein 1 (TRAP1) had been reported as an autosomal recessive disease-gene for the VATER/VACTERL association. TRAP1 belongs to the heat shock protein 90 family (HSP90). Both Hsp70 and Hsp90 genes have been shown to be important embryonic drivers in the formation of mouse embryonic forelimb tissue. Our results suggest HSPA6 as a new candidate gene in VATER/VACTERL-like phenotypes.

Epidemiologic analysis of families with isolated anorectal malformations suggests high prevalence of autosomal dominant inheritance

BACKGROUND

Anorectal malformations (ARM) are rare abnormalities that occur in approximately 1 in 3000 live births with around 40% of patients presenting with isolated forms. Multiple familial cases reported, suggest underlying genetic factors that remain largely unknown. The recurrence in relatives is considered rare, however transmission rates of ARM by affected parents have never been determined before. The inheritance pattern of ARM was investigated in our database of patients with isolated ARM.

RESULTS

Within our cohort of 327 patients with isolated ARM we identified eight adult patients from eight families who had in total 16 children with their healthy spouse. Of these ten had ARM, resulting in a recurrence risk of approximately one in two live births (10 of 16; 62%). From 226 families with 459 siblings we found two affected siblings in five families. Hence, the recurrence risk of ARM among siblings is approximately one in 92 live births (5 of 459; 1.0%).

CONCLUSIONS

Comparing the observed recurrence risk in our cohort with the prevalence in the general population, we see a 1500-fold increase in recurrence risk for offspring and a 32-fold increase if a sibling is affected. The recurrence risk of approximately 62% indicates an autosomal dominant mode of inheritance. Reliable figures on recurrence of ARM are becoming increasingly important since improved surgical techniques are able to maintain sexual function resulting in more offspring of patients with ARM. These data allow more precise counseling of families with ARM and support the need for genetic studies.

Comparison of environmental risk factors for esophageal atresia, anorectal malformations, and the combined phenotype in 263 German families

Esophageal atresia with or without tracheoesophageal fistula (EA/TEF) and anorectal malformations (ARM) represent the severe ends of the fore- and hindgut malformation spectra. Previous research suggests that environmental factors are implicated in their etiology. These risk factors might indicate the influence of specific etiological mechanisms on distinct developmental processes (e.g. fore- vs. hindgut malformation). The present study compared environmental factors in patients with isolated EA/TEF, isolated ARM, and the combined phenotype during the periconceptional period and the first trimester of pregnancy in order to investigate the hypothesis that fore- and hindgut malformations involve differing environmental factors. Patients with isolated EA/TEF (n = 98), isolated ARM (n = 123), and the combined phenotype (n = 42) were included. Families were recruited within the context of two German multicenter studies of the genetic and environmental causes of EA/TEF (great consortium) and ARM (CURE-Net). Exposures of interest were ascertained using an epidemiological questionnaire. Chi-square, Fisher's exact, and Mann-Whitney U-tests were used to assess differences between the three phenotypes. Newborns with isolated EA/TEF and the combined phenotype had significantly lower birth weights than newborns with isolated ARM (P = 0.001 and P < 0.0001, respectively). Mothers of isolated EA/TEF consumed more alcohol periconceptional (80%) than mothers of isolated ARM or the combined phenotype (each 67%). Parental smoking (P = 0.003) and artificial reproductive techniques (P = 0.03) were associated with isolated ARM. Unexpectedly, maternal periconceptional multivitamin supplementation was most frequent among patients with the most severe form of disorder, i.e. the combined phenotype (19%). Significant differences in birth weight were apparent between the three phenotype groups. This might be attributable to the limited ability of EA/TEF fetuses to swallow amniotic fluid, thus depriving them of its nutritive properties. Furthermore, the present data suggest that fore- and hindgut malformations involve differing environmental factors. Maternal periconceptional multivitamin supplementation was highest among patients with the combined phenotype. This latter finding is contrary to expectation, and warrants further analysis in large prospective epidemiological studies.

More than fetal urine: enteral uptake of amniotic fluid as a major predictor for fetal growth during late gestation

The purpose of our study was to investigate the importance of amniotic fluid (AF) for fetal growth during late gestation using esophageal atresia (EA) patients as a model. In this retrospective cohort study, we compared the z-scores adapted for birth weights (BW z-scores) for each of 517 European newborns with congenital pre-gastric intestinal atresia, i.e., EA, to a European reference population. To account for the influence of the intestinal atresia on fetal growth per se, we compared adapted birth weights for each of 504 European newborns with post colonic intestinal atresia (anorectal malformation (ARM) with atresia of the anus) to the same European reference population. Analysis of the complete cohort showed (i) a significantly higher rate of small for gestational age newborns among EA compared to ARM newborns (p < 0.001) and (ii) significantly lower BW z-scores among EA compared to ARM newborns (p < 0.001). BW z-scores of EA newborns were significantly lower in term compared to preterm newborns with an inverse correlation with gestational age (GA) (Spearman correlation coefficient, r = -0.185, p < 0.001).

CONCLUSIONS

Enteral uptake of AF seems to play a pivotal role in fetal growth during late gestation.

WHAT IS KNOWN

• Peak velocity of fetal weight gain occurs at 33 weeks of gestation and continues until birth. During this period, fetal growth is mainly characterized by cellular hypertrophy. • Amniotic fluid (AF) comprises large amounts of hormones and growth regulators. What is New: • A significantly higher rate of small for gestational age and lower birth weights and z-scores are observed among newborn infants with congenital pre-gastric intestinal atresia. • These findings suggest that enteral uptake of AF is a major predictor for fetal growth during late gestation.

The Challenges of the European Anorectal Malformations-Net Registry

Anorectal malformations (ARM) have a low prevalence, patients need specialized surgical care, and in many cases, patients born with ARM even need life-long aftercare. Due to its low prevalence most patients are still treated in low-volume pediatric surgical centers without any adequate monitoring of the outcome. Data on prevalence, comparison of different surgical techniques, and prospective outcome measurements are still scarce and difficult to interpret. In 2010, a consortium was founded (ARM-Net consortium) including several European pediatric surgical centers to collaborate more in research and share knowledge on ARM. One of the structures started by the consortium was an ARM-Net registry for the inclusion of all future patients treated in these centers. With this review, we report the structure of the ARM-Net registry, some of the results, and discuss the challenges we faced and still face after its introduction in 2010.

Sexual function in adult patients with classic bladder exstrophy: A multicenter study

BACKGROUND

The bladder exstrophy-epispadias complex (BEEC) comprises a spectrum of congenital anomalies that represents the severe end of urorectal malformations, and has a profound impact on continence as well as sexual and renal functions.

OBJECTIVE

The relation between severity of BEEC and its associated functional impairments, on one hand, and the resulting restrictions in quality of life and potential psychopathology determine the patients' outcome. It is important for improving further outcome to identify BEEC-related sources of distress in the long term. Genital function and sexuality becomes an important issue for adolescent and adult BEEC individuals. Hence, the present study focused on sexual function and psychological adaption in patients with BEEC.

STUDY DESIGN

In a multicenter study 52 patients (13 females, 39 males) with classic bladder exstrophy (BE) with their bladders in use were assessed by a self-developed questionnaire about sexual function, and psychosexual and psychosocial outcome. The patients were born between 1948 and 1994 (median age 31 years).

RESULTS

Twelve of 13 (92%) females and 25 of 39 (64%) males with classic BE had answered the questions on sexual function. Of these, 50% females and 92% males answered that they masturbated. Females had sexual intercourse more frequently. Six (50%) females affirmed dyspareunia whereas only two (8%) males reported pain during erection. Eight (67%) females specified having orgasms. Eighteen (72%) males were able to ejaculate. Two males and none of the females lived in a committed partnership (Figure). Two (15%) females and 13 (33%) males answered all psychosocial questions. The majority of these patients had concerns about satisfactory sexuality and lasting, happy partnerships. A minority of patients of both sexes were willing to answer psychosocial questions. Sexual activity and relationships of many adult BE patients seems to be impaired. Not surprisingly, sexual activity and awareness were different in males and females even in a multi-organ anomaly.

DISCUSSION

To date, one of the main goals of the medical treatment of BEEC/BE patients is to enable normal sexual life and fertility. However, only a few outcome studies have focused on these issues with contradicting results, most of them not using standardized outcome measures. In accordance with other studies, our female BE patients have dyspareunia and most of our male BE patients were able to ejaculate. But the question of normal force of ejaculation, ejaculated volume, or semen analysis remains unanswered. Despite partial confirmation of previous findings, there is inconsistency referring to the outcome measured by the available studies. This might in part be explained by the fact that, other than this study, most previous studies are the result of single-institution experience. Thus, selection bias in the patient sampling due to different a clinical collective in different hospitals may be the consequence. Furthermore, patients' honesty and self-reflection in answering difficult questions regarding their sexual and cosmetic impairments is questionable. In addition, studies include a wide range of age groups and are connected with this life period. Fears and condition-specific anxieties might change over time. Hence, the strengths of this study are the nationwide and treating physician-independent data acquisition as well as the large sample size of adult patients with a very rare congenital malformation. Unfortunately, more detailed analyses on sexual function and current psychosocial situation, for example correlation of data with clinical symptoms such as continence status, was not possible as data were mainly not answered by patients.

CONCLUSION

To improve the quality of life of patients with BEEC/BE, treatment and follow-up should emphasize physical but also psychological care in these patients. Physicians should further re-evaluate their preconceptions and should take care of the patients throughout their lives.

Heterozygous FGF8 mutations in patients presenting cryptorchidism and multiple VATER/VACTERL features without limb anomalies

BACKGROUND

The acronym VATER/VACTERL association describes the combination of at least three of the following cardinal features: vertebral defects, anorectal malformations, cardiac defects, tracheoesophageal fistula with or without esophageal atresia, renal malformations, and limb defects. Although fibroblast growth factor-8 (FGF8) mutations have mainly found in patients with Kallmann syndrome, mice with a hypomorphic Fgf8 allele or complete gene invalidation display, aside from gonadotropin-releasing hormone deficiency, parts or even the entire spectrum of human VATER/VACTERL association.

METHODS

We performed FGF8 gene analysis in 49 patients with VATER/VACTERL association and 27 patients presenting with a VATER/VACTERL-like phenotype (two cardinal features).

RESULTS

We identified two heterozygous FGF8 mutations in patients displaying either VATER/VACTERL association (p.Gly29_Arg34dup) or a VATER/VACTERL-like phenotype (p.Pro26Leu) without limb anomalies. Whereas the duplication mutation has not been reported before, p.Pro26Leu was once observed in a Kallmann syndrome patient. Both our patients had additional bilateral cryptorchidism, a key phenotypic feature in males with FGF8 associated Kallmann syndrome. Each mutation was paternally inherited. Besides delayed puberty in both and additional unilateral cryptorchidism in one of the fathers, they were otherwise healthy. Serum hormone levels downstream the gonadotropin-releasing hormone in both patients and their fathers were within normal range.

CONCLUSION

Our results suggest FGF8 mutations to contribute to the formation of the VATER/VACTERL association. Further studies are needed to support this observation.

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.

First results of a European multi-center registry of patients with anorectal malformations

BACKGROUND

The European consortium on anorectal malformations (ARM-NET) was established to improve the health care of patients and to identify genetic and environmental risk factors. The aim of the present study was to present the first results on clinical data of a large European cohort of ARM patients based on our registry.

METHODS

In 2010, the registry was established including patient characteristics and data on diagnosis, surgical therapy, and outcome regarding complications. Patients born between 2007 and 2012 were retrospectively added. A descriptive analysis of this cohort was performed.

RESULTS

Two hundred and three ARM patients were included. Syndromes or chromosomal abnormalities were present in 9%. Perineal fistulas were seen most in boys (42%) and girls (29%). Rare forms of ARM were found in 4% of the male and in 14% of the female patients. Forty-five percent of the patients had additional urogenital abnormalities. However, 32% of the patients were never screened for bladder abnormalities. Eight percent were never screened for renal malformations. In the majority of patients (79%), a PSARP was performed for the definitive reconstruction.

CONCLUSION

This collaborative effort provides a representative basis to estimate incidence of ARM types, to discuss differences and similarities in treatment, and health consequences throughout Europe.

De novo 13q deletions in two patients with mild anorectal malformations as part of VATER/VACTERL and VATER/VACTERL-like association and analysis of EFNB2 in patients with anorectal malformations

Anorectal malformations (ARMs) comprise a broad spectrum of conditions ranging from mild anal anomalies to complex cloacal malformations. In 40-50% of cases, ARM occurs within the context of defined genetic syndromes or complex multiple congenital anomalies, such as VATER/VACTERL (vertebral defects [V], ARMs [A], cardiac defects [C], tracheoesophageal fistula with or without esophageal atresia [TE], renal malformations [R], and limb defects [L]) association. Here, we report the identification of deletions at chromosome 13q using single nucleotide polymorphism-based array analysis in two patients with mild ARM as part of VATER/VACTERL and VATER/VACTERL-like associations. Both deletions overlap the previously defined critical region for ARM. Heterozygous Efnb2 murine knockout models presenting with mild ARM suggest EFNB2 as an excellent candidate gene in this region. Our patients showed a mild ARM phenotype, closely resembling that of the mouse. We performed a comprehensive mutation analysis of the EFNB2 gene in 331 patients with isolated ARM, or ARM as part of VATER/VACTERL or VATER/VACTERL-like associations. However, we did not identify any disease-causing mutations. Given the convincing argument for EFNB2 as a candidate gene for ARM, analyses of larger samples and screening of functionally relevant non-coding regions of EFNB2 are warranted. In conclusion, our report underlines the association of chromosome 13q deletions with ARM, suggesting that routine molecular diagnostic workup should include the search for these deletions. Despite the negative results of our mutation screening, we still consider EFNB2 an excellent candidate gene for contributing to the development of ARM in humans.

De novo microduplications at 1q41, 2q37.3, and 8q24.3 in patients with VATER/VACTERL association

The acronym VATER/VACTERL association describes the combination of at least three of the following congenital anomalies: vertebral defects (V), anorectal malformations (A), cardiac defects (C), tracheoesophageal fistula with or without esophageal atresia (TE), renal malformations (R), and limb defects (L). We aimed to identify highly penetrant de novo copy number variations (CNVs) that contribute to VATER/VACTERL association. Array-based molecular karyotyping was performed in a cohort of 41 patients with VATER/VACTERL association and 6 patients with VATER/VACTERL-like phenotype including all of the patients' parents. Three de novo CNVs were identified involving chromosomal regions 1q41, 2q37.3, and 8q24.3 comprising one (SPATA17), two (CAPN10, GPR35), and three (EPPK1, PLEC, PARP10) genes, respectively. Pre-existing data from the literature prompted us to choose GPR35 and EPPK1 for mouse expression studies. Based on these studies, we prioritized GPR35 for sequencing analysis in an extended cohort of 192 patients with VATER/VACTERL association and VATER/VACTERL-like phenotype. Although no disease-causing mutation was identified, our mouse expression studies suggest GPR35 to be involved in the development of the VATER/VACTERL phenotype. Follow-up of GPR35 and the other genes comprising the identified duplications is warranted.

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.

Practice of dilatation after surgical correction in anorectal malformations

BACKGROUND

In order to prevent stricture of the neoanus after surgical correction, regular dilatation is recommended. There is a lack of knowledge about the performance of anal dilatation and the occurrence of pain. The aim of our investigation was to describe the practice of dilatation and to identify possible risk factors for painful procedures.

METHODS

Congenital Uro-Rectal Malformations Network is a German interdisciplinary multicenter research network. With standard questionnaires, physicians interviewed 243 patients and/or their parents at home, additional 103 patients born since 2009 were assessed through their treating physicians.

RESULTS

In total, 88 % of the patients received dilatations. Treatment lasted for 7 months in median (range 1-156 months), until the age of 13 months (range 1-171 months). In 69 % painful dilatation was reported; without a significant differences in age or gender. In 32 % bleeding was reported. In 30 % at least one dilatation was performed under general anesthesia. In 11 % some kind of analgesia was used. Type of fistula, dilatations lasting longer than 10 months and Hegar size above 15 were relevant factors for experience of pain. There were about 16 % postoperative strictures of the neoanus, without reported differences in dilatation procedures; but there was a relation to type of malformation.

CONCLUSION

Considering the high number of painful treatments, predictors for painful dilatations should be further clarified through standardized documentation and prospective evaluation in order to improve follow-up.

Assisted reproductive techniques and the risk of anorectal malformations: a German case-control study

BACKGROUND

The use of assisted reproductive techniques (ART) for treatment of infertility is increasing rapidly worldwide. However, various health effects have been reported including a higher risk of congenital malformations. Therefore, we assessed the risk of anorectal malformations (ARM) after in-vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI).

METHODS

Data of the German Network for Congenital Uro-REctal malformations (CURE-Net) were compared to nationwide data of the German IVF register and the Federal Statistical Office (DESTATIS). Odds ratios (95% confidence intervals) were determined to quantify associations using multivariable logistic regression accounting for potential confounding or interaction by plurality of births.

RESULTS

In total, 295 ARM patients born between 1997 and 2011 in Germany, who were recruited through participating pediatric surgeries from all over Germany and the German self-help organisation SoMA, were included. Controls were all German live-births (n = 10,069,986) born between 1997 and 2010. Overall, 30 cases (10%) and 129,982 controls (1%) were born after IVF or ICSI, which translates to an odds ratio (95% confidence interval) of 8.7 (5.9-12.6) between ART and ARM in bivariate analyses. Separate analyses showed a significantly increased risk for ARM after IVF (OR, 10.9; 95% CI, 6.2-19.0; P < 0.0001) as well as after ICSI (OR, 7.5; 95% CI, 4.6-12.2; P < 0.0001). Furthermore, separate analyses of patients with isolated ARM, ARM with associated anomalies and those with a VATER/VACTERL association showed strong associations with ART (ORs 4.9, 11.9 and 7.9, respectively). After stratification for plurality of birth, the corresponding odds ratios (95% confidence intervals) were 7.7 (4.6-12.7) for singletons and 4.9 (2.4-10.1) for multiple births.

CONCLUSIONS

There is a strongly increased risk for ARM among children born after ART. Elevations of risk were seen after both IVF and ICSI. Further, separate analyses of patients with isolated ARM, ARM with associated anomalies and those with a VATER/VACTERL association showed increased risks in each group. An increased risk of ARM was also seen among both singletons and multiple births.

Involvement of the WNT and FGF signaling pathways in non-isolated anorectal malformations: sequencing analysis of WNT3A, WNT5A, WNT11, DACT1, FGF10, FGFR2 and the T gene

Anorectal malformations (ARMs) comprise a broad spectrum of anomalies, including anal atresia, congenital anal fistula and persistence of the cloaca. Research suggests that genetic factors play an important role in ARM development. However, few genetic variants have been identified. Embryogenesis is orchestrated by crosstalk of the wingless-type MMTV integration site family (WNT) and fibroblast growth factor (FGF) signaling pathways in a process that involves several intracellular cascades. Studies in mice have implicated several genes from these pathways in the etiology of ARMs. We performed sequencing analysis of seven of these previously reported genes in 78 patients with ARMs occurring within the context of at least one additional congenital anomaly. No associations were identified with variants in WNT3A, WNT5A, WNT11, DACT1, FGF10 or the T gene. In the FGFR2 gene, three novel heterozygous nucleotide substitutions were identified. Further investigations, including the study of family members, revealed that these variants were not causally related to the phenotype in the present ARM cohort. Mutations in the seven investigated genes may nonetheless be a cause of ARMs in rare cases. However, further studies should consider genes encoding other proteins in the WNT/FGF signaling pathways as possible candidates.

Sexual function in adults with anorectal malformation: psychosocial adaptation. German Network for Congenital Uro-REctal Malformations (CURE-Net)

PURPOSE

The aim of the German Network for Congenital Uro-REctal Malformations (CURE-Net) is to collect data of affected patients with anorectal malformation (ARM) to investigate molecular causes, clinical implications and psychosocial outcome. The current issue was to examine sexual function and to explore psychosocial adaptation in adults with ARM.

METHODS

This qualitative study using narrative inquiry is part of a larger multi-center study of clinical queries and quality of life in patients with ARM. The guided interview focused on analysis of sexual function.

RESULTS

55 adult patients with ARM (23 females, 32 males, median age 23 years, range from 18 to 56 years) were investigated via standardized case-report forms comprising interview, analysis of medical data and personal questionnaires. In the female patients, 8 (35 %) of them lived alone and 15 (65 %) had sexual intercourse. In the male patients, the majority of 20 (69 %) patients lived alone and 13 (45 %) had sexual intercourse. 6 of the females got pregnant, 5 got 2 or more children. 3 of the men induced 2 or more pregnancies and fathered children.

CONCLUSION

Besides reconstructing the ARM, another main goal is the preservation of sexual function. According to our data, there seems to be a close relationship between psychosocial development and sexual activity.

Unexpected results of a nationwide, treatment-independent assessment of fecal incontinence in patients with anorectal anomalies

PURPOSE

To determine the anorectal function in patients with anorectal malformations (ARM) in order to facilitate patient counseling and follow-up.

METHODS

Data were collected by the German network for urorectal malformations (CURE-Net) according to the International Krickenbeck consensus. Questionnaires on bowel function and a defecation protocol were completed by the families/patients. The clinical findings were assessed from the patients' clinical records.

RESULTS

Two hundred and ninety-seven patients with ARM were assessed, 175 patients gave complete data on continence, 52 of them were excluded due to mental retardation, age, and earlier type of pullthrough. Complete continence was found in 27 %, perineal fistula in 40 %, rectourethral/vesical in 10 %, vestibular in 24 %, cloaca in 0 %. Krickenbeck grade 1 soiling: 42 %, grade 2 and 3: 31 %. Forty-nine percent of the incontinent patients practiced bowel management, reaching continence in 19 %. The statement of constipation (67 %) was validated with the last clinical findings, showing coprostasis in 46 %, "Not suffering constipation" was confirmed in 61 % and falsified in 29 %.

CONCLUSION

ARM patients in Germany, as assessed by independent researchers, show a high rate of fecal incontinence and insufficiently treated constipation. Parents should be counseled accordingly and motivated to engage in consequent follow-up. Intensified efforts in the conservative treatment of constipation and fecal incontinence are crucial to improvement.

Nine new twin pairs with esophageal atresia: a review of the literature and performance of a twin study of the disorder

BACKGROUND

Isolated esophageal atresia (EA) is a rare congenital malformation whose etiology remains largely unknown. Nine twin pairs with EA were identified from our clinical service, prompting the performance of a systematic review of the literature and the first reported twin study of isolated EA.

METHODS

A total of 330 twin pairs with EA were identified from the literature. The zygosity, concordance, and malformation (isolated vs. nonisolated) status of all 339 twin pairs were evaluated. A total of 72 twin pairs (4 of 9 / 68 of 330) fulfilled the criteria for inclusion in a classic twin study of isolated EA.

RESULTS

The pairwise concordance rates were 50% (95% confidence interval [CI], 34-66%) for monozygous (MZ) twin pairs and 26% (95% CI, 15-42%) for dizygous (DZ) twin pairs (p = 0.033). The probandwise concordance rates were 67% (95% CI, 53-78%) for MZ twin pairs and 42% (95% CI, 29-56%) for DZ twin pairs (p = 0.011). The MZ/DZ ratios were 1.9 for pairwise analysis and 1.6 for probandwise analysis. The familial risk ratios for MZ and DZ twin pairs were 1700 and 900, respectively.

CONCLUSION

The observation of higher concordance rates for MZ compared to DZ twin pairs indicates that genetic factors contribute to isolated EA.

De novo partial trisomy 18p and partial monosomy 18q in a patient with anorectal malformation

Anorectal malformations (ARM) encompass a broad clinical spectrum which ranges from mild anal stenosis to severe anorectal anomalies such as complex cloacal malformations. The overall incidence of ARM is around 1 in every 2,500 live births. Although causative genes for a few syndromic forms have been identified, the molecular genetic background of most ARM remains unknown. The present report describes a patient with a de novo 13.2-Mb deletion of chromosome 18q22.3-qter and a 2.2-Mb de novo duplication of chromosomal region 18pter-p11.32 located at the telomeric end of chromosome 18q. The patient presented with ARM and the typical features of 18q- syndrome (De-Grouchy syndrome). The combination of a partial duplication of the short arm and a partial deletion of the long arm of chromosome 18 has been described in 16 previous cases. However, this is the first report of an association between this complex chromosomal rearrangement and ARM.

Autosomal-dominant non-syndromic anal atresia: sequencing of candidate genes, array-based molecular karyotyping, and review of the literature

INTRODUCTION

Anorectal malformations (ARM) range from mild anal to severe anorectal anomalies. Approximately 50% are estimated to be non-syndromic with multiple familial cases reported that suggest underlying genetic factors. These, however, still await identification.

MATERIALS AND METHODS

We report a familial case of non-syndromic ARM with a mother and her two children being affected. Mother and daughter had mild ARM that had only been diagnosed after the index patient was born with a more severe form and ultrashort Hirschsprung's disease. To reveal the genetic cause in our family genome-wide array analysis was carried out to ascertain microaberrations characterized by loss or gain of genomic material. In addition, sequence analysis of four major Hirschsprung's disease genes (RET, EDNRB, EDN3, and GDNF) and the HLXB9 gene was performed to identify a mutation common to all three family members; however, these analyses did not reveal any causal genetic alteration. To demonstrate the frequency of familial non-syndromic cases, we performed a literature search revealing 59 families with at least two affected members. Sufficient description of ARM phenotype and affection status of relatives to surely classify them as familial non-syndromic forms was given for 22 families.

CONCLUSION

The present family suggests that mild ARM may be overlooked in patients with non-specific clinical symptoms and that the incidence of ARM may thus be higher than previously estimated. With the new possibilities of whole exome sequencing, even small families hold the possibility to identify causal defects.

Research perspectives in the etiology of congenital anorectal malformations using data of the International Consortium on Anorectal Malformations: evidence for risk factors across different populations

PURPOSE

The recently established International Consortium on Anorectal Malformations aims to identify genetic and environmental risk factors in the etiology of syndromic and nonsyndromic anorectal malformations (ARM) by promoting collaboration through data sharing and combined research activities.

METHODS

The consortium attempts to recruit at least 1,000 ARM cases. DNA samples are collected from case-parent triads to identify genetic factors involved in ARM. Several genetic techniques will be applied, including SNP arrays, gene and whole exome sequencing, and a genome-wide association study. Questionnaires inquiring about circumstances before and during pregnancy will be used to obtain environmental risk factor data.

RESULTS

Currently, 701 ARM cases have been recruited throughout Europe. Clinical data are available from all cases, and DNA samples and questionnaire data mainly from the Dutch and German cases. Preliminary analyses on environmental risk factors in the Dutch and German cohort found associations between ARM and family history of ARM, fever during first trimester of pregnancy and maternal job exposure to cleaning agents and solvents.

CONCLUSION

First results show that both genetic and environmental factors may contribute to the multifactorial etiology of ARM. The International Consortium on Anorectal Malformations will provide possibilities to study and detect important genes and environmental risk factors for ARM, ultimately resulting in better genetic counseling, improved therapies, and primary prevention.