Recurrence of urorectal septum malformation sequence spectrum anomalies in siblings: time to explore the genetics

A fetus of partial urorectal septum malformation sequence characterized by complete septate uterus: A case report

RATIONALE

Urorectal septum malformation sequence (URSMS) is an extremely uncommon anomaly characterized by imperforate anus accompanied by multiple genitourinary malformations. Here, we report a case of URSMS identified by the autopsy and classified into partial URSMS. Prenatal diagnosis is challenging for clinicians due to the difficulty of early identification of URSMS and the relative lack of specific features in ultrasound. We intend to share our experiences.

PATIENT CONCERNS

One fetus was indicated abdominal cystic structure, abdominal effusion and right renal pelvis separation (7 mm) by ultrasound at 28 + 1 week's gestation. After the pregnancy was terminated, the fetal tissues were performed to be tested by autopsy, copy number variation sequencing and whole exon sequencing.

DIAGNOSES

Based on the clinical characteristics, ultrasound, autopsy, and genetic test findings, the fetus was diagnosed with URSMS.

INTERVENTIONS

After genetic counseling, the couple opted to terminate her pregnancy.

OUTCOMES

The copy number variation results of the fetus showed a 0.48-MB duplication fragment of uncertain significance on chromosome 8p23.3, while the whole-exome sequencing revealed a SAL-LIKE 1 gene mutation. The autopsy of the fetus showed imperforate anusa, the abdominal cyst was further confirmed with complete septate uterus and the lower urethra and vagina converge formed a lumen.

LESSONS

Individuals with URSMS during the fetal period might be misdiagnosed due to atypical features of URSMS. Once structural abnormalities especially cystic mass of the futuses in the lower abdomen, URSMS should be considered.

Clinically diverse and perinatally lethal syndromes with urorectal septum malformation sequence

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.

Clinical and risk factor analysis of cloacal defects in the National Birth Defects Prevention Study

Cloacal exstrophy (CE) and persistent cloaca (PC) (alternatively termed urorectal septum malformation sequence [URSMS]), represent two major cloacal defects (CDs). Clinical characteristics and risk factors often are studied for both defects combined, rather than exploring if these defects have different etiologies. We enumerated clinical features for 47 CE and 54 PC (inclusive of URSMS) cases from the National Birth Defects Prevention Study. Thirty-three CE cases were classified as isolated and 14 as multiple (presence of unassociated major defects); respective totals for PC cases were 26 and 28. We compared selected child and maternal characteristics between 11,829 non-malformed controls and CE and PC cases using chi-square or Fisher's exact tests. Compared to controls, CE and PC cases were statistically more likely (p < 0.05) to be preterm; CE cases were more likely to be multiple births. We conducted logistic regression analysis to estimate odds ratios and 95% confidence intervals for any CD, CE, and PC with selected self-reported maternal prepregnancy and periconceptional (one month prior to 3 months following conception) exposures. In crude and adjusted analyses, we observed significant positive associations for any CD, CE, and PC with use of any fertility medication or assisted reproductive technology procedure. Significant positive associations observed only in crude analyses were any CD with maternal obesity or use of progesterone, any CD and CE with any x-ray, and any CD and PC with use of folate antagonist medications. Our findings provide some of the first insights into potential differing etiologies for CE and PC.

Prenatal sonographic diagnosis of urorectal septum malformation sequence and chromosomal microarray analysis: A case report and review of the literature

INTRODUCTION

Urorectal septum malformation sequence (URSMS) is a rare congenital abnormal syndrome that is caused by the incomplete division of the cloaca. Based on whether the cloaca membrane breaks down or not, the URSMS are classified as full and partial forms. The prenatal diagnosis of URSMS remains challenging because of poor recognition to this malformation and the relatively non-specific sonographic features. We report a prenatally sonographic diagnosed case of the partial URSMS, and review the literature to summarize the prenatal features.

CASE REPORT AND REVIEW

A 37-year old woman was referred at 24 weeks of gestation for fetal abdominal cyst. Detailed sonographic examination was done and revealed the vesicocolic fistula, distended colon, absence of perianal hypoechoic ring, pyelectasis, and small stomach bubble. The URSMS was suspected.Amniocentesis was done and karyotyping revealed 46,XY. Furthermore, chromosomal microarray analysis (CMA) was performed for the first time in URSMS and an alteration of 111.8Kb deletion was detected in 16p13.3 which was located inside the RBFOX1 gene. Parental studies showed that the deletion was inherited from the father who has nomal clinical phenotype.The woman elected to terminate the pregnancy at 25 weeks gestation and postmortem examination confirmed the diagnosis of partial URSMS.The published studies were reviewed and 28 cases of URSMS with conducted prenatal ultrasonography were collected in this report. The most common sonographic description, as suspicious signs of URSMS, were severe oligohydramnios or anhydramnios, urinary tract anomalies, fetal intra-abdominal cysts, and dilated bowel. Also, enterolithiasis and vesicocolic fistula were relatively infrequent but highly specific feature of URSMS.

CONCLUSIONS

URSMS is difficult to be diagnosed prenatally. However, it has characteristic features that can be detected by fetal ultrasonography, and a precise prenatal sonographic examination is crucial for diagnosing URSMS. Besides, more genomic profiling studies are needed to elucidate the causality.

Spectrum of urorectal septum malformation sequence

Urorectal septum malformation sequence (URSMS) is a rare spectrum of malformations involving various organ systems. Here, we present eight cases of URSMS, noted in autopsy, with different degrees of complexity, seven being the complete type and one being the partial type. All cases had gastrointestinal tract malformation in the form of the imperforate anus and indeterminate genitalia. Other gastrointestinal tract anomalies were anal agenesis in two cases, anorectal agenesis in two cases, and malformed lower intestinal tract in four cases. The associated renal abnormality was noted in five cases, which were unilateral renal agenesis, dysplastic kidney, hydronephrosis, horseshoe kidney, and unilateral hypoplastic ectopic kidney. External genital malformation, present in both male and female fetuses, included a knob-like structure at perineum in female fetuses, genital fold hypoplasia and penile aplasia or hypoplasia in male fetuses. Skeletal abnormalities included two cases of sacral agenesis and one case of lumbosacral dysraphism. Other anomalies included a case with alobar holoprosencephaly, truncus arteriosus with hypoplastic lungs in one case, and three cases with abdominal wall defects. It is our attempt to delineate a spectrum of abnormalities associated with URSMS.

Pathology of cloaca anomalies with case correlation

During the fourth week of human embryo development, a transient common channel known as a cloaca is formed from which three cavities with three external orifices arises. Cloaca anomalies occur when there is failure of separation of the rectum, vagina, and urethra channel resulting in a single drain into the perineum. In our previous institutional studies, Runck et al. compared human and mouse cloaca development and found early mis-patterning of the embryonic cloaca deranged hedgehog and bone morphogenetic proteins (BMP) signaling. Also, our group reported the embryological correlation of the epithelial and stromal histology found in step sections of the common channel in 14 cloaca malformations in humans. In this review, we present the pathology of a 4-year-old female with a cloaca and VACTERL complex, and summarize our current knowledge of cloaca pathology. Furthermore, we suggest that careful pathological examination of cloaca specimens in conjunction with surgical orientation may result in a better understanding of the etiology of this condition.

A case report of aphallia with urorectal septum malformation sequence in a newborn: a very rarely seen condition

Aphallia (absence of penis) is an extremely rare abnormality which has rarely been described in medical literature and can be part of the urorectal septum malformation sequence (URSMS). URSMS has hardly been reported in medical literature and includes the absence of perineal and anal openings in association with ambiguous genitalia and urogenital, colonic, and lumbosacral anomalies. This case report tells the importance of detailed examination of infants that are diagnosed with aphallia. We report a case of a newborn who was diagnosed as aphallia with the URSMS syndrome after birth. The neonate had an endocardial cushion defect (atrial septal defect and ventricular septal defect) and bilateral agenesis of the kidney. The neonate succumbed to death secondary to hypoplastic lung leading to respiratory failure.

What does fetal autopsy unmask in oligohydramnios?

OBJECTIVE

We aimed to determine the value of autopsy in fetuses with antenatally diagnosed oligohydramnios.

PATIENTS AND METHODS

We evaluated all fetal losses over a period of 6.5 years. Those with oligohydramnios on antenatal scan were critically analyzed. Oligohydramnios was defined as amniotic fluid index of less than five objectively or as an obvious lack of liquor at subjective assessment. A detailed postmortem examination was carried out in all the fetuses after obtaining an informed consent.

RESULTS

Fetal autopsy was conducted in 255 cases. Fifty-five (21.5%) fetuses were diagnosed to have oligohydramnios on antenatal ultrasonography. On analysis of antenatal causes of oligohydramnios, maternal/placental factors were noted in 18%, ultrasound findings known to affect amniotic fluid in 27% while cause remained unidentified in 54.5% of cases. On autopsy, fetal malformations were noted in 61.8% cases, intrauterine growth retardation in 21.8% fetuses and no obvious malformations in 16.3% fetuses. Renal anomalies were noted in 40% cases and non-renal malformations in 21.8% cases.

CONCLUSION

The postmortem examination helped us to identify the cause of fetal loss in 46 (83.6%) fetuses with antenatal oligohydramnios. A working diagnosis could not have been established without autopsy in 19 (34.5%) cases.

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.

A tortuous proximal urethra in urorectal septum malformation sequence?

We observed a newborn boy with urorectal septum malformation sequence. Anomalies of the genitalia and rectum were present. He expired on the first day of life, due to severe lung hypoplasia. Autopsy showed a colon that ended in a blind sac, an enlarged bladder with no grossly visible urethra, and dysplastic kidneys. A cone-shaped tissue at the usual site of the bladder outlet contained tortuous and slit-like lumina, suggesting an undeveloped proximal urethra. The urethral structure was lined by transitional epithelium with squamous metaplasia. Many small buds-lined with columnar epithelium-branched from the urethral structure. These ductal buds lined with columnar epithelium stained for prostatic acid phosphatase. Basal cells surrounding the ductal buds stained for p63 and high molecular weight cytokeratin-supporting an interpretation that the buds were early prostatic ducts with normal histology. To our knowledge, these are the first histological images of an undeveloped, obstructed urethra associated with the urorectal septum malformation sequence.