Associated malformations in patients with anorectal anomalies

Genome-wide copy number variation study in anorectal malformations

Anorectal malformations (ARMs, congenital obstruction of the anal opening) are among the most common birth defects requiring surgical treatment (2-5/10 000 live-births) and carry significant chronic morbidity. ARMs present either as isolated or as part of the phenotypic spectrum of some chromosomal abnormalities or monogenic syndromes. The etiology is unknown. To assess the genetic contribution to ARMs, we investigated single-nucleotide polymorphisms and copy number variations (CNVs) at genome-wide scale. A total of 363 Han Chinese sporadic ARM patients and 4006 Han Chinese controls were included. Overall, we detected a 1.3-fold significant excess of rare CNVs in patients. Stratification of patients by presence/absence of other congenital anomalies showed that while syndromic ARM patients carried significantly longer rare duplications than controls (P = 0.049), non-syndromic patients were enriched with both rare deletions and duplications when compared with controls (P = 0.00031). Twelve chromosomal aberrations and 114 rare CNVs were observed in patients but not in 868 controls nor 11 943 healthy individuals from the Database of Genomic Variants. Importantly, these aberrations were observed in isolated ARM patients. Gene-based analysis revealed 79 genes interfered by CNVs in patients only. In particular, we identified a de novo DKK4 duplication. DKK4 is a member of the WNT signaling pathway which is involved in the development of the anorectal region. In mice, Wnt disruption results in ARMs. Our data suggest a role for rare CNVs not only in syndromic but also in isolated ARM patients and provide a list of plausible candidate genes for the disorder.

In vivo knockdown of Brachyury results in skeletal defects and urorectal malformations resembling caudal regression syndrome

The T-box transcription factor BRACHYURY (T) is a key regulator of mesoderm formation during early development. Complete loss of T has been shown to lead to embryonic lethality around E10.0. Here we characterize an inducible miRNA-based in vivo knockdown mouse model of T, termed KD3-T, which exhibits a hypomorphic phenotype. KD3-T embryos display axial skeletal defects caused by apoptosis of paraxial mesoderm, which is accompanied by urorectal malformations resembling the murine uro-recto-caudal syndrome and human caudal regression syndrome phenotypes. We show that there is a reduction of T in the notochord of KD3-T embryos which results in impaired notochord differentiation and its subsequent loss, whereas levels of T in the tailbud are sufficient for axis extension and patterning. Furthermore, the notochord in KD3-T embryos adopts a neural character and loses its ability to act as a signaling center. Since KD3-T animals survive until birth, they are useful for examining later roles for T in the development of urorectal tissues.

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.

Anorectal malformations

This article reviews the current status of anorectal malformations in the neonate. It begins by discussing the history, epidemiology, and embryology, followed by a discussion of the genetic process causing these diseases. Diagnosis and workup is then discussed, followed by specific details of the surgical treatment of these malformations. The article concludes with a brief review of the complications and long-term outcomes in these children.

Evaluation of the perianal muscular complex in the prenatal diagnosis of anorectal atresia in a high-risk population

OBJECTIVES

To investigate whether sonographic identification of the fetal perianal muscular complex (PAMC) is of value in the prenatal detection of anorectal atresia in a high-risk population.

METHODS

During an 8-year study period, a total of 189 pregnancies at high risk for fetal anorectal atresia were prospectively examined for the presence/absence of the PAMC on axial ultrasound views of the fetal perineum. The prenatal findings were confirmed postnatally or at the time of postmortem examination.

RESULTS

The median gestational age at examination was 27 (range, 15-37) weeks. The PAMC was identified in 175 fetuses, all of which had a normal anorectal canal at the time of delivery or at postmortem examination. The PAMC was not identified prenatally in the 14 remaining cases, and the anus was absent in 11 fetuses with anorectal atresia and in two with urorectal septum malformation sequence. There was one false-positive case, in which the anus was anatomically and functionally normal but ectopically located, opening into the vaginal vestibule. Among these 14 cases of anorectal malformation, prenatal dilatation of the distal bowel was seen in nine (64.3%) and intraluminal calcified meconium or enterolithiasis in five (35.7%). Overall, absent PAMC on prenatal sonography in this high-risk population had a sensitivity of 100%, specificity of 99%, true-positive rate of 93% and false-positive rate of 7% for the diagnosis of anorectal atresia.

CONCLUSIONS

In a high-risk population, the absence of PAMC seems to be a highly sensitive and specific sonographic marker for anorectal atresia. The role of routine sonographic identification of the PAMC at the second-trimester scan to screen for cases of isolated anal atresia remains to be determined.

Children with high and intermediate imperforate anus: their experiences of hospital care

PURPOSE

The purpose of this study was to examine the experiences of children with high and intermediate imperforate anus (IA), and specifically their experiences of hospital care.

METHODS

Twenty-five children born with high and intermediate IA participated; 9 boys and 16 girls. The mean age was 10.5 years (range 8.0-13.6). Two control groups were involved in the study. A self-report questionnaire was used to gather the data concerning children's experiences of hospital care. Items were scored on a 5-point Likert scale.

RESULTS

The children's responses on hospital care items scored high. The children with IA reported being less satisfied with the information given, and understood less why they needed to visit the hospital than did the children in the two control groups.

CONCLUSION

The children's experiences of care seemed to be positive even though the children born with IA are subjected to invasive treatment. More research is called for in the unexplored area of information to the children, and particularly to the children born with a defect. Children's views are important and should always be considered, as their answers most certainly reflect a genuine experience, contributing to the further development of their specific care.

Urological anomalies in anorectal malformations in The Netherlands: effects of screening all patients on long-term outcome

INTRODUCTION

Urological anomalies are frequently seen in patients with anorectal malformations (ARM) and can result in upper urinary tract deterioration. Whether the current method of screening is valid, adequate and needed for all patients is not clear. We, therefore, evaluated the urological screening methods in our ARM patients for changes in urological treatment, outcome and follow-up.

METHODS

The medical records of 331 children born with an ARM in the period 1983-2003 were retrospectively studied. Documentation of diagnosis, screening method, urological anomalies, treatment, complications, follow-up and outcome were measured.

RESULTS

The overall incidence of urological anomalies was 52%. The incidence of urological anomalies and urological follow-up time decreased with diminishing complexity of the ARM. Hydronephrosis, vesico-urethral reflux, lower urinary tract dysfunction and urinary incontinence were encountered most. Treatment invasiveness increased with the increase of complexity of an ARM. Lower urinary tract dysfunction needing urological care occurred in 43% in combination with lumbosacral or spinal cord anomalies and in 8% with no abnormalities in the lumbosacral-/spinal region.

CONCLUSIONS

Urological anomalies in patients with complex ARM are more severe than in patients with less complex ARM. Ultrasonography of the urinary tract should be performed in all patients. Voiding cysto-urethrography can be reserved for patients with dilated upper urinary tracts, urinary tract infections or lumbosacral and spinal abnormalities. All patients with complex ARM need urodynamic investigations. When using these indications, the screening for urological anomalies in ARM patients can be optimized with long-term follow-up in selected patients.

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.

Analysis of genitourinary anomalies in patients with VACTERL (Vertebral anomalies, Anal atresia, Cardiac malformations, Tracheo-Esophageal fistula, Renal anomalies, Limb abnormalities) association

The goal of this study was to describe a novel pattern of genitourinary (GU) anomalies in VACTERL association,which involves congenital anomalies affecting the vertebrae,anus, heart, trachea and esophagus, kidneys, and limbs.We collected clinical data on 105 patients diagnosed with VACTERL association and analyzed a subset of 89 patients who met more stringent inclusion criteria. Twenty-one percent of patients have GU anomalies, which are more severe (but not more frequent) in females. Anomalies were noted in patients without malformations affecting the renal, lower vertebral, or lower gastrointestinal systems. There should be a high index of suspicion for the presence of GU anomalies even in patients who do not have spatially similar malformations.

VACTERL-H syndrome: first trimester diagnosis

We present two consecutive female fetuses with identical upper limb anomalies. The first of the cases was found to have ventriculomegaly, atrial septal defect, anal atresia, narrowing of the duodenal lumen and unilateral renal agenesis at the end of the second trimester. These abnormalities were characteristic of autosomal recessive VACTERL-H syndrome. The second case was diagnosed to have absent radii and thumbs at 11 weeks. Detailed examination of fetal limbs in the first trimester screening in cases with high risk is useful for early detection of this malformation.

Two cases of 22q11.2 deletion syndrome with anorectal anomalies and growth retardation

Clinical features associated with the deletion of 22q11.2 are highly variable. Most are diagnosed by cardinal congenital heart disease or hypoparathyroidism. In cases without major features, an early accurate diagnosis of 22q11.2 deletion syndrome is difficult. Congenital anorectal malformations (ARM), which can be detected soon after birth, have been rarely reported in 22q11.2 deletion syndrome. We report two cases of 22q11.2 deletion syndrome with ARM who showed growth retardation. ARM was detected in both patients without congenital heart disease or hypoparathyroidism at early infancy and they were followed by pediatric surgeons. Later, failure to thrive or short stature became evident, and they consulted with pediatric endocrinologists who subsequently confirmed the diagnosis of 22q11.2 deletion by fluorescent in situ hybridization analysis. The combination of ARM and growth retardation may lead to an early diagnosis of 22q11.2 deletion syndrome.

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.

Congenital gastrointestinal anomalies in anorectal malformations: what relationship and management?

To date, no systematic review of gastrointestinal anomalies associated with anorectal malformations has been performed. We report the management of three challenging cases of neonates affected by congenital gastrointestinal and anorectal malformations and we review the pertinent published reports to disclose the incidence and outcome of this combination. In 3951 anorectal malformations, the incidence of digestive tract anomalies was approximately 15%. The association of multiple congenital gastrointestinal defects strongly increased the case complexity and worsened the outcome. Based on our study, the application of a rational and staged management plan provides easier diagnosis and treatment of complex cases. Moreover, keeping in mind the likely co-occurrence of anorectal and gastrointestinal anomalies could help avoid misdiagnosis and prevent life-threatening complications. Finally, the knowledge of this association and its successful management can help the multi-specialist team to become more confident in counselling, diagnosis and treatment.

Genetic testing in other GI diseases

Gastrointestinal development is a complex process comprising folding of the endodermal layer to form the primitive gut tube, cell differentiation along its anteroposterior axis, the budding of the various organ primordia and development of derivative organs like the liver and pancreas and the colonisation of the gut with neuronal precursors. Genetic factors are increasingly recognised as playing a significant role in the disturbance of this developmental process which underlies congenital malformations and gastrointestinal disorders. Furthermore, genetic variation and its interaction with environmental influences play an important role in the pathogenesis of functional gastrointestinal disorders. In this review, we discuss the contribution of genetic variants, ranging from highly penetrant mutations and chromosomal abnormalities to genetic polymorphisms, to the pathogenesis of a number of structural and functional gastrointestinal disorders.

Investigation of FGF10 as a candidate gene in patients with anorectal malformations and exstrophy of the cloaca

The spectrum of anorectal malformations (ARM) comprises anal stenosis, ectopic anus, recto-urogenital fistula, persistent cloaca, multisystem VACTERL (VATER associations including cardiac and limb anomalies) associations, and exstrophy of the cloaca (CE). The latter also constitutes the most severe form of the bladder exstrophy epispadias complex. Since recent data revealed that fibroblast growth factor 10 (fgf-10) invalidation in mice resulted in a genetically reproducible urorectal defect, we considered FGF10 a suitable candidate gene for ARM and CE, as the protein seems to be involved in the development of this primary developmental field. A total of 20 patients (ten with ARM and VACTERL association, respectively, and ten with CE) were analysed for genomic mutations in the coding regions and exon-intron boundaries of FGF10. Aside from a common FGF10 variant no deviation from the wild-type sequence could be detected and data obtained is not supportive of FGF10 as a genetic cause of ARMs or CE in the patients investigated. Nonetheless, mutations in possibly further upstream located promoter regions and/or unknown regulatory sequences or non-coding regions cannot be excluded. Furthermore, it cannot be ruled out that other genes involved in the signalling pathway of FGF10 may contribute to the formation of these congenital malformations.