Increased heritability of certain types of anorectal malformations

1q21.1 Duplication Syndrome and Anorectal Malformations: A Literature Review and a New Case

BACKGROUND

Anorectal malformations (ARMs) are a common pediatric surgical problem with an incidence of 1:1500 to 1:5000 live births. The phenotypical spectrum extends from anal stenosis to imperforate anus with or without anal fistula to persistent cloaca. They can manifest as either non-syndromic or syndromic conditions. Various environmental and genetic risk factors have been elucidated. The widespread use of genetic screening tests for the investigation of developmental disorders increased the recognition of copy number variants (CNVs) of the 1q21.1 region. Duplications have also been associated with a multitude of congenital anomalies, such as heart disease, short stature, scoliosis, urogenital, and ARMs, and they have also been found in healthy individuals. The aim of this manuscript is to contribute to the definition of the phenotype associated with 1q21.1 duplications.

CASE PRESENTATION

The present case describes a male, referred to us for an ARM, in whom array-comparative genomic hybridization (array-CGH) identified 1q21.1 duplication inherited from his healthy mother. No other genetic test was performed on the patient.

CONCLUSIONS

We propose considering genetic evaluation and analysis in patients with only one congenital malformation in order to eventually make an early diagnosis and a better quality of treatments.

Prenatal Exposure to Dibutyl Phthalate and Its Negative Health Effects on Offspring: In Vivo and Epidemiological Studies

Dibutyl phthalate (DBP) is a low-molecular-weight phthalate commonly found in personal care products, such as perfumes, aftershaves, and nail care items, as well as in children's toys, pharmaceuticals, and food products. It is used to improve flexibility, make polymer products soft and malleable, and as solvents and stabilizers in personal care products. Pregnancy represents a critical period during which both the mother and the developing embryo can be significantly impacted by exposure to endocrine disruptors. This article aims to elucidate the effects of prenatal exposure to DBP on the health and development of offspring, particularly on the reproductive, neurological, metabolic, renal, and digestive systems. Extensive research has examined the effects of DBP on the male reproductive system, where exposure is linked to decreased testosterone levels, reduced anogenital distance, and male infertility. In terms of the female reproductive system, DBP has been shown to elevate serum estradiol and progesterone levels, potentially compromising egg quality. Furthermore, exposure to this phthalate adversely affects neurodevelopment and is associated with obesity, metabolic disorders, and conditions such as hypospadias. These findings highlight how urgently stronger laws prohibiting the use of phthalates during pregnancy are needed to lower the risks to the fetus's health and the child's development.

Spatial transcriptomics reveals gene interactions and signaling pathway dynamics in rat embryos with anorectal malformation

Anorectal malformation (ARM) is a prevalent early pregnancy digestive tract anomaly. The intricate anatomy of the embryonic cloaca region makes it challenging for traditional high-throughput sequencing methods to capture location-specific information. Spatial transcriptomics was used to sequence libraries of frozen sections from embryonic rats at gestational days (GD) 14 to 16, covering both normal and ARM cases. Bioinformatics analyses and predictions were performed using methods such as WGCNA, GSEA, and PROGENy. Immunofluorescence staining was used to verify gene expression levels. Gene expression data was obtained with anatomical annotations of clusters, focusing on the cloaca region's location-specific traits. WGCNA revealed gene modules linked to normal and ARM cloacal anatomy development, with cooperation between modules on GD14 and GD15. Differential gene expression profiles and functional enrichment were presented. Notably, protein levels of Pcsk9, Hmgb2, and Sod1 were found to be downregulated in the GD15 ARM hindgut. The PROGENy algorithm predicted the activity and interplay of common signaling pathways in embryonic sections, highlighting their synergistic and complementary effects. A competing endogenous RNA (ceRNA) regulatory network was constructed from whole transcriptome data. Spatial transcriptomics provided location-specific cloaca region gene expression. Diverse bioinformatics analyses deepened our understanding of ARM's molecular interactions, guiding future research and providing insights into gene regulation in ARM development.

CircJag1 promotes apoptosis of ethylene thiourea-exposed anorectal malformations through sponging miR-137-3p by regulating Sox9 and suppressing Wnt/β-catenin pathway during the hindgut development of rat embryos

Anorectal malformations (ARMs) are common birth defects involving congenital structural anomalies of the gastrointestinal tract. As an important component of non-coding RNAs, circular RNAs (circRNAs) widely participate in the digestive system development; however, the specific molecular mechanism of their involvement in ARM occurrence remains obscure. Herein, we generated rat models of ARMs induced by ethylene thiourea. A novel circRNA (circJag1) was screened and identified by RNA-Seq, which is remarkably upregulated in hindgut tissues of ARM rat embryos. In vivo experiments, colocation analysis via fluorescence in situ hybridization, and immunofluorescence further demonstrated that the disordered circJag1/miR-137-3p/Sox9 expression caused a spatiotemporal imbalance in the urorectal septum (URS) of ARMs. In vitro, functional assays confirmed that circJag1 upregulation resulted in the degradation of nuclear β-catenin, C-myc, and Cyclin D1 in rat intestinal epithelial cells, as well as the promotion of apoptosis and suppression of cell proliferation. Mechanistically, dual-luciferase reporter assay and RNA immunoprecipitation assay indicated that circJag1 acted as a miR-137-3p sponge, thereby inhibiting its repressive effect on its target Sox9. Further experiments showed that a loss of Sox9 abolished the circJag1-mediated increase in apoptosis. In conclusion, aberrantly high circJag1 expression promotes epithelial apoptosis by suppressing the canonical Wnt/β-catenin pathway via the miR-137-3p/Sox9 axis, which leads to fusion failure of the URS and cloacal membrane, and eventually contributed to ARMs. Our achievements might boost the comprehension of ARM pathogenesis and could provide a novel candidate target for the development of therapies for ARMs to complement surgical treatment.

Embryology and anatomy of anorectal malformations

The etiology of anorectal malformations (ARM) is complicated because of the spectrum of anomalies seen clinically, many of which are isolated and seemingly unique. Recent studies suggest that ARMs result from abnormal cloacal membrane (CM) development that contributes to disrupt normal local muscle and nerve development. If CM maldevelopment is severe, the rectal pouch lies above the pelvic floor, resulting in asymmetric and/or deviated musculature, so a midline incision is likely to cause trauma or be detrimental. Autonomic nerve plexuses can be associated with a fistula tract in ARMs and are also at risk for damage during surgery and contribute to genitourinary complications. Understanding the anatomy and development of the perineum is crucial for treating the broad spectrum of anomalies associated with ARMs and may assist in predicting/managing other related morbidity.

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.

Congenital anomalies of the tubular gastrointestinal tract

Congenital anomalies of the tubular gastrointestinal tract are an important cause of morbidity not only in infants, but also in children and adults. The gastrointestinal (GI) tract, composed of all three primitive germ layers, develops early during embryogenesis. Two major steps in its development are the formation of the gut tube (giving rise to the foregut, the midgut and the hindgut), and the formation of individual organs with specialized cell types. Formation of an intact and functioning GI tract is under strict control from various molecular pathways. Disruption of any of these crucial mechanisms involved in the cell-fate decision along the dorsoventral, anteroposterior, left-right and radial axes, can lead to numerous congenital anomalies, most of which occur and present in infancy. However, they may run undetected during childhood. Therapy is surgical, which in some cases must be performed urgently, and prognosis depends on early diagnosis and suitable treatment. A precise pathologic macroscopic or microscopic diagnosis is important, not only for the immediate treatment and management of affected individuals, but also for future counselling of the affected individual and their family. This is even more true in cases of multiple anomalies or syndromic patterns. We discuss some of the more frequent or clinically important congenital anomalies of the tubular GI, including atresia's, duplications, intestinal malrotation, Meckel's diverticulum and Hirschsprung's Disease.

Genetic Counseling and Diagnostics in Anorectal Malformation

Anorectal malformation (ARM) is a relatively frequently occurring congenital anomaly of hindgut development with a prevalence of 1 in 3,000 live births. ARM may present as an isolated anomaly, but it can also be associated with other anomalies, sometimes as part of a recognizable syndrome. After birth, much medical attention is given to the treatment and restoring of bowel function in children with ARM. Effort should also be given to studying the etiology of the ARM in these patients. This information is important to both the medical community and the family, because it can help guide treatment and provides information on the long-term prognosis of the patient and recurrence risk in the family.In this article, we will review the current knowledge on the (genetic) etiology of (syndromic) ARM and provide guidelines for (family) history taking and clinical and genetic studies of ARM patients and their families, which is needed to study the causal factors in an ARM patient and for genetic counseling of the families.

Risk factors of vesicoureteral reflux and urinary tract infections in children with imperforate anus: A population-based case-control study in Taiwan

Imperforate anus (IA) is associated with several urological anomalies, including vesicoureteral reflux (VUR), a major contributor to high morbidity in patients with anorectal malformations. This retrospective study was performed to elucidate the risk factors of vesicoureteral reflux (VUR) and UTI in children with IA.We used the National Health Insurance Research Database (NHIRD) to estimate the frequency of congenital anomalies of the kidney and urinary tract (CAKUT) in children with IA. We also investigated the frequencies of VUR, UTI, and CAKUT in children with IA along with the risk factors of VUR.We enrolled 613 children between 2000 and 2008 (367 males and 246 females; 489 low-position IA and 124 high-position IA). High-position IA was associated with a significantly increased risk of VUR compared with low-position IA (OR: 2.68, 95% CI: 1.61, 4.45). In addition, children with IA along with CAKUT, hydronephrosis, or UTI had a higher risk of VUR (OR: 8.57, 95% CI: 3.75, 19.6; OR: 7.65, 95% CI: 4.48, 13.1; and OR: 31.8, 95% CI: 11.5, 88.3, respectively). UTI, as well as chromosomal anomalies, were more frequent in children with high-position IA.Patients with a high-position IA had a greater risk of VUR, particularly those with CAKUT, hydronephrosis, or UTI. Such patients must periodically undergo urinalysis to screen for UTI and early voiding cystourethrogram to rule out VUR and prevent consequent renal damage. Chromosomal analysis is suggested to rule out Down syndrome.

Case report: a de-novo 7p12.3 microduplication detected in an infant with perineal hamartoma and imperforate anus

Background

Anorectal malformations (ARM) represent a wide spectrum of defects. Caudal and genitourinary malformations can associate with anorectal malformations. Genetic factors may play role in the development of anorectal malformations. Perineal masses like sacrococcygeal teratoma, rectal prolapse, or duplication cysts were reported before, but their association with perineal hamartoma and anal atresia is extremely rare.

Case presentation

Here, we report an 11-month-old female infant. She had 551 kb duplication at 7p12.3 with perineal hamartoma and anal atresia consisting a cystic lesion with a diameter of 4 mm at the filum terminale (L2 vertebra) on lumbar magnetic resonance imaging (MRI) in neonatal period. She presented with hypotonia. She had anorectal anomaly and external perineal mass bulging from left major labium extending across anal region with imperforate anus. There was 1 × 1 cm polyp-like protrusion on it. She was operated in neonatal period. Genetic laboratory investigations showed karyotype 46, XX. The microduplication of the chromosome 7p12.3 was detected by microarray analysis. There were not any significant homozygous or heterozygous variants determined  by whole-exome sequencing.

Conclusions

To the best of our knowledge, this is the first report of a patient with a microduplication of the chromosome 7p12.3, and second case with perineal hamartoma and imperforate anus. Clinicians should pay attention to microdeletions and microduplications while giving genetic counseling to patients with urogenital and anorectal abnormalities.

The Role of De Novo Variants in Formation of Human Anorectal Malformations

Anorectal malformations (ARM) represent a rare birth defect of the hindgut that occur in approximately 1 in 3000 live births. Around 60% of ARM occur with associated anomalies including defined genetic syndromes and associations with chromosomal aberrations. The etiology of ARM is heterogeneous, with the individual environmental or genetic risk factors remaining unknown for the majority of cases. The occurrence of familial ARM and previous epidemiologic analysis suggest autosomal dominant inheritance in a substantial subset of ARM patients. The implicated mortality and reduced fecundity in patients with ARM would lead to allele loss. However, mutational de novo events among the affected individuals could compensate for the evolutionary pressure. With the implementation of exome sequencing, array-based molecular karyotyping and family-based rare variant analyses, the technologies are available to identify the respective factors. This review discusses the identification of disease-causing variants among individuals with ARM. It highlights the role of mutational de novo events.

Upregulation of PPPDE1 contributes to anorectal malformations via the mitochondrial apoptosis pathway during hindgut development in rats

Congenital anorectal malformations (ARMs) are among the most prominent deformities of the gastrointestinal tract; however, their precise aetiology remains obscure. Immunohistochemistry demonstrated that, in the ARM group, the PPPDE1-positive cells were widely distributed in the hindgut epithelial tissue from GD13 to GD16. Immunofluorescence revealed that most TUNEL-, Bax-, and Cytochrome C (Cyt C)-positive cells overlapped with PPPDE1-positive cells in the urorectal septum (URS). Western blotting and quantitative real-time RT-PCR revealed that PPPDE1 levels were significantly higher in the ARM group from GD13 to GD14 (p < 0.05). IEC-6 cells were transfected with PPPDE1 overexpression plasmid/NC (negative control) or si-PPPDE1/si-NC. Flow cytometry analysis and CCK-8 assay (used to detect apoptosis and proliferation, respectively), as well as western blotting, showed that the levels of PPPDE1 were positively correlated with the pro-apoptotic molecules Bax and Cyt C. Accordingly, aberrantly high expression of PPPDE1 caused a spatiotemporal imbalance in foetal rats with ARMs during hindgut development. Therefore, the upregulation of PPPDE1 may promote epithelial apoptosis and reduce proliferation in the hindgut via the mitochondrial apoptotic pathway. This could affect the fusion of the URS and cloacal membrane, ultimately inhibiting the hindgut development and resulting in ARMs.

Risk factors for anorectal and associated malformations in German children: A 10-year analysis

BACKGROUND

Incidences of anorectal malformations (ARM) occur in 1 of 2000-5000 live births and up to 64% have associated malformations (ARMa). The aim of the study was to evaluate possible prenatal risk factors for ARM in a tertiary hospital.

METHODS

A case-control design was used to compare risk factors in ARM (n = 44) to a control group (CG; n = 26). We used modified prenatal questionnaires, analyzed mothers' prenatal records and participants completed a structured interview. Endpoints were medical history, drug consumption, occupational risk factors, and time point of diagnosis, associated malformations and sensitivity of radiological imaging.

RESULTS

Our results showed that ARM couples had a significantly higher age difference (p = 0.028) compared to CG. ARM mothers had more abnormalities during pregnancy (p = 0.002), more positive vaginal smears of group B streptococci (p = 0.024), urogenital infections (p = 0.005), gestosis (p = 0.03), emesis (p = 0.025) and higher numbers of chronic diseases (p = 0.018). ARM mothers took less medication during pregnancy (p = 0.013) than CG mothers including folic acid (p = 0.041); their intake of iodine tablets was significantly higher (p = 0.035) and they continued smoking for longer (p = 0.036) than CG mothers, and they had more stillbirths (p = 0.035). In using illegal drug and alcohol use, the groups did not show significant differences. ARMa was present in 68.1% (n = 30), of which 45.5% were of urogenital origin (n = 20). ARM diagnosis was made on the first day of life in 72.7% (n = 32), while diagnosis was delayed in 12 patients (27.3%).

CONCLUSION

A combination of different risk factors seem to be associated with the development of ARM, which takes place at an early stage (<7th week) of pregnancy. Therefore, risk factors influencing fetal development must be critically considered. We advocate an interdisciplinary assessment in unclear clinical findings on first day of life to optimize the therapy and positively influence the outcome.

Comparison of Maternal Histories and Exposures in Children With Isolated Anorectal Malformation Versus Anorectal Malformation With Genitourinary Anomalies

Introduction

To our knowledge, there are no studies to date that have compared patients with isolated anorectal malformation (ARM) to patients with ARM and an associated genitourinary (GU) malformation despite a possible etiological difference between these two entities. We examined the differences in maternal and prenatal exposures and comorbidities between patients with isolated ARM and patients with ARM and associated GU malformations.

Materials and methods

A retrospective cohort study of children with ARM, enrolled in the Pediatric Colorectal and Pelvic Learning Consortium (PCPLC) between February 2017 and October 2019, was performed comparing those with isolated ARM to those with ARM and associated GU anomalies (GU +/- additional anomalies) as well as to those with ARM and a GU anomaly with no anomaly of any other system (GU-only). We compared the prevalence of prematurity, family history of colorectal disorders, as well as maternal and prenatal comorbidities and exposures between these two cohorts and the isolated ARM cohort.

Results

A total of 505 patients (117 with isolated ARM and 388 with ARM and associated GU anomalies) were enrolled. Of the 388 patients with ARM and associated GU anomalies, 48 had an ARM with a GU anomaly without an anomaly in any other system. There was an increased prevalence of premature births in the GU +/- additional anomalies cohort compared to the isolated ARM cohort (27 vs 14%, p=0.003). This difference was not seen in the GU-only cohort. There was no difference between the cohorts regarding prevalence of family history of ARM or maternal and prenatal comorbidities or exposures.

Conclusions

Patients with an ARM and an associated GU anomaly with or without other congenital anomalies are more likely to be born prematurely compared to patients with an isolated ARM. Parents of these children should be counseled on this increased risk.

Exome chip association study excluded the involvement of rare coding variants with large effect sizes in the etiology of anorectal malformations

INTRODUCTION

Anorectal malformations (ARM) are rare congenital malformations, resulting from disturbed hindgut development. A genetic etiology has been suggested, but evidence for the involvement of specific genes is scarce. We evaluated the contribution of rare and low-frequency coding variants in ARM etiology, assuming a multifactorial model.

METHODS

We analyzed 568 Caucasian ARM patients and 1,860 population-based controls using the Illumina HumanExome Beadchip array, which contains >240,000 rare and low-frequency coding variants. GenomeStudio clustering and calling was followed by re-calling of 'no-calls' using zCall for patients and controls simultaneously. Single variant and gene-based analyses were performed to identify statistically significant associations, applying Bonferroni correction. Following an extra quality control step, candidate variants were selected for validation using Sanger sequencing.

RESULTS

When we applied a MAF of ≥1.0%, no variants or genes showed statistically significant associations with ARM. Using a MAF cut-off at 0.4%, 13 variants initially reached statistical significance, but had to be discarded upon further inspection: ten variants represented calling errors of the software, while the minor alleles of the remaining three variants were not confirmed by Sanger sequencing.

CONCLUSION

Our results show that rare and low-frequency coding variants with large effect sizes, present on the exome chip do not contribute to ARM etiology.

Atresia Ani with Imperforate Anus in a Common Marmoset (Callithrix jacchus)

In November 2015, an 83-d-old juvenile male common marmoset (Callithrix jacchus) in good body condition was found dead in his family cage with no previous premonitory signs. Necropsy revealed a gas-distended abdomen, feces-distended large bowel, and a full-thickness distal colonic perforation resulting in fecal peritonitis. The distal colon ended in a blind pouch at 7 mm prior to the expected anal opening, consistent with atresia ani. Here we present this case, briefly discuss the human and veterinary literature regarding correction of anorectal malformations, and highlight the importance of identifying such devastating congenital defects in breeding colonies while limiting the disruption and handling of seemingly healthy, young NHP raised in a complex social setting.

Associated anomalies in cases with anorectal anomalies

Anorectal anomalies (ARA) are common congenital anomalies. The etiology of ARA is unclear and its pathogenesis is controversial. Cases with ARA often have other non-ARA-associated congenital anomalies. The purpose of this study was to assess the prevalence and the types of these associated anomalies in a defined population. The associated anomalies in cases with ARA were collected in all live births, stillbirths, and terminations of pregnancy during 29 years in 387,067 consecutive births in the area covered by our population-based registry of congenital malformations. Of the 202 cases with ARA, representing a prevalence of 5.21 per 10,000, 100 (49.5%) had associated anomalies. There were 7 (3.3%) cases with chromosomal abnormalities, and 31 (15.3%) nonchromosomal recognized dysmorphic conditions, including 17 cases with Vertebral defects, Anal atresia, Cardiac septal defects, esophageal atresia or TracheoEsophageal fistula, Renal anomalies and radial Limb defects association. Sixty two (30.7%) of the cases had nonsyndromic multiple congenital anomalies (MCA). Anomalies in the urogenital, the musculoskeletal, the cardiovascular, the digestive, and the central nervous systems were the most common other anomalies in the cases with MCA. The anomalies associated with ARA could be classified into a recognizable malformation syndrome or pattern in 38 out of the 100 cases (38%) with associated anomalies. This study included special strengths: each affected child was examined by a geneticist, all elective terminations were ascertained, and the surveillance for anomalies was continued until 2 years of age. In conclusion, the overall prevalence of associated anomalies, which was close to one in two cases, emphasizes the need for a routine screening for other anomalies in cases with ARA.

Maternal drug use and the risk of anorectal malformations: systematic review and meta-analysis

Background

Origin of anorectal malformations (ARM) are considered multifactorial. Several genetic and non-genetic risk factors are discussed in literature. Maternal periconceptional medical drug use as possible risk factor, however, has not been reviewed systematically.

Methods

Studies published between 1977 and April 2017 were reviewed through systematic search in PubMed, ISI Web of Knowledge and Scopus databases. Furthermore, related and cross-referencing publications were reviewed. Pooled odds ratios (95% confidence intervals) were determined to quantify associations of maternal periconceptional use of folic acid, multivitamins, anti-asthma medication (separated in any anti-asthma medication, inhaled corticosteroids and salbutamol), thyroid hormone supplements, psychiatric drugs (separated in antidepressants, any selective serotonin reuptake inhibitors [SSRI], sertraline, citalopram, fluoxetine, paroxetine, hypnotics and benzodiazepine) and aspirin with ARM using meta-analyses.

Results

Thirty-seven studies that reported on the association between maternal periconceptional drug intake and infants born with ARM were included in this review. These were conducted in the United States of America (n = 14), Sweden (n = 6), Hungary (n = 5), Germany (n = 3), the Netherlands (n = 3), Denmark (n = 2), France (n = 2), Norway (n = 1) and the UK (n = 1). However, only few of these studies reported on the same risk factors. Studies were heterogeneous with respect to case numbers, period ingestion of medical drug use, control selection and adjustment for covariates. Consistently increased risks were observed for any anti-asthma medication, and hypnotics and benzodiazepine, but not for folic acid, multivitamins, inhaled corticosteroids, salbutamol, thyroid hormone supplements, antidepressants, any SSRI, sertraline, citalopram, fluoxetine, paroxetine and aspirin. In meta-analyses, pooled odds ratios (95% confidence intervals) for any anti-asthma medication, and hypnotics and benzodiazepine were 1.64 (1.22–2.21), and 2.43 (1.03–5.73), respectively.

Conclusion

Evidence on maternal drug use before conception and during pregnancy as risk factor for ARM from epidemiological studies is still very limited. Nevertheless, the few available studies indicate any anti-asthma medication, and hypnotics and benzodiazepine to be associated with increased risks. Further, ideally large-scale multicenter and register-based studies are needed to clarify the role of maternal drug intake for the development of ARM.

Anorectal Malformations

Anorectal malformation are common congenital problems occurring in 1 in 5,000 births and have a spectrum of anatomical presentations, requiring individualized treatments for the newborn, sophisticated approaches to the definitive reconstruction, and management of long-term treatments and outcomes. Associated anomalies related to the cardiac, renal, gynecologic, orthopedic, spinal, and sacral systems impact care and prognosis. Long-term results are good provided there is an accurate anatomical reconstruction and a focus on maximizing of functional results.

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.

Transition of care in patients with anorectal malformations: Consensus by the ARM-net consortium

OBJECTIVES

To develop the first consensus to standardize the management of patients with Anorectal Malformations (ARMs) transitioning from childhood to adulthood.

METHODS

A dedicated task force of experts performed an extensive literature review and multiple meetings to define the most important aspects of transition of care. The findings were discussed with all ARM-net consortium members and a set of practical recommendations agreed upon at the annual meeting in 2016.

RESULT

We defined seven domains that are essential to provide an effective and practical transition process. Within each domain we have developed a set of key recommendations that are important to be considered for ARM patients entering the age of transition.

CONCLUSIONS

It is crucial that transition begins at an early age with regular and well-structured follow-up. Cooperation with a selected multidisciplinary team of pediatric and adult practitioners is required to prepare patients and families for effective transition to adult care and to reduce long term morbidity.

TYPE OF STUDY

Review/Consensus paper.

LEVEL OF EVIDENCE

III.

Spatiotemporal expression of proprotein convertase subtilisin/kexin type 5 in the development of anorectal malformations in fetal rats

This study examined the expression patterns of proprotein convertase subtilisin/kexin type 5 (Pcsk5) during anorectal development in normal and anorectal malformations (ARM) rat embryos, determine the possible role of Pcsk5 in the pathogenesis of ARM. An ARM rat model was developed by the administration of ethylenethiourea gestational day 10 (GD10). Embryos were harvested by surgical excision from GD13 to GD16, and the spatiotemporal expression of Pcsk5 was evaluated, using immunohistochemistry staining, Western blotting and real time RT-PCR. Immunohistochemistry staining in normal embryos revealed that Pcsk5 was abundantly expressed on the epithelium of the cloaca (CL) on GD13. On GD14 and GD15, positive cells were noted on the urorectal septum and the thin anal membrane. However, the epithelium of the CL of ARM embryos only faintly expressed Pcsk5 from GD13 to GD15. Western blotting and real time RT-PCR showed time-dependent increase of Pcsk5 expression in the developing hindgut. Pcsk5 expression levels were lower in the ARM group from GD14 to GD16 (p ≤ 0.05). These results indicate that downregulation of Pcsk5 during cloaca development into the rectum and urethra might be related to the formation of ARMs.

Genetic research and structural dysplasia assessment of anorectal malformations in neonatal male rats induced by di(n-butyl) phthalate

This study was the first to investigate the genetic abnormalities and structural dysplasia of anorectal malformations (ARMs) in male rats induced by di(n-butyl) phthalate (DBP). DBP was administered to timed-pregnant rats to establish the ARM rat model. The incidence of ARMs in male offspring was 39.5%. In neonatal period, decreased body weight and anogenital distance were observed. The general image and histological analysis of male offspring confirmed the presence of ARMs. Anatomical examination of the ARM male rats revealed the dysplasia in solid organs (heart-lung, liver, spleen, and kidney). The decreases of serum testosterone concentration and androgen receptor expression in terminal rectum were indicative of the antiandrogenic effects of DBP. Moreover, significant decreased mRNA expressions of these androgen-related genes such as sonic hedgehog, Gli2, Gli3, bone morphogenetic protein 4, Wnt5a, Hoxa13, Hoxd13, fibroblast growth factor 10, and fibroblast growth factor receptor 2 were found in terminal rectum of the ARM male pubs. These results demonstrated that development of ARM rats was impaired by maternal exposure to DBP. The antiandrogenic effects of DBP disturbing the androgen-related signaling networks might play an important role in the occurrence of ARMs.

Parental risk factors of anorectal malformations: Analysis with a regional population-based control group

BACKGROUND

Adequate evidence on environmental risk factors for anorectal malformations (ARMs) is very limited. We assessed maternal body weight and several prenatal exposures of the parents to tobacco, pregestational diabetes, chronic cardiovascular and respiratory diseases, periconceptional folic acid and multivitamin intake.

METHODS

Data from the German Network for Congenital Uro-REctal malformations (CURE-Net) were compared with data from the Malformation Monitoring Centre Saxony-Anhalt of the Otto-von-Guericke University in Magdeburg, Germany. Controls were matched to cases by gender and birth year of the child. Crude and adjusted odds ratios (95% confidence intervals) were calculated for potential risk factors using multivariable logistic regression.

RESULTS

In total, 158 ARM patients and 474 healthy infants born between 1993 and 2008 in Germany were included. Maternal age at birth of ARM cases and birth plurality were significantly higher and gestational age and weight significantly lower compared with controls (p < 0.0001). We observed significantly increased risks for ARMs associated with maternal smoking before conception and the first trimester of pregnancy (odds ratio = 2.23, 95% confidence interval 1.04-4.79, p = 0.039) and maternal chronic respiratory diseases (odds ratio = 29.25, 95% confidence interval 8.22-104.14, p < 0.0001). No statistically significant increased risk or protective effect was found for the other investigated factors.

CONCLUSION

This study suggests an association between the occurrence of ARMs in the offspring and periconceptional maternal smoking as well as maternal chronic respiratory diseases. In addition, there might be a sign of an association for maternal diabetes, although not statistically significant. It can be assumed that the power is far too low to provide reliable estimates.

Parental subfertility, fertility treatment, and the risk of congenital anorectal malformations

BACKGROUND

Fertility treatment seems to play a role in the etiology of congenital anorectal malformations, but it is unclear whether the underlying parental subfertility, ovulation induction, or the treatment itself is involved. Therefore, we investigated the odds of anorectal malformations among children of subfertile parents who conceived with or without treatment compared with fertile parents.

METHODS

We performed a case-control study among 380 cases with anorectal malformations treated at 3 departments of pediatric surgery in The Netherlands and 1973 population-based controls born between August 1988 and August 2012. Parental questionnaires were used to obtain information on fertility-related issues and potential confounders.

RESULTS

In singletons, increased risks of anorectal malformations were observed for parents who underwent intracytoplasmic sperm injection (ICSI) or in vitro fertilization (IVF) treatment compared with fertile parents (odds ratio = 2.4 [95% confidence interval = 1.0-5.9] and 4.2 [1.9-8.9], respectively). For subfertile parents who conceived after IVF treatment, an elevated risk was also found when they were compared with subfertile parents who conceived without treatment (3.2 [1.4-7.2]). Among children of the latter category of parents, only the risk of anorectal malformations with other major congenital malformations was increased compared with fertile parents (2.0 [1.3-3.3]). No associations were found with intrauterine insemination or use of hormones for ovulation induction.

CONCLUSIONS

We found evidence of a role of ICSI and IVF treatments in the etiology of anorectal malformations. However, subfertility without treatment increased only the risk of anorectal malformations with additional congenital malformations.

Genetic and nongenetic etiology of nonsyndromic anorectal malformations: a systematic review

Congenital anorectal malformations (ARMs) are one of the most frequently observed birth defects of the digestive system. However, their etiology remains elusive. Therefore, we aim to summarize and critically appraise all existing literature on the genetic and nongenetic etiology of nonsyndromic ARM and to conclude with unifying hypotheses and directions for future research. A structured literature search on English language human studies was conducted in PubMed and Embase up to October 1, 2013, resulting in 112 included articles. Research on the identification of genes underlying nonsyndromic ARM is remarkably scarce. Most studies were focused on screening of candidate genes for mutations or single-nucleotide polymorphisms, which did not yield any substantial evidence. Nongenetic factors fairly consistently found to be associated with ARM are assisted reproductive techniques, multiple pregnancy, preterm delivery, low birth weight, maternal overweight or obesity, and preexisting diabetes. This review provides indications for the involvement of both genes and nongenetic risk factors in the etiology of ARM. In future studies, large cohorts of patients with ARM from national and international collaborations are needed to acquire new hypotheses and knowledge through hypothesis-generating approaches. Challenges for future studies may also lie in the investigation of gene-gene and gene-environment interactions.

Expression of the Shh/Bmp4 signaling pathway during the development of anorectal malformations in a male rat model of prenatal exposure to di(n-butyl) phthalate

Sonic hedgehog (Shh)/bone morphogenetic protein 4 (Bmp4) is an androgen-regulated signaling pathway that has been shown to be crucial for embryonic development.

The Great Divide: Understanding Cloacal Septation, Malformation, and Implications for Surgeons

The anorectal and urogenital systems arise from a common embryonic structure termed cloaca. Subsequent development leads to the division/septation of the cloaca into the urethra, urinary bladder, vagina, anal canal, and rectum. Defective cloacal development and the resulting anorectal and urogenital malformations are some of the most severe congenital anomalies encountered in children. In the most severe form in females, the rectum, vagina, and urethra fail to develop separately and drain via a single common channel known as a cloaca into the perineum. In this review, we summarize our current knowledge of embryonic cloaca development and malformation, and compare them to what has already been described in the literature. We describe the use of mouse models of cloaca malformation to understand which signaling pathways and cellular mechanisms are involved in the process of normal cloaca development. We also discuss the embryological correlation of the epithelial and stromal histology found in step sections of the common channel in 14 human cloaca malformations. Finally, we highlight the significance of these findings, compare them to prior studies, and discuss their implications for the pediatric surgeons. Understanding and identifying the molecular basis for cloaca malformation could provide foundation for tissue engineering efforts that in the future would reflect better surgical reconstruction and improved quality of life for patients.

Hypermethylation of SHH in the pathogenesis of congenital anorectal malformations

OBJECTIVE

This study sought to examine promoter methylation and expression of the identified sonic hedgehog (SHH) gene in terminal rectal tissues of children with congenital anorectal malformations (ARMs).

METHODS

Tissue samples from the terminal rectum of pediatric patients with ARMs (five cases each of high and intermediate malformation - two cases of rectovesical fistula, two cases of rectourethral prostatic fistula, one case of cloaca with >3cm common channel, four cases of rectourethral bulbar fistula and one case of imperforate anus without fistula, respectively, and ten cases of low malformation - five cases of perineal fistula and five cases of vestibular fistula, respectively), and patients with non-gastrointestinal tract malformation (six cases, anal fistula) were collected and divided into three groups: high-intermediate ARM (ARMhi-int), low ARM (ARMlo), and control (Cont.). Real-time RT-PCR was used to detect mRNA expression levels of the verified differentially methylated gene SHH, and bisulfite genomic sequencing was performed to evaluate DNA methylation in the SHH promoter region.

RESULTS

The average methylation levels of the SHH promoter were significantly higher in ARMhi-int (0.850±0.030, P=0.0036) and ARMlo (0.540±0.053, P=0.0087) groups than in Cont. group (0.280±0.032). SHH mRNA expression levels were lower in ARMhi-int (0.340±0.015, P=0.0065) and ARMlo (0.530±0.042, P=0.0156) groups than in Cont. group (0.870±0.046). The average methylation levels of the SHH promoter were higher in ARMhi-int group than in ARMlo group (0.850±0.030 vs. 0.540±0.053, P=0.0095), while SHH expression was significantly reduced in ARMhi-int group compared to ARMlo group (0.340±0.15 vs. 0.530±0.042, P=0.0252). The methylation levels of the SHH promoter in ARMhi-int group were negatively correlated with SHH gene expression (r=-0.89, P<0.01).

CONCLUSIONS

The SHH gene, which plays a major role in the development of the anorectum and enteric nervous system, is hypermethylated at its promoter, and this is correlated with low levels of SHH gene expression. This epigenetic modification may therefore be responsible for the observed changes in SHH expression, which could in turn underlie the pathogenesis of congenital ARMs.

No major role for periconceptional folic acid use and its interaction with the MTHFR C677T polymorphism in the etiology of congenital anorectal malformations

BACKGROUND

Both genetic and nongenetic factors are suggested to be involved in the etiology of congenital anorectal malformations (ARM). Maternal periconceptional use of folic acid supplements were inconsistently suggested to play a role in the prevention of ARM. Therefore, we investigated independent associations and interactions of maternal periconceptional folic acid supplement use and the infant and maternal MTHFR (methylenetetrahydrofolate reductase) C677T polymorphisms with the risk of ARM and subgroups of ARM.

METHODS

A case-control study was conducted among 371 nonsyndromic ARM cases and 714 population-based controls born between 1990 and 2012 using maternal questionnaires and DNA samples from mother and child. Cases were treated for ARM at departments of Pediatric Surgery of the Radboud university medical center, Sophia Children's Hospital-Erasmus MC Rotterdam, and the University Medical Center Groningen in The Netherlands and hospitals throughout Germany.

RESULTS

No association with folic acid use was present (odds ratio = 1.1; 95% confidence interval: 0.8-1.4) for ARM as a group. Infant and maternal MTHFR C677T polymorphisms were weakly associated with isolated ARM in particular. Lack of folic acid supplement use in combination with infants or mothers carrying the MTHFR C677T polymorphism did not seem to increase the risk of ARM or subgroups of ARM. The relative excess risks due to interaction did not clearly indicate interaction on an additive scale either.

CONCLUSION

This first study investigating interactions between periconceptional folic acid supplement use and infant and maternal MTHFR C677T polymorphisms in the etiology of ARM did not provide evidence for a role of this gene-environment interaction.

Associations of anorectal malformations and related syndromes

Anorectal malformations (ARMs) represent a complex group of congenital anomalies resulting from abnormal development of the hindgut, allantois and Mullerian duct resulting in complete or partial urorectal septal malformations. There is a wide variety of phenotypic expression, ranging from mild anorectal to very complex severe ARM with >75 % having other associated malformations. 50 % of cases are syndromic although many may have other associated anomalies. This suggests a genetic link but the genetics of ARM are highly complex with a number of candidate genes being identified. Many can be classified as "field defects" as a result of a complex set of genetic interactions. Patients with associated malformations can be classified into those with multiple congenital anomalies (non-syndromic), those with chromosomal abnormalities and those with non-chromosomal syndromic associations, also, those with non-chromosomal syndromes and the influence of environmental factors (e.g. drugs in pregnancy). Although much is not known about the aetiology of ARM, the weight of evidence points to genetic factors as major causes for the condition. In this review, we look at the chromosomal and genetic associations and their underlying signalling pathways, to obtain a better understanding of the pathogenetic mechanisms involved in developing ARM. The spectrum of ARM phenotypic expression probably results from involvement and crosstalk between a number of critical signalling systems involved in development of this region. As a result, it may be expressed as a "field developmental defect" with many associated abnormalities. The role of environmental factors in the development of ARM is probably less.

CNV analysis in monozygotic twin pairs discordant for urorectal malformations

Early post-twinning mutational events can account for discordant phenotypes in monozygotic (MZ) twin pairs. Such mutational events may comprise genomic alterations of different sizes, ranging from single nucleotides to large copy-number variations (CNVs). Anorectal malformations (ARM) and the bladder exstrophy-epispadias complex (BEEC) represent the most severe end of the urorectal malformation spectrum. Recently, CNV studies in patients with sporadic ARM and the BEEC have identified de novo events that occur in specific chromosomal regions. We hypothesized that early arising, post-twinning CNVs might contribute to discordance in MZ twin pairs with ARM or the BEEC; knowledge of such CNVs might help to identify additional chromosomal regions involved in the development of these malformations. We investigated four discordant MZ twin pairs (three ARM and one BEEC) using molecular karyotyping arrays comprising 1,140,419 markers with a median marker spacing of 1.5 kb. Filtering the coding regions for possible disease-causing post-twinning de novo CNVs present only in the affected twin, but not in the unaffected twin or the parents, identified a total of 136 CNVs. These 136 CNVs were then filtered against publicly available databases and finally re-evaluated visually. No potentially causative CNV remained after applying these filter criteria. Our results suggest that post-twinning CNV events that affect coding regions of the genome did not contribute to the discordant phenotypes in MZ twin pairs that we investigated. Possible causes for the discordant phenotypes include changes in regulatory elements or smaller genetic changes within coding regions which may be detectable by whole-exome sequencing.

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.

Urological anomalies and chronic kidney disease in children with anorectal malformations

BACKGROUND

This study aims to predict risk factors for urological anomalies in children with anorectal malformations (ARM) and describes the clinical features of patients who have developed chronic kidney disease.

METHODS

We retrospectively reviewed infants with ARM who received surgery and were followed at the Sabah Women and Children's Hospital, Malaysia, from 1986 to 2010.

RESULTS

One hundred and twenty-two children with anorectal malformations were studied, after excluding 24 children with incomplete data. Three factors were significant as predictors of the presence of a urological anomaly: high ARM lesion (OR 3.12, 95%CI 1.1-8.9), the presence of genital abnormality (OR 2.95, 95%CI 1.10-7.91) and cloacal anomaly in girls (OR 8.27, 95% CI 1.91-35.6). The most common anomalies were vesicoureteric reflux, single kidney and neurogenic bladder. Chronic kidney disease (CKD) was noted in 5.7%, in children who had recurrent urinary tract infections, neurogenic bladder or complex renal tract pathology; end-stage renal failure was seen in only 0.8% of children with ARM.

CONCLUSION

Urological anomalies were seen in 23% of patients, but the overall incidence of CKD and end-stage renal disease is low. Early identification of infants with ARM at risk of renal failure may be important for renal survival.

Prenatal exposure to di-n-butyl phthalate induces anorectal malformations in male rat offspring

The objectives of this study were to investigate the dysplasia, histological malformations, and genetic abnormalities in male rats induced by maternal exposure to di-n-butyl phthalate (DBP). Here we report novel findings concerning developmental abnormalities resulting from prenatal exposure to DBP, which leads to significant anorectal malformations (ARMs) in male rat offspring. The incidence of ARMs was 39.5% in male offspring and all abnormal pups were complicated with secondary megacolon. General images, histological analysis and anatomy examination confirmed the malformation. The development abnormalities such as decreased bodyweight (BW) and anogenital distance (AGD), shortened body lengths (with tail removed), as well as increased abdominal circumference were observed at different developmental stages of ARMs in male rat. The developmental abnormalities in both solid organs (brain, heart, liver, spleen, lung and kidney) and reproductive organs (testes and epididymis) of abnormal pubs on PND35 were also investigated. In addition, the serum testosterone (T) level of ARMs in male rats on PND1 was significantly lower than that of controls with accompanying reduced expression of androgen receptor (AR), sonic hedgehog (Shh) and bone morphogenetic protein 4 (Bmp4) mRNA from tissues of the terminal rectum. These results conclusively demonstrate for the first time that in utero exposure to DBP leads to an increased likelihood for the development of ARMs and subsequent complicating megacolon in male rat offspring.

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.

Parental risk factors and anorectal malformations: systematic review and meta-analysis

BACKGROUND

Anorectal malformations (ARM) are rare forms of congenital uro-rectal anomalies with largely unknown causes. Besides genetic factors, prenatal exposures of the parents to nicotine, alcohol, caffeine, illicit drugs, occupational hazards, overweight/obesity and diabetes mellitus are suspected as environmental risk factors.

METHODS

Relevant studies published until August 2010 were identified through systematic search in PubMed, EMBASE, ISI Web of Knowledge and the Cochrane Library databases. Furthermore, related and cross-referencing publications were reviewed. Pooled odds ratios (95% confidence intervals) were determined to quantify associations of maternal and paternal smoking, maternal alcohol consumption, underweight (body mass index [BMI] < 18.5), overweight (BMI 25-29.9), obesity (BMI ≥30) and maternal diabetes mellitus with ARM using meta-analyses.

RESULTS

22 studies that reported on the association between prenatal environmental risk factors and infants born with ARM were included in this review. These were conducted in the United States of America (n = 12), Spain (n = 2), Sweden (n = 2), the Netherlands (n = 2), Japan (n = 1), France (n = 1), Germany (n = 1) and Hungary (n = 1). However, only few of these studies reported on the same risk factors. Studies were heterogeneous with respect to case numbers, control types and adjustment for covariates. Consistently increased risks were observed for paternal smoking and maternal overweight, obesity and diabetes, but not for maternal smoking and alcohol consumption. In meta-analyses, pooled odds ratios (95% confidence intervals) for paternal smoking, maternal overweight, obesity, pre-gestational and gestational diabetes were 1.53 (1.04-2.26), 1.25 (1.07-1.47), 1.64 (1.35-2.00), 4.51 (2.55-7.97) and 1.81 (1.23-2.65), respectively.

CONCLUSION

Evidence on risk factors for ARM from epidemiological studies is still very limited. Nevertheless, the few available studies indicate paternal smoking and maternal overweight, obesity and diabetes to be associated with increased risks. Further, ideally large-scale multicentre and register-based studies are needed to clarify the role of key risk factors for the development of ARM.

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.

Maternal and paternal risk factors for anorectal malformations: a Dutch case-control study

BACKGROUND

Anorectal malformations (ARM) are major congenital malformations that usually require a multitude of surgical procedures at a very early age and have a large impact on the lives of patients and their parents. The causes of ARM are still largely unknown, but they are assumed to have a multifactorial etiology. A few studies focused on environmental risk factors, but evidence is still scarce.

METHODS

In this Dutch case-control study (1996-2008), we investigated the role of maternal and paternal risk factors in the etiology of ARM. Parents of 85 ARM cases and 650 controls filled in a questionnaire. Controls were children treated with ear ventilation tubes.

RESULTS

A higher occurrence of fever during the first trimester of pregnancy was found for case mothers compared to control mothers (odds ratio [OR], 5.1; 95% Confidence Interval [CI], 0.9, 28.1). Maternal occupational exposure to industrial cleaning agents and solvents increased the risk of ARM three times (OR, 2.9; 95% CI, 0.9, 9.3). Overweight (Body Mass Index [BMI] > or = 25 kg/m(2)) before pregnancy also seemed to be associated with ARM (OR, 1.8; 95% CI, 1.1, 2.8), as well as maternal multivitamin use during pregnancy (OR, 1.6; 95% CI, 1.0, 2.7), paternal smoking (OR, 1.8; 95% CI, 1.1, 2.9), and paternal occupational exposure to exhaust fumes (OR, 1.9; 95% CI, 1.0, 3.6). Reported ARM in at least one first- or second-degree family member greatly increased the risk of having a child with an ARM (OR, 40.3; 95% CI, 4.8, 342.8).

CONCLUSIONS

This study revealed potential risk factors for ARM, including fever during pregnancy, maternal overweight, use of multivitamins, paternal smoking, and occupational exposures, but a familial component seems important as well.

Genetics of Hirschsprung disease and anorectal malformations

Hirschsprung disease (HD) and anorectal malformations (ARMs) result from alterations in hindgut development. It has long been recognized that both recur in families and thus result, at least in part, from genetic factors. Progress in the understanding of the genetic basis of HD has been made by the application of findings from genetic animal models of altered enteric nervous system development to human beings. Several genes have been shown to be important for human enteric nervous system development, and current work is progressing to identify genetic interactions that may explain the variable phenotype of HD. By contrast, understanding of the genetic factors underlying ARMs is much less developed. We and others have shown that genetic factors play an important role in the pathogenesis of ARMs, and many mouse genetic models suggest molecular pathways that may be altered in ARMs.

Long-term functional evaluation of fecal continence after laparoscopic-assisted pull-through for high anorectal malformations

BACKGROUND

The use of laparoscopy while performing an abdominal dissection for the mobilization of rectovesical fistula should have an impact on anorectal function, as compared to the original posterior sagittal anorectoplasty, where muscle complex was not cut and the rectum was pulled in a way similar to the old techniques for the abdominoperineal pull-through. This necessitates a functional reevaluation.

MATERIALS AND METHODS

A prospective case study included 15 patients treated with a laparoscopic-assisted pull-through for high anorectal malformation. Laparoscopy was used for abdominal dissection and ligation of the fistula, with the pull-through completed by a small perineal incision centered over the external sphincter. Nine of them are now older than 3 years for fecal continence evaluation. After the approval of the Ethical Committee for Medical Research in the Department of Surgery at Ain Sams University (Cairo, Egypt) and obtaining an informed consent from the parents, they were subjected to a full clinical history and a checklist about motions and soiling to be filled in over 1 month, a barium enema to check for any dilatation, anorectal manometry to evaluate resting pressure, maximum squeezing pressure, and sphincter relaxation, and MRI (magnetic resonance imaging) to evaluate the central situation of the rectum within the sphincter and the degree of development of the sphincter. Their degree of continence was graded according to the Kelly score.

RESULTS

Six of 9 patients are clean without any attacks of fecal soiling or incontinence, and they evacuate spontaneously but need the application of a rectal suppository for evacuation from time to time. The remaining 3 patients had variable degrees of fecal incontinence. One of them had mucosal prolapse and was excised with good cleanliness postoperatively. The remaining 2 patients are managed by medical control and they are clean with minimal soiling when stools are loose. MRI and barium enema showed a centrally placed rectum in the muscle complex without dilatation in all cases. Manometry showed a high resting pressure that decreased on straining in the 7 clean patients and low in 2. The resting pressure did not increase on squeezing and all showed weak rectoanal inhibitory reflex (RAIR). One patient developed dysurea and constipation 1 year after surgery, as diagnosed by VCUG (voiding cystourethrogram) to have a diverticulum at the site of excised fistula causing rectal and urethral obstruction treated by a transabdominal excision with a good functional result.

CONCLUSION

The state of continence with the laparoscopic technique in high anorectal malformations in this study showed acceptable results but needs bigger series with longer follow-up for a proper evaluation of this technique.