Skip to main content
NCBI home page
UKPMC Funders Author Manuscripts logoLink to UKPMC Funders Author Manuscripts
. Author manuscript; available in PMC: 2024 Apr 24.
Published in final edited form as: Am J Med Genet A. 2022 Dec 7;191(3):730–741. doi: 10.1002/ajmg.a.63067

Clinically diverse and perinatally lethal syndromes with urorectal septum malformation sequence

Shalini S Nayak 1, Robert Harkness 2,3, Anju Shukla 1, Siddharth Banka 2,3, William G Newman 2,3, Katta M Girisha 1,4,✉
PMCID: PMC7615864  EMSID: EMS195514  PMID: 36478354

Abstract

Urorectal septum malformation sequence (URSMS) is characterized by a spectrum of anomalies of the urogenital system, hindgut and perineum. It is presumed to be a constellation of an embryonic defect. Herein, we analyzed the clinically diverse syndromes associated with URSMS in our perinatal evaluation unit. We reviewed fetuses with URSMS in referrals for perinatal autopsy over a period of 3 years. Chromosomal microarray and genome sequencing were performed whenever feasible. Literature was reviewed for syndromes or malformations with URSMS. We ascertained URSMS in 12 of the 215 (5%) fetuses. Nine fetuses (75%) had complete URSMS and remainder had partial/intermediate URSMS. Eleven fetuses had malformations of other systems that included: cerebral ventriculomegaly; right aortic arch with double outlet right ventricle; microcephaly with fetal akinesia deformation sequence; ventricular septal defect and radial ray anomaly; thoraco-abdominoschisis and limb defects; myelomeningocele; spina bifida and fused iliac bones; omphalocele; occipital encephalocele; lower limb amelia and cleft foot. We report on six fetuses with recurrent and five fetuses with unique malformations/patterns where URSMS is a component. Exome sequencing (one family) and genome sequencing (eight families) were performed and were nondiagnostic. Additionally, we review the literature for genetic basis of this condition. URMS is a clinically heterogeneous condition and is a component of several multiple malformation syndromes. We describe several unique and recurrent malformations associated with URSMS.

Keywords: ambiguous genitalia, imperforate anus, persistent cloaca, urorectal septum malformation sequence

1. Introduction

Urorectal septum malformation sequence (URSMS) refers to a spectrum of anomalies involving urogenital system, hindgut and perineum. It is hypothesized that URSMS results from deficiency of the caudal end of the mesoderm or defect in the cloacal endoderm, peri-cloacal mesenchyme, and genital ectoderm arising during early embryogenesis (Jain et al., 2008). However, a definitive cause is not yet identified. This sequence is described as complete, partial, intermediate, and urogenital sinus anomaly based on the persistent cloaca and perineal openings (Huang et al., 2016; Wheeler & Weaver, 2001).

Often, other malformations are also observed with URSMS (Tennant et al., 2014). Recurrence in families (vertical and horizontal), though extremely rare, has also been reported (Aggarwal & Phadke, 2013; Mills & Pergament, 1997) suggesting the existence of yet undetermined monogenic etiology. Hsu et al. provided the first evidence by identifying de novo variants in Caudal Type Homeo Box Transcription Factor 2 (CDX2) in patients with persistent cloaca (Hsu et al., 2018). Herein, we describe 12 fetuses with syndromic and non-syndromic URSMS depicting the clinically diverse perinatal lethal malformations.

2. Subjects and Methods

We reviewed fetuses with URSMS in referrals for perinatal autopsy over a period of 3 years at our perinatal genetics services clinic. The study has the approval of the institutional ethics committee and informed consents were taken from the families. Perinatal evaluation was performed (Khong & Malcomson, 2015; Nayak et al., 2015) in all the fetuses. Family history of the couple, antenatal details, exposure to teratogens, consanguinity, three-generation pedigree, findings on antenatal ultrasonography and fetal echocardiography, results of laboratory tests, mode of delivery, and gestational age were systematically documented. Fetal weight, total length, foot length, head circumference, chest circumference, and other measurements were taken and compared with available standard growth charts (Khong & Malcomson, 2015). Anteroposterior and lateral views of the fetus were radiographed to rule out skeletal abnormalities. Additionally, magnetic resonance imaging of the fetal brain/whole body was performed whenever possible. We collected appropriate samples such as skin biopsy, liver, muscle, bone marrow, or umbilical cord from the fetuses. They were used to obtain DNA/RNA/cell lines. An external examination was done from head to toe to document dysmorphism/anomalies. Dissection of the whole body was performed using standard perinatal autopsy procedures (Khong & Malcomson, 2015; Osborn & Lowe, 2017). All internal organs/structures were examined carefully. The normal anatomy and anomalies observed were documented with photographs. Careful examination of placenta was carried out to rule out the cause of fetal demise. Histopathological examination of fetal tissues/organs was performed as appropriate.

Chromosomal microarray, karyotype, exome sequencing, and genome sequencing were performed using fetal genomic DNA whenever possible. For whole genome sequencing (WGS), DNA library preparation and sequencing was performed using DNBSeq platform at Beijing Genomics Institute (BGI), China with standard 30× sequencing depth. Reads were aligned to hg19 human reference genome via Burrows–Wheeler Aligner (BWA v.0.6.2). Variants were called using Genome Analysis Toolkit (GATK) 4.0. Annotation was performed using VarSeqTM v2.2 (Golden Helix Inc., Boseman, MT, USA). Rare variants (<0.01%) were identified from population frequencies observed in the Genome Aggregation Database (gnomAD) and using population frequencies from in-house exome sequencing. In silico variant predictions were modeled using Polyphen-2 (http://genetics.bwh.harvard.edu/pph2/), Mutation taster (http://www.mutationtaster.org/), Mutation Assessor (http://mutationassessor.org/r3/), SIFT (Sorting Intolerant From Tolerant) (http://sift.bii.a-star.edu.sg/), CADD (GRCh37-v1.4), and REVEL (Ioannidis et al., 2016). Rare intronic and splice site variants were assessed using SpliceAI (Jaganathan et al., 2019). Fetal sex was inferred by non-pseudoautosomal region X-chromosome genotype analysis using the bcftools guess-ploidy plugin, allowing for genotyping error rate of 0.1.

A careful delineation of the URSMS subtypes and anomalies in other systems was carried out. Literature was reviewed for syndromes or the phenotypes associated with URSMS. We searched PubMed, Online Mendelian Inheritance in Man and other databases with the phrases “urorectal septum malformation sequence,” “persistent cloaca,” “cloacal dysgenesis,” and “cloaca” to look for the associated malformations.

3. Results

We observed URSMS in 12 fetuses (5%) in our cohort of 215 fetal losses. The gestational age ranged 13–36 weeks. Ambiguous genitalia with no perineal openings and persistent cloaca characterizing the complete URSMS was observed in nine (9/12, 75%) fetuses. There was persistent cloaca with a single perineal opening (partial URSMS) in two fetuses and the other fetus had intermediate type (complete partition of the persistent cloaca without perineal openings) of URSMS. Oligohydramnios (4/12, 33%) or renal agenesis/anomaly (4/12, 33%) or megacystis (1/12, 8%) were observed prenatally in the cohort. The clinical details of all the fetuses are provided in Table 1. Overall, we could identify sex in five fetuses based on external and internal examination and histopathology. Recurrence of the condition was not observed in any of the families in our cohort.

Table 1. Clinical features in fetuses with urorectal septum malformation sequence (URSMS).

Features Fetus 1 Fetus 2 Fetus 3 Fetus 4 Fetus 5 Fetus 6 Fetus 7 Fetus 8 Fetus 9 Fetus 10 Fetus 11 Fetus 12
Gestational age in weeks 13 18 18 24 20 14 36 Not available 14 30 21 12
Gender Female Unknown Male Female Female Unknown Unknown Unknown Unknown Unknown Male Unknown
Consanguinity No No No No No No No Not available No No No No
Gravida Primi Second Third Primi Second Second Second Not available Primi Second Primi Primi
Antenatal events Fever in first trimester Nil Diabetes mellitus and hypothyroidism Nil Nil Nil Nil Not available Twin pregnancy Nil Nil Hypothyroidism and polycystic ovarian disease
Type of URSMS Complete Complete Intermediate Partial Complete Complete Complete Complete Complete Complete Partial Complete
External genitalia Small phallus-like structure with no urogenital openings Small phallus-like structure with no urogenital openings Small phallus-like structure with scrotum with no urethral opening Ambiguous genitalia with no urogenital openings Small phallus-like structure with no urogenital openings Small phallus-like structure with no urogenital openings Small phallus-like structure with no urogenital openings Small phallus-like structure with no urogenital openings Small phallus-like structure with no urogenital openings Ambiguous genitalia with no urogenital openings Phallus-like structure with a perineal opening Small phallus-like structure with no urogenital openings
Anal opening Absent Absent Absent Present Absent Absent Absent Absent Absent Absent Absent Absent
Persistent cloaca Present (blind ending) Present (blind ending) Urinary bladder with urethral opening Vesico-vaginal fistula with common opening Present (blind ending) Present (blind ending) Present (blind ending) Present (blind ending) Present (blind ending) Present (blind ending) Recto-vesicle fistula with common perineal opening Present (blind ending)
Internal genitalia Ovaries, fallopian tube Indifferent gonads Testes Ovaries and uterus ? Ovaries, no uterus Indifferent gonads Gonads were not found Indifferent gonads Indifferent gonads Indifferent gonads Testes Indifferent gonads
Hindgut Draining into cloaca Draining into cloaca Blind ending Atresia Draining into cloaca Draining into cloaca Draining into cloaca Draining into cloaca Draining into cloaca Draining into cloaca Draining through common perineal opening Draining into cloaca
Renal agenesis (unilateral/ bilateral) No No No No Left renal agenesis Left renal agenesis (with adrenal) Bilateral renal agenesis Left renal agenesis No Bilateral renal agenesis Bilateral renal agenesis Right renal agenesis
Cystic kidneys Present (horseshoe) Present (fused) Hypoplastic Absent Absent Absent Absent Absent Absent Absent Absent Absent
Umbilical cord Three vessel Two vessel Two vessel Three vessel Two vessel Not available Three vessel Three vessel Three vessel Two vessel Three vessel Three vessel
Sacrum Absent ossification Absent ossification Reduced ossification Normal Normal Absent ossification Absent ossification Absent ossification Absent ossification Absent ossification Normal Absent ossification
Central nervous system anomalies Absent Dilated lateral cerebral ventricles Absent Small brain Absent Absent Lipomeningomyelocele Lumbar spina bifida Absent Occipital encephalocele Absent Absent
Cardiac anomalies Absent Absent Right aortic arch, double outlet right ventricle with ventricular septal defect Absent Membranous ventricular septal defect Dextrocardia Absent Absent Absent Absent Absent Absent
Limb anomalies Absent Proximally placed left thumb, contractures across elbows, hips and knees, talipes equinovalgus of right foot Absent Bilateral congenital talipes equinovarus Bilateral radial deviation of hands, bowed fore arms, rudimentary right thumb with absent radius, absent F1 and F2 on left hand with hypoplastic radius Short right lower limb with contractures, reduction defect of left lower limb below the knee with bowed femora Right radial club hand, bilateral clubfeet and rhizomelia of left lower limb Absent Unilateral club foot Absent Proximally placed right thumb, complete absence of left lower limb Short right lower limb with joint contractures across hip, knee and ankle, right cleft foot with absent two central digits (split foot)
Skeletal abnormalities Absent Absent Absent Scoliosis, crowding of ribs and hyper mineralization cranium Absent Kyphoscoliosis at thoracolumbar region Lumbar scoliosis, segmentation defect of thoracic and lumbar vertebrae Fused iliac bones, absence of ossification centers for lower lumbar vertebrae Scoliosis at lumbar region Segmentation defect in lower lumbar vertebrae Absent Kyphoscoliosis at thoracolumbar region
Ventral body wall defect Absent Absent Absent Absent Absent Lower thoracic and abdominal wall defect with the herniation Absent Absent Omphalocele Absent Absent Anterior abdominal wall defect with the herniation
Other anomalies Protuberant abdomen with thin and transparent abdominal wall Rudimentary allantois Nonlobulated lungs Microcephaly, excessive skin on the occipital and neck region, sloping forehead, dysmorphic ears, hypertelorism, midface protrusion, macrostomia, micro-retrognathia, short neck, pterygia, camptodactyly, overriding fingers, craniosynostosis, ankyloglossia, hypoplastic lungs Facial asymmetry on right side, hypertelorism, short nose, ante verted nares, long philtrum and retrognathia Absent Pulmonary hypoplasia Absent Absent Frontal sloping, flattened nasal tip, micrognathia, dysmorphic ears, short neck, bilateral pulmonary hypoplasia Hypertelorism, retrognathia, persistent vitellointestinal duct Absent
Fetal karyotype Not done Not done Done (Normal) 46, XX Not done Not done Not done Not done Not done Not done Not done Not done
Chromosomal microarray Not done Not done Not done Normal Not done Not done Not done Not done Not done Not done Not done Not done
Genome sequencing Singleton Trio Singleton Trio (Also underwent singleton exome) Singleton Trio Not done Singleton Singleton Not done Not done Not done
Inferred genomic sex Female Male Male Female Female Male Not done Male Female Not done Not done Not done
Open in a new tab

Eleven (11/12, 91.6%) fetuses had malformations (Table 1) outside the urinary tract, internal and external genital and hindgut. Anomalies of vertebrae (10/12, 83%), limbs (8/12, 66%), central nervous system (5/12, 41%), umbilical cord (4/11, 36%), heart (3/12, 25%), and ventral body wall (3/12, 25%) were frequently noted in our cohort.

3.1. Unique malformations with URSMS

After reviewing the literature for syndromes or conditions with multiple malformations where URSMS is a component, we note, five fetuses had a rare or unique pattern of multiple malformations in our cohort. These rare presentations are described here.

3.1.1. Complete URSMS with cerebral ventriculomegaly (Fetus 2)

The fetus was ascertained at 18 weeks of gestation in view of oligohydramnios and bilateral renal agenesis. The fetus had normal anthropometric measurements (weighed 175 g, measured 22 cm in length with head circumference of 15 cm). Depressed nasal bridge, micro-retrognathia, proximally placed left thumb, contractures across elbows, hips and knees, calcaniovalgus of right foot and two vessels umbilical cord were seen. Ambiguous external genitalia with a small phallus like structure and absence of perineal openings was noted. Dilated lateral cerebral ventricles were evident on gross examination and magnetic resonance imaging of fetal brain (Figure 1). Kidneys were multicystic and fused, with narrow ureters draining into blindending cloaca. Rudimentary allantois and indifferent gonads were observed. Radiographs of the fetus showed the absence of ossification of sacral vertebrae.

Figure 1.

Figure 1

Open in a new tab

Depressed nasal bridge, micro-retrognathia, contractures in upper and lower limbs (a), proximally placed left thumb (b), ambiguous external genitalia with absent perineal openings (c) and multicystic and fused kidneys with narrow ureters and hindgut (black asterisk, d) draining into common, blind cloaca (arrow, d) were observed in Fetus 2. Imaging revealed cerebral ventriculomegaly (white asterisk, e) and absence of ossification of sacral vertebrae (f).

3.1.2. Intermediate URSMS, right aortic arch with double outlet right ventricle (Fetus 3)

A third gravida with diabetes mellitus and hypothyroidism was noted to have anhydramnios, symmetric early onset of growth retardation and cardiac defect in the fetus antenatally. Evaluation of fetus showed normal anthropometry (corresponding to 18 weeks of gestation) with short nose, long philtrum, retrognathia, imperforate anus, small phallus with small scrotum, and single umbilical artery. Right aortic arch with double outlet right ventricle, sub-aortic ventricular septal defect, hypoplastic left ventricle, and nonlobulated lungs were evident (Figure 2). Both kidneys were hypoplastic and ureters draining into the urinary bladder. The urethral opening was absent and gonads appeared to be testes. There was absence of ossification centers for sacrum.

Figure 2.

Figure 2

Open in a new tab

Fetus 3 had short nose, long philtrum, retrognathia (a), small phallus with scrotum and imperforate anus (b), right aortic arch (black asterisk, c), hypoplastic kidneys, separate rectum (arrow) and urinary bladder (white asterisk) with no perineal openings (d) and poorly ossified sacral vertebrae (e).

3.1.3. Partial URSMS, microcephaly, and fetal akinesia deformation sequence (Fetus 4)

The fetus weighed 256 g (–3.1 SD) measured 17 cm (–6.8 SD) in length with head circumference of 15 cm (–4.5 SD) at 24 weeks of gestation. Trigonocephaly was noted with fused anterior fontanel and excessive skin on the occipital and neck region, sloping forehead, dysmorphic ears, hypertelorism, midface protrusion, wide mouth, and micro-retrognathia. The fetus also had short neck with webbing, pterygia across the axillae, elbows, hips and knees, camptodactyly, over-riding of fingers, bilateral congenital talipes equinovarus, ambiguous external genitalia with common urogenital opening and atresia of anal canal (Figure 3).

Figure 3.

Figure 3

Open in a new tab

Microcephaly, sloping forehead, dysmorphic ears, hypertelorism, midface protrusion, macrostomia and micro-retrognathia, short neck with webbing, pterygia across axillae, elbows, hips and knee joints, ambiguous external genitalia (a, b), ankyloglossia (white arrow), hypoplastic lungs (black arrow, c), premature closure of fontanelle (asterisk, d), small brain (e) and scoliosis, crowding of ribs and hyper-mineralized cranium (f) were evident in Fetus 4.

Further examination disclosed underdeveloped brain, ankyloglossia, severely hypoplastic lungs, absence of muscle mass in upper and lower limbs, atresia of terminal portion of hindgut, presence of ovaries and uterus, vesicovaginal fistula with common perineal opening. Scoliosis, crowding of ribs, hyper mineralized cranium, and small head were noted on radiography. Fetal karyotype and chromosomal microarray were normal. Exome sequencing from fetal DNA was nondiagnostic.

3.1.4. Partial URSMS with amelia (Fetus 11)

Prenatal diagnosis disclosed bilateral renal agenesis with absent urinary bladder, malformed left lower limb and intrauterine growth retardation in a fetus. The fetus weighed 223 g (–0.3 SD) measured 19 cm (–2 SD) in length at 19 weeks of gestation. Hypertelorism, retrognathia, proximally placed right thumb, and complete absence of left lower limb were evident. There was a phallus-like structure with a single perineal opening. Persistent vitellointestinal duct (Meckel's diverticulum), bilateral renal agenesis, and absent ureters with rudimentary urinary bladder were noted in the fetus (Figure 4). The rectum was communicating with the lower part of bladder and was drained by a common perineal opening. Gonads were confirmed to be testes on histopathology.

Figure 4.

Figure 4

Open in a new tab

There was amelia of left lower limb (a), phallus-like structure with single perineal opening (white arrow, b), Meckel’s diverticulum (black arrow, c), bilateral renal agenesis (white asterisk, d), incomplete separation of rectum, and rudimentary bladder with common outlet (black asterisk, e) in Fetus 11.

3.1.5. URSMS, abdominal wall defect, limb contractures with cleft foot (Fetus 12)

A primigravida with history of laminectomy for scoliosis, polycystic ovarian disease and hypothyroidism underwent pregnancy interruption at 12 weeks of gestation. Anterior abdominal wall defect with herniation of liver, cystic area in lower portion of abdomen, and posterior bending of lower limbs were observed on ultrasonography.

Growth parameters of the fetus were within normal limits. There was an anterior abdominal wall defect with herniation of liver, stomach, spleen, pancreas, and loops of small and large intestine partially covered by peritoneum. Severe kyphoscoliosis at the thoracolumbar region, short right lower limb with joint contractures across hip, knee, and ankle were noted (Figure 5). Right cleft foot was observed with absence of two central digits. Imperforate anus, ambiguous external genitalia, indifferent gonads, a defect in diaphragm, agenesis of right kidney and right adrenal gland, persistent cloaca with hindgut and left ureter draining into it, and atresia of cloacal opening were additional findings.

Figure 5.

Figure 5

Open in a new tab

Images depict anterior abdominal wall defect with herniation of abdominal viscera, kyphoscoliosis (a), contractures and spilt right foot (white arrow, b) and ambiguous external genitalia with absent perineal openings (black arrow, c) in Fetus 12.

3.2. Recurrent malformations with URSMS

We observed several recurrent malformations that are already known to occur with URSMS in six fetuses of our cohort. They include radial ray defect, unilateral renal agenesis, and ventricular septal defect suggestive of vertebral defects, anal atresia, tracheoesophageal fistula with esophageal atresia and radial or renal dysplasia (VATER) (Fetus 5); thoraco-abdominoschisis and limb defects (Fetus 6); myelomeningocele/occipital encephalocele, renal agenesis with vertebral segmentation defect (Fetuses 7 and 10); spina bifida and fused iliac bones (Fetus 8) and omphalocele and scoliosis (Fetus 9). The antenatal history, pedigree, clinical findings, and images of the fetuses with recurrent phenotypes are provided in supplementary information S1.

3.3. Genomic testing

Genomic testing was performed in eight (8/12) families. Fetal karyotype was available for Fetus 3 and Fetus 4 following prenatal invasive testing and showed normal chromosomes. In Fetus 4, chromosomal microarray did not reveal any clinically significant copy number variations. Singleton exome sequencing (nondiagnostic) was carried in Fetus 4. Fetuses 1, 3, 5, 8, and 9 underwent singleton genome sequencing, whereas Fetuses 2, 4, and 6 underwent trio-genome sequencing. Genetic analysis inferred Fetuses 1, 4, 5, and 9 were female, and Fetuses 2, 3, 6, and 8 were male. Data analysis did not identify any pathogenic single nucleotide variants in known genes associated with the URSMS phenotype, but variants of interest have been identified in Fetuses 1, 3, 8, and 9 (Table 2).

Table 2. Variants of interest identified from WGS of eight fetuses with URSMS.

Fetus Gene Zygosity GRCh37 coordinate cDNA Protein GnormAD missense z-score (observed/expected) GnormAD AF GnormAD south Asian AF Align GVGD Mutation taster Polyphen2 SIFT CADD REVEL ACMG classification ACMG evidence
1 TMEM132A Het 11:60701998A > G NM_017870.2: c.1601A > G p.Glu534Gly 0.8 (590/647) 0 0 C0 Benign Possibly Damaging (0.787) Tolerated (0.27) 23.6 0.13 Uncertain Significance PM2, PB4
3 NALCN Het 13:101712309 T > A NM_052867.4: c.4766A > T p.Gln1589Leu 4.96 (563/1005.1) 0 0 C0 Deleterious Possibly Damaging (0.93) Deleterious (0.01) 23.3 0.864 Uncertain Significance PM2, PP2, PP3
8 HOXD9 Het 2:176987773A > G NM_014213.4: c.277A > G p.Ser93Gly 0.58 (147/168) 0 0 C0 Benign Possibly Damaging (0.789) Tolerated (0.10) 22.9 0.383 Uncertain Significance PM1, PM2, BP4
8 SLIT2 Het 4:20620441G > A NM_004787.4: c.4399G > A p.Gly1467Ser 2.1 (687/860) 0 0 C55 Deleterious Probably Damaging (1.00) Deleterious (0.00) 29.6 0.51 Uncertain Significance PM1, PM2, PP3
9 NALCN Het 13:102051423C > A NM_052867.4: c.55G > T p.Gly19Cys 4.96 (563/1005) 0 0 C0 Deleterious Probably Damaging (0.999) Deleterious (0.01) 27.7 0.805 Uncertain Significance PM2, PP3
Open in a new tab

Abbreviations: AF, allele frequency; URSMS, urorectal septum malformation sequence, WGS, whole genome sequencing.

4. Discussion

In this study, we report on 12 (5%) fetuses with URSMS and describe the associated pattern of malformations in them. We note complete URSMS in the majority of the fetuses (9/12, 75%), partial URSMS in two fetuses, and intermediate URSMS in one fetus. Eleven fetuses (91.6%) had multiple malformations affecting other systems and one had isolated URSMS. Overall, six fetuses had recurrent and five fetuses had unique malformations in our cohort. We identified variants of interest in four fetuses (Table 2).

There have been reports in the literature on the clinical presentation of fetuses with URSMS (Jain et al., 2008; Patil & Phadke, 2006; Tennant et al., 2014; Wheeler et al., 1997; Wheeler & Weaver, 2001) and a previous cohort from our center (Shah et al., 2016). The rate of associated anomalies of other systems ranges from 65% to 89% (Jain et al., 2008; Patil & Phadke, 2006; Tennant et al., 2014; Wheeler et al., 1997; Wheeler & Weaver, 2001). Limb malformations (e.g., club foot, polydactyly, limb reduction defects, absent/hypoplastic thumb, absent fibula, hip dislocation, cubitus valgus, genu valgum, clinodactyly, and simian creases) and cardiac anomalies (atrial septal defect, ventricular septal defect, tetralogy of Fallot, tricuspid stenosis, pulmonary valve stenosis, truncus arteriosus, atrioventricular canal defect, anomalous venous return, and patent ductus arteriosus) appear to be the most frequent (in 32% each) followed by vertebral anomalies, mainly affecting the lumbar spine in 22.8%; central nervous system anomalies (neural tube defects and holoprosencephaly) in 16.5%; gastrointestinal anomalies (tracheoesophageal fistula, esophageal atresia, small gut atresia or stenosis, Meckel's diverticulum and atresia of bile duct) in 15.7%; ventral body wall defect/omphalocele in 8.6%; single umbilical artery/urachal cyst in 7% and others (congenital diaphragmatic hernia, congenital cystic adenomatoid malformation of lung, cleft palate, perineal hernia) very rarely.

The recurrent malformations or phenotypes observed in our cohort were VATER association, limb body wall defect, neural tube defects and abdominal wall defect. Neural tube defects were more common in our small cohort. Prune-belly sequence and vertebralanal-cardiac-tracheoesophageal fistula-renal-limb (VACTERL) association were also observed with URSMS earlier (Tennant et al., 2014). Patterns of severe ventral body wall defects were studied by Vauthay et al. and they report cloacal anomalies in 76.9% (Vauthay et al., 2007). Heyroth-Griffis et al. (2007) proposed that exstrophy of cloaca, URSMS and limb body wall complex (LMBW) represented a continuous spectrum of anomalies in view of overlapping features (Heyroth-Griffis et al., 2007). LMBW, Mullerian duct aplasia-renal anomalies-cervicothoracic somite dysplasia (MURCS), oculoauriculovertebral spectrum (OAVS), omphalocele-exstrophy-imperforate anus-spinal defects (OEIS) complex, pentalogy of Cantrell (POC) and VATER/VACTERL are developmental disorders occurs during early embryogenesis (Adam et al., 2020). They are termed as recurrent constellation of embryonic malformations (RCEM) and constitute a spectrum and are likely to be causally related. We hypothesize that the URSMS also likely belongs to RCEM based on the overlapping features with LMBW, MURCS, and VACTERL. The highlight of our work is documentation of some of the rare malformations associated with URSMS such as cerebral ventriculomegaly, right aortic arch with double outlet right ventricle, fetal akinesia deformation sequence, amelia and limb contractures with spilt foot that are not described earlier, to the best of our knowledge.

Many dysmorphic features and contractures could be caused by oligohydramnios. Antenatally oligohydramnios or anhydramnios was noted in four fetuses (Fetuses 2, 3, 7, and 10) in our cohort. Fetus 2 had contractures of all major limb joints; Fetus 10 had contractures of limb joint along with short thigh, whereas facial dysmorphism was observed in Fetuses 3 and 10, which may be secondary to oligohydramnios.

One of the twins from a monochorionic diamniotic pregnancy (Fetus 9) had URSMS and associated malformations. Twinning with URSMS was noted previously in the literature (Achiron et al., 2000). The familial occurrence of URSMS is very rare and has been reported in two families (Aggarwal & Phadke, 2013; Mills & Pergament, 1997). One of them had a dominant inheritance, where the mother had mild manifestations and the child had severe URSMS (Mills & Pergament, 1997), whereas the other family had prune belly in the first sib and URSMS in the second sib suggesting a recessive pattern of inheritance (Aggarwal & Phadke, 2013). These observations suggest the existence of a (mono) genetic etiology, at least for a proportion of patients with URSMS.

The cloaca is an embryonic structure evident by the fourth week of development and is divided to form urogenital sinus and primitive rectum by sixth week of intrauterine life. Hence, we speculate the genes involved in the early development of cloaca—Sonic hedgehog (Shh), SOX2 and CDX2, which express in the cloacal epithelium; Six1 and Ey1 intrinsic regulator of mesenchyme surrounding cloaca; Gli2 and Gli3 downstream mediator of Shh and BMP signaling are likely to play a role in pathophysiology (Runck et al., 2014).

The TMEM132A missense variant identified in fetus 1 may be relevant to the persistent cloaca observed in this fetus. Tmem132a−/− mice have impaired hind limb growth and spina bifida in addition to bladder and kidney defects (Li et al., 2022). Whole embryo staining of Tmem132a−/− mice revealed Cdx2 is notably downregulated in the hindgut (Li et al., 2022). The importance of CDX2 signaling in the normal development of the cloacal epithelium is supported by the identification of damaging de novo variants in CDX2 in two unrelated patients with persistent cloaca (Hsu et al., 2018). Recently, variants in CDX2 have also been reported in two familial aggregations with phenotype ranging from sirenomelia with different degrees of urogenital malformations to isolated imperforate anus indicating its role in caudal malformations (Lecoquierre et al., 2020). Moreover, the identification of a missense variant in HOXD9 in Fetus 8 is also relevant to the Shh/CDX2 pathway. Reduction in Hoxd9 expression observed in embryonic limb buds of rats supplemented with all-trans-retinoic acid correlated with impaired Shh/Gli3 signaling and reduced Sox9/Col2a11 signaling (Hong et al., 2021). Both Shh (Seifert et al., 2009) and Gli3 (Mo et al., 2001) expression are reduced in rats with anorectal malformations (Liu et al., 2016). Additionally, a disorganization-like syndrome was noted with persistent cloaca, having an incomplete duplication of left lower limb (Al Kaissi et al., 2008), suggesting an overlap in signal defects can cause deficiencies in both tissues. The normal limb development observed in Fetus 8 suggests the HOXD9 c.277A > G variant would only urorectal development would be affected in this case, despite the association of HOXD9 with limb defects.

Moreover, The SLIT2 variant identified in Fetus 8 may relate to the unilateral renal agenesis observed during fetal evaluation. Slit2−/− mice develop multiple ureters and fused dysplastic kidneys as a result of ureteric buds, which remain inappropriately connected to the nephric duct during development (Grieshammer et al., 2004). Furthermore, heterozygous missense SLIT2 variants were identified in three unrelated patients from a cohort with congenital anomalies of the kidney and urinary tract (CAKUT), one patient with bilateral subcortical renal cysts, one patient with right multicystic dysplastic kidneys, and one patient with right renal agenesis (Hwang et al., 2015).

In Fetus 8, the identification of concomitant HOXD9 and SLIT2 missense variants prompts the hypothesis that the etiology of URSMS in this fetus is oligogenic. URSMS has been identified as a component in a few syndromes/phenotypes, which are listed in Online Mendelian Inheritance in Man along with their genetic bases: persistent cloaca and prune belly syndrome with tricho-rhino-phalangeal syndrome type II (MIM#150230) associated with 8q interstitial deletion (Ramos et al., 1992); Fanconi anemia, complementation group A (MIM# 227650) (Farrell et al., 1994); sacral agenesis with vertebral anomalies (MIM# 615709) due to biallelic variants in TBXT (Postma et al., 2014); Omphalocele-Exstrophy-Imperforate Anus-Spinal Defects (OEIS complex, MIM 258040) associated with 1p36 deletion (El-Hattab et al., 2010) and a heterozygous variants in Uroplakin 3A associated with renal dysplasia and persistent cloaca (Jenkins et al., 2005). The London Medical Database has following entities listed with exstrophy of cloaca: caudal duplication syndrome; caudal regression; diphallus plus; femoral duplication; frontonasal dysplasia-exstrophy of bladder or cloaca; Gollop-Wolfgang complex caused by BHLHA9; sirenomelia; urorectal septal defects and VATER association.

Several researchers explored the genetic basis of URSMS and related anomalies. Patients with anorectal malformations and VACTERL association or cloacal exstrophy were analyzed for variants in FGF10 following a reproducible phenotype of urorectal defect in mice; however, the data obtained were not supportive (Krüger et al., 2008). Isochromosome 18q was observed in a fetus with congenital megacystis, cloacal dysgenesis sequence and median cleft lip and palate by karyotype (Chen et al., 1998). Array comparative genomic hybridization in 17 females with cloaca identified novel copy number variations (paternally inherited duplication on 16p13.2 and a de novo deletion on 1q32.1q32.3) in two patients (Harrison et al., 2014). The latter deletion included a plausible candidate, hedgehog acyltransferase (HHAT); however, Sanger sequencing of independent patients with cloacal defects did not identify any significant variants in this gene. Prenatal diagnosis by chromosomal microarray in a pregnancy suspected with URSMS detected paternally inherited 111.8Kb deletion at 16p13.3 in the affected fetus (Pei et al., 2016). Similarly, ZNF157, SP8, ACOT9, and TTLL11 are thought to be associated with VATER/VACTERL following exome sequencing in a cohort of 21 families (Kolvenbach et al., 2021). However, further studies are required to explain the causality.

We identified heterozygous missense NALCN variants in Fetuses 3 and 9. NALCN encodes the nonselective sodium leak channel, and homozygous knockout is incompatible with life in mice (Cochet-Bissuel et al., 2014). Previously, de novo NALCN variants were observed in 14 unrelated probands with congenital contractures of the limbs and face, hypotonia and developmental delay (CLIFAHDD, MIM#616266) (Chong et al., 2015). NALCN is primarily expressed in the nervous system, suggesting its role is in movement coordination and intellectual development, rather than tissue patterning and development (Kasap et al., 2017). Phenotypes in Fetuses 3 and 9 are do not feature contractures, while hypotonia and developmental delay were not discernible in this cohort. However, scoliosis, clubfoot, and omphalocele observed in Fetus 9 are reminiscent of the additional phenotypes observed among the CLIFAHDD cohort (Chong et al., 2015).

We assume that the presence of various malformations with URSMS represent clinically diverse spectrum of perinatal lethal syndromes with URSMS. Our observations call for a concerted effort for delineation of clinically and likely etiologically heterogeneous conditions with URSMS. Genome sequencing and analysis did not identify variants in known URSMS genes, but it identifies novel candidate variants that provide the basis for future investigations. However, in some cases, no variant of interest was identified, which suggests that these fetuses may have a more complex oligo/polygenic etiology with environmental influences.

Supplementary Material

Supplementary file

Acknowledgments

The authors thank the families for their participation and support. This work was supported by the Indian Council of Medical Research, Government of India (No. 5/13/58/2015/NCD-III) and DBT/Wellcome Trust India Alliance Grant titled ‘Center for Rare Disease Diagnosis, Research and Training (Grant number: IA/CRC/20/1/600002). William G. Newman is supported by the Manchester NIHR BRC (IS-BRC-1215-20007).

Funding information

Indian Council of Medical Research, Government of India, Grant/Award Number: 5/13/58/2015/NCD-III; DBT/Wellcome Trust India Alliance Grant, Grant/Award Number: IA/CRC/20/1/600002; Manchester NIHR BRC, Grant/Award Number: IS-BRC-1215-20007

Footnotes

Conflict of Interest

The authors declare no conflict of interest.

Data Availability Statement

The data that support the findings of this study are available in the supplementary material of this article.

References

  1. Achiron R, Frydman M, Lipitz S, Zalel Y. Urorectal septum malformation sequence: Prenatal sonographic diagnosis in two sets of discordant twins. Ultrasound in Obstetrics & Gynecology. 2000;16(6):571–574. doi: 10.1046/j.1469-0705.2000.00233.x. [DOI] [PubMed] [Google Scholar]
  2. Adam AP, Curry CJ, Hall JG, Keppler-Noreuil KM, Adam MP, Dobyns WB. Recurrent constellations of embryonic malformations re-conceptualized as an overlapping group of disorders with shared pathogenesis. American Journal of Medical Genetics. Part A. 2020;182(11):2646–2661. doi: 10.1002/ajmg.a.61847. [DOI] [PubMed] [Google Scholar]
  3. Aggarwal S, Phadke SR. Recurrence of urorectal septum malformation sequence spectrum anomalies in siblings: Time to explore the genetics. American Journal of Medical Genetics. Part A. 2013;161A(7):1718–1721. doi: 10.1002/ajmg.a.35950. [DOI] [PubMed] [Google Scholar]
  4. Al Kaissi A, Strobl W, Bauer J, Landauer F, Klaushofer K, Grill F. Persistent cloaca associated with a duplicated left leg: A novel disorganization-like syndrome. Clinical Dysmorphology. 2008;17(2):137–139. doi: 10.1097/MCD.0b013e3282efe244. [DOI] [PubMed] [Google Scholar]
  5. Chen CP, Chern SR, Lee CC, Town DD. Isochromosome 18q in a fetus with congenital megacystis, intra-uterine growth retardation and cloacal dysgenesis sequence. Prenatal Diagnosis. 1998;18(10):1068–1074. [PubMed] [Google Scholar]
  6. Chong JX, McMillin MJ, Shively KM, Beck AE, Marvin CT, Armenteros JR, Buckingham KJ, Nkinsi NT, Boyle EA, Berry MN, Bocian M, et al. De novo mutations in NALCN cause a syndrome characterized by congenital contractures of the limbs and face, hypotonia, and developmental delay. American Journal of Human Genetics. 2015;96(3):462–473. doi: 10.1016/j.ajhg.2015.01.003. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Cochet-Bissuel M, Lory P, Monteil A. The sodium leak channel, NALCN, in health and disease. Frontiers in Cellular Neuroscience. 2014;8:132. doi: 10.3389/fncel.2014.00132. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. El-Hattab AW, Skorupski JC, Hsieh MH, Breman AM, Patel A, Cheung SW, Craigen WJ. OEIS complex associated with chromosome 1p36 deletion: A case report and review. American Journal of Medical Genetics. Part A. 2010;152A(2):504–511. doi: 10.1002/ajmg.a.33226. [DOI] [PubMed] [Google Scholar]
  9. Farrell SA, Paes BA, Lewis ME. Fanconi anemia in a child previously diagnosed as Baller-Gerold syndrome. American Journal of Medical Genetics. 1994;50(1):98–99. doi: 10.1002/ajmg.1320500123. [DOI] [PubMed] [Google Scholar]
  10. Grieshammer U, Le Ma AS, Plump F, Wang MT-L, Martin GR. SLIT2-mediated ROBO2 signaling restricts kidney induction to a single site. Developmental Cell. 2004;6(5):709–717. doi: 10.1016/s1534-5807(04)00108-x. [DOI] [PubMed] [Google Scholar]
  11. Harrison SM, Seideman C, Baker LA. DNA copy number variations in patients with persistent cloaca. The Journal of Urology. 2014;191(5 Suppl):1543–1546. doi: 10.1016/j.juro.2013.09.056. [DOI] [PubMed] [Google Scholar]
  12. Heyroth-Griffis CA, Weaver DD, Faught P, Bellus GA, Torres-Martinez W. On the spectrum of limb-body wall complex, exstrophy of the cloaca, and urorectal septum malformation sequence. American Journal of Medical Genetics. Part A. 2007;143A(10):1025–1031. doi: 10.1002/ajmg.a.31691. [DOI] [PubMed] [Google Scholar]
  13. Hong Q, Li XD, Xie P, Du SX. All-trans-retinoic acid suppresses rat embryo hindlimb bud mesenchymal chondrogenesis by modulating Hox D9 expression. Bioengineered. 2021;12(1):3900–3911. doi: 10.1080/21655979.2021.1940613. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Hsu JSJ, So M, Tang CSM, Karim A, Porsch RM, Wong C, Yu M, Yeung F, Xia H, Zhang R, Cherny SS, et al. De novo mutations in caudal type Homeo box transcription factor 2 (CDX2) in patients with persistent cloaca. Human Molecular Genetics. 2018;27(2):351–358. doi: 10.1093/hmg/ddx406. [DOI] [PubMed] [Google Scholar]
  15. Huang KY, Kuo KT, Li YP, Chen M, Yu CU, Shih JC. Urorectal septum malformation sequence-fetal series with the description of a new “intermediate” variant. Time to refine the terminology? American Journal of Medical Genetics. Part A. 2016;170(9):2479–2482. doi: 10.1002/ajmg.a.37788. [DOI] [PubMed] [Google Scholar]
  16. Hwang DY, Kohl S, Fan X, Vivante A, Chan S, Dworschak GC, Schulz J, van Eerde AM, Hilger AC, Gee HY, Pennimpede T, et al. Mutations of the SLIT2-ROBO2 pathway genes SLIT2 and SRGAP1 confer risk for congenital anomalies of the kidney and urinary tract. Human Genetics. 2015;134(8):905–916. doi: 10.1007/s00439-015-1570-5. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Ioannidis NM, Rothstein JH, Pejaver V, Middha S, McDonnell SK, Baheti S, Musolf A, Li Q, Holzinger E, Karyadi D, Cannon-Albright LA, et al. REVEL: An ensemble method for predicting the pathogenicity of rare missense variants. The American Journal of Human Genetics. 2016;99(4):877–885. doi: 10.1016/j.ajhg.2016.08.016. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Jaganathan K, Kyriazopoulou Panagiotopoulou S, McRae JF, Darbandi SF, Knowles D, Li YI, Kosmicki JA, Arbelaez J, Cui W, Schwartz GB, Chow ED, et al. Predicting splicing from primary sequence with deep learning. Cell. 2019;176(3):535–548.:e24. doi: 10.1016/j.cell.2018.12.015. [DOI] [PubMed] [Google Scholar]
  19. Jain D, Sharma MC, Kulkarni KK, Aggrawal S, Karak AK. Urorectal septum malformation sequence: A report of seven cases. Congenital Anomalies (Kyoto) 2008;48(4):174–179. doi: 10.1111/j.1741-4520.2008.00200.x. [DOI] [PubMed] [Google Scholar]
  20. Jenkins D, Bitner-Glindzicz M, Malcolm S, Hu CC, Allison J, Winyard PJ, Gullett AM, Thomas DF, Belk RA, Feather SA, Sun TT, et al. De novo Uroplakin IIIa heterozygous mutations cause human renal adysplasia leading to severe kidney failure. Journal of the American Society of Nephrology. 2005;16(7):2141–2149. doi: 10.1681/ASN.2004090776. [DOI] [PubMed] [Google Scholar]
  21. Kasap M, Bonnett K, Aamodt EJ, Dwyer DS. Akinesia and freezing caused by Na. The Journal of Comparative Neurology. 2017;525(5):1109–1121. doi: 10.1002/cne.24119. [DOI] [PubMed] [Google Scholar]
  22. Khong TY, Malcomson RDG. Keeling’s fetal and neonatal pathology. Springer; 2015. [Google Scholar]
  23. Kolvenbach CM, van der Ven AT, Kause F, Shril S, Scala M, Connaughton DM, Mann N, Nakayama M, Dai R, Kitzler TM, Schneider R, et al. Exome survey of individuals affected by VATER/VACTERL with renal phenotypes identifies phenocopies and novel candidate genes. American Journal of Medical Genetics. Part A. 2021;185(12):3784–3792. doi: 10.1002/ajmg.a.62447. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. Krüger V, Khoshvaghti M, Reutter H, Vogt H, Boemers TM, Ludwig M. Investigation of FGF10 as a candidate gene in patients with anorectal malformations and exstrophy of the cloaca. Pediatric Surgery International. 2008;24(8):893–897. doi: 10.1007/s00383-008-2193-x. [DOI] [PubMed] [Google Scholar]
  25. Lecoquierre F, Brehin AC, Coutant S, Coursimault J, Bazin A, Finck W, Benoist G, Begorre M, Beneteau C, Cailliez D, Chenal P, et al. Exome sequencing identifies the first genetic determinants of sirenomelia in humans. Human Mutation. 2020;41(5):926–933. doi: 10.1002/humu.23998. [DOI] [PubMed] [Google Scholar]
  26. Li B, Brusman L, Dahlka J, Niswander LA. TMEM132A ensures mouse caudal neural tube closure and regulates integrin-based mesodermal migration. Development. 2022;149(17) doi: 10.1242/dev.200442. [DOI] [PMC free article] [PubMed] [Google Scholar]
  27. Liu ZH, Li EH, Xu DL, Sun WL, Hong Y, Zhao W, Xia SJ, Jiang JT. Genetic research and structural dysplasia assessment of anorectal malformations in neonatal male rats induced by di(n-butyl) phthalate. Environmental Toxicology. 2016;31(3):261–268. doi: 10.1002/tox.22040. [DOI] [PubMed] [Google Scholar]
  28. Mills PL, Pergament E. Urorectal septal defects in a female and her offspring. American Journal of Medical Genetics. 1997;70(3):250–252. doi: 10.1002/(sici)1096-8628(19970613)70:3<250::aid-ajmg7>3.0.co;2-#. [DOI] [PubMed] [Google Scholar]
  29. Mo R, Kim JH, Zhang J, Chiang C, Hui CC, Kim PC. Anorectal malformations caused by defects in sonic hedgehog signaling. The American Journal of Pathology. 2001;159(2):765–774. doi: 10.1016/S0002-9440(10)61747-6. [DOI] [PMC free article] [PubMed] [Google Scholar]
  30. Nayak SS, Shukla A, Lewis L, Kadavigere R, Mathew M, Adiga PK, Vasudeva A, Kumar P, Shetty J, Shah H, Girisha KM. Clinical utility of fetal autopsy and its impact on genetic counseling. Prenatal Diagnosis. 2015;35(7):685–691. doi: 10.1002/pd.4592. [DOI] [PubMed] [Google Scholar]
  31. Osborn Ml, Lowe J. Guidelines on autopsy practice: Fetal autopsy (2nd trimester fetal loss and termination of pregnancy for congenital anomaly) The Royal College of Pathologists; 2017. [Google Scholar]
  32. Patil SJ, Phadke SR. Urorectal septum malformation sequence: Ultrasound correlation with fetal examination. Indian Journal of Pediatrics. 2006;73(4):287–293. doi: 10.1007/BF02825821. [DOI] [PubMed] [Google Scholar]
  33. Pei Y, Wu Q, Liu Y, Sun L, Zhi W, Zhang P. Prenatal sonographic diagnosis of urorectal septum malformation sequence and chromosomal microarray analysis: A case report and review of the literature. Medicine (Baltimore) 2016;95(45):e5326. doi: 10.1097/MD.0000000000005326. [DOI] [PMC free article] [PubMed] [Google Scholar]
  34. Postma AV, Alders M, Sylva M, Bilardo CM, Pajkrt E, van Rijn RR, Schulte-Merker S, Bulk S, Stefanovic S, Ilgun A, Barnett P, et al. Mutations in the T (brachyury) gene cause a novel syndrome consisting of sacral agenesis, abnormal ossification of the vertebral bodies and a persistent notochordal canal. Journal of Medical Genetics. 2014;51(2):90–97. doi: 10.1136/jmedgenet-2013-102001. [DOI] [PubMed] [Google Scholar]
  35. Ramos FJ, McDonald-McGinn DM, Emanuel BS, Zackai EH. Tricho-rhino-phalangeal syndrome type II (Langer-Giedion) with persistent cloaca and prune belly sequence in a girl with 8q interstitial deletion. American Journal of Medical Genetics. 1992;44(6):790–794. doi: 10.1002/ajmg.1320440614. [DOI] [PubMed] [Google Scholar]
  36. Runck LA, Method A, Bischoff A, Levitt M, Peña A, Collins MH, Gupta A, Shanmukhappa S, Wells JM, Guasch G. Defining the molecular pathologies in cloaca malformation: Similarities between mouse and human. Disease Models & Mechanisms. 2014;7(4):483–493. doi: 10.1242/dmm.014530. [DOI] [PMC free article] [PubMed] [Google Scholar]
  37. Seifert AW, Bouldin CM, Choi KS, Harfe BD, Cohn MJ. Multiphasic and tissue-specific roles of sonic hedgehog in cloacal septation and external genitalia development. Development. 2009;136(23):3949–3957. doi: 10.1242/dev.042291. [DOI] [PMC free article] [PubMed] [Google Scholar]
  38. Shah K, Nayak SS, Shukla A, Girisha KM. Spectrum of urorectal septum malformation sequence. Congenital Anomalies (Kyoto) 2016;56(3):119–126. doi: 10.1111/cga.12149. [DOI] [PubMed] [Google Scholar]
  39. Tennant PW, Glinianaia SV, Wellesley D, Draper ES, Kurinczuk JJ, Tonks AM, Tucker DF, Wreyford B, Rankin J. Epidemiology of partial urorectal septum malformation sequence (or persistent cloaca): A population-based study in seven regions of England and Wales, 1985-2010. Archives of Disease in Childhood. Fetal and Neonatal Edition. 2014;99(5):F413–F418. doi: 10.1136/archdischild-2014-306027. [DOI] [PubMed] [Google Scholar]
  40. Vauthay L, Mazzitelli N, Rittler M. Patterns of severe abdominal wall defects: Insights into pathogenesis, delineation, and nomenclature. Birth Defects Research. Part A, Clinical and Molecular Teratology. 2007;79(3):211–220. doi: 10.1002/bdra.20339. [DOI] [PubMed] [Google Scholar]
  41. Wheeler PG, Weaver DD. Partial urorectal septum malformation sequence: A report of 25 cases. American Journal of Medical Genetics. 2001;103(2):99–105. doi: 10.1002/ajmg.1510. [DOI] [PubMed] [Google Scholar]
  42. Wheeler PG, Weaver DD, Obeime MO, Vance GH, Bull MJ, Escobar LF. Urorectal septum malformation sequence: Report of thirteen additional cases and review of the literature. American Journal of Medical Genetics. 1997;73(4):456–462. [PubMed] [Google Scholar]

Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Supplementary Materials

Supplementary file
EMS195514-supplement-Supplementary_file.docx (7.3MB, docx)

Data Availability Statement

The data that support the findings of this study are available in the supplementary material of this article.

RESOURCES