Prenatal and postnatal imaging for early detection of sirenomelia: A case study.

Sirenomelia is a rare congenital caudal abnormality. We applied two-dimensional, three-dimensional, and color Doppler ultrasound to diagnose a fetus with sirenomelia at 12 + 6 weeks. The fetus exhibited on ultrasound fused lower limbs, two tibiae in lower legs, no fibulae, knees in retroflexion, pelvic hypoplasia, hypoplasia of the lower lumbar vertebrae and coccyx, bilateral renal agenesis, no bladder, and a single umbilical artery. The postnatal X-ray revealed a fetus with two femurs, two tibiae, and no fibula. The results of chorionic villus aspiration indicated that the fetus was male with a normal karyotype (46, XY), and the microarray results were normal.

Sirenomelia or mermaid syndrome with a cleft lip in a Tanzanian newborn: a case report.

BACKGROUND: Sirenomelia or sirenomelia sequence, also known as mermaid syndrome, is a rare congenital anomaly involving the caudal region of the body. The syndrome is characterized by partial or complete fusion of lower extremities, renal agenesis, absent urinary tract, ambiguous external genitalia, imperforate anus, and single umbilical artery. Sirenomelia is often associated with several visceral congenital malformations, rendering it invariably incompatible with extrauterine life. CASE PRESENTATION: We present the case of 22-year-old Black African woman who delivered a term newborn by caesarean section at a gestation age of 37 weeks due to obstructed labor with fetal distress. The newborn was a fresh stillbirth weighing 2100 g and had fusion of the lower extremities, a single upper limb, ambiguous genitalia, imperforate anus, and a cleft lip. The mother had made only two prenatal visits, at which she was found to be normotensive and normoglycemic. She was not screened for routine fetomaternal infections and missed supplementation for folic acid during the critical first trimester. She did not undergo any obstetric ultrasonography. The parents of the newborn were not close relatives and there was no family history of consanguinity. Further genetic testing was not performed due to lack of laboratory capacity, and post mortem examination was not permitted due to cultural taboo and restrictions relating to handling of deceased newborns. CONCLUSION: Sirenomelia is a rare congenital malformation with very poor prognosis. Specific interventions during pre-conception and early prenatal care are critical in the prevention of specific congenital anomalies. Early obstetric ultrasonography is invaluable for diagnosis of sirenomelia as well as counseling for possible termination of pregnancy.

Tracheal agenesis versus tracheal atresia: anatomical conditions, pathomechanisms and causes with a possible link to a novel MAPK11 variant in one case.

BACKGROUND: In this study we aimed to describe the morphological and pathogenetic differences between tracheal agenesis and tracheal atresia, which are not clearly distinguished from each other in the literature, and to contribute thereby to the understanding and management of these conditions. Both tracheal agenesis and tracheal atresia represent rare disorders of still unknown aetiology that cannot be detected by prenatal ultrasound. If the affected foetuses survive until birth these conditions result in respiratory failure and in futile attempts to rescue the infant's life. RESULTS: Autopsies and genetic analyses, including singleton or trio exome sequencing, were performed on five neonates/foetuses with tracheal agenesis and three foetuses with tracheal atresia. Tracheal agenesis was characterized by absence of the sublaryngeal trachea and presence of a bronchooesophageal fistula and by pulmonary isomerism and occurred as an isolated malformation complex or as part of a VACTERL association. Special findings were an additional so-called 'pig bronchus' and a first case of tracheal agenesis with sirenomelia. Tracheal atresia presenting with partial obliteration of its lumen and persistence of a fibromuscular streak resulted in CHAOS. This condition was associated with normal lung lobulation and single, non-VACTERL type malformations. Trio ES revealed a novel variant of MAPK11 in one tracheal agenesis case. Its involvement in tracheooesophageal malformation is herein discussed, but remains hypothetical. CONCLUSION: Tracheal agenesis and tracheal atresia represent different disease entities in terms of morphology, pathogenesis and accompanying anomalies due to a primary developmental and secondary disruptive possibly vascular disturbance, respectively.

Defective blastogenesis of postnatally diagnosed type VI sirenomelia in a young primigravida: A case report.

Sirenomelia is a rare lethal multi-systemic birth malformation in which the two lower limbs are replaced with a rotated single midline tail-like limb. Several hypotheses try to explain this syndrome, with the most prominent theories being the "vascular steal hypothesis" and the "defective blastogenesis hypothesis." We report a case of a baby with sirenomelia who had a single femur and a single tibia, which classify the case as type VI on Stocker and Heifetz classification. The only risk factor in our case is young maternal age. The baby had a single umbilical artery, a prominent feature of the vascular steal hypothesis. Nonetheless, it also had upper limb deformity, which can be better explained by the defective blastogenesis hypothesis. Our case supports the defective blastogenesis theory of sirenomelia more than the vascular steal hypothesis as it has both a single umbilical artery and upper limb deformity. Also, our case serves as a teaching lesson that indicates the importance of an obstetric ultrasound before a cesarean section has to be done to avoid unnecessary surgery for life incompatible congenital anomaly.

Sirenomelia: An anatomical assessment and genetic sex determination of two cases.

The etiology of sirenomelia is currently unknown. Data are limited in comparing external and internal abnormalities using modern imaging technologies and molecular genetic analysis. The purpose of the current study was designed to compare external and internal anatomical defects in two cases of sirenomelia and Potter's sequence. Considered rare, Potter's sequence is a fetal disorder with characteristic features of bilateral renal agenesis, obstructive uropathy, atypical facial appearance, and limb malformations. The internal and external malformations of two term fetuses with sirenomelia and Potter's sequence were compared using assessment of external features, radiography and MRI on internal structures, and molecular genetic studies on sex determination. Data reveal that both fetuses were male and manifested with an overlapping but distinct spectrum of abnormalities. Principal differences were noted in the development of the ears, brain, urogenital system, lower limbs, pelvis, and vertebral column. Defects of the axial mesoderm are likely to underlie the abnormalities seen in both fetuses. The first one, which had only caudal defects, was found to have a spectrum of abnormalities most similar to those associated with more severe forms of the small pelvic outlet syndrome, although the structure and orientation of the sacrum and iliae were different from previously reported cases. The other had both caudal and cranial defects, and was most similar to those described in the axial mesodermal dysplasia syndrome. Defects associated with sirenomelia can be evaluated with standard gross anatomy examination, radiology, MRI, and modified PCR techniques to determine anatomical abnormalities and the sex of preserved specimens, respectively. Evidence indicated that sirenomelia could be developed via various etiologies.

A rare case of fetal sirenomelia malformation in the third trimester with its ultrasound appearance and review of the literature.

Sirenomelia is a very rare congenital anomaly and is the most severe form of fetal caudal agenesis, characterised by partial or total fusion of the lower limbs, generally associated with severe abnormalities of the urinary and digestive systems, including disappearance of the kidneys, which can be fatal. Our aim was to diagnose this malformation as early as possible in pregnancy, in order to distinguish it from caudal regression syndrome, and to monitor the obstetric complications associated with this pathology. Given that the patient decided to carry the pregnancy to term, we succeeded in monitoring the complications of this malformative pathology. CASE PRESENTATION: We present a case of sirenomelia diagnosed in the first trimester at 29 weeks' amenorrhoea and a quarter days, in a patient with no particular pathological, toxic or psychological history, no consanguinity and in whom the clinical examination noted no particular physical or biological abnormality. CLINICAL DISCUSSION: We discuss the criteria for ultrasound diagnosis, common malformative associations and the importance of studying umbilical vascularisation using colour Doppler. CONCLUSION: Sirenomelia is a very rare congenital anomaly and is the most severe form of fetal caudal agenesis incompatible with extrauterine life. Sirenomelia should be diagnosed at the second trimester ultrasound at the latest.

Sirenomelia in Twin Pregnancy: A Case Report.

Sirenomelia is a rare congenital disorder that was once thought to be a severe case of caudal regression but is now thought to be entirely separate. It is often referred to as the "mermaid syndrome" because it causes the lower limbs to atrophy to varying degrees, giving the impression of a mermaid's tail or fin. The syndrome is often viewed as fatal due to the accompanying visceral deformities. Our case was a live born, delivered at term by caesarean section, to a 30-year-old third gravida having twin pregnancy. Examination of the baby revealed caudal dysgenesis with fusion of lower limbs, non-identifiable external genitalia and anus. The infant survived for 11 hours after birth. We report this case due to their rarity and term live birth. While sirenomelia is uncommon, the absence of distinct lower limbs on ultrasonography in the presence of oligo or anhydramnios may prompt consideration of the diagnosis of sirenomelia.

Prenatal sirenomelia diagnosis in the first trimester: A case report and literature review.

Key Clinical Message: Sirenomelia is a lethal condition in the perinatal period. The sonographic examination in the first trimester can effectively detect sirenomelia with a high degree of accuracy. Furthermore, vascular examinations using color flow imaging and augmented imaging techniques such as 3D sonography can improve diagnostic accuracy. Parents should get advice from a multidisciplinary team concerning sirenomelia care and prognosis as soon as possible. Abstract: Sirenomelia is a rare condition with an uncommon congenital malformation; its most remarkable feature is lower extremity fusion with multiple visceral anomalies. Accordingly, the appearance resembles a mermaid's tail, hence mermaid syndrome. Sirenomelia has an incidence rate of 1.5-4.2 per 100,000 births, a male-to-female 2.7:1 ratio, and shows no differences across races. The condition is generally associated with renal agenesis, exterior genitalia defects, a single umbilical artery, and an imperforate anus. Here, we describe the first sirenomelia case in our hospital; a 13-week-old fetus with conjoined lower limbs was identified by ultrasound in the first trimester. We discuss this rare case with reference to the literature and provide insights on diagnosing this condition by ultrasound.

Sirenomelia- A rare congenital anomaly: Case report.

Sirenomelia is an extremely uncommon congenital deformity in which neonate has fused lower limbs associated with various visceral malformations including urogenital and gastrointestinal tract, pulmonary hypoplasia, and potter's facies. The prevalence is 0.8 to 1 per 100,000 newborns. About 300 cases were recorded till date. We describe a case of 31-year G4P1L1A2 with previous lower segment caesarean section with gestational age of 22 weeks 5 days with anomaly scan suggestive of single live intrauterine pregnancy of 21 weeks 5 days with bilateral renal agenesis with placenta previa and no demonstrable amniotic fluid pocket seen. Her pregnancy was uneventful without any medical disorder, drug history, and no congenital anomaly in the family. Termination of pregnancy done by emergency hysterotomy and delivered anomalous foetus with fused lower limb with absent toes, low set ears, absent left ear ostium, imperforate anus, and absent external genitalia. Sirenomelia is fatal congenital anomaly with unclear etiology. Early antenatal diagnosis and termination of pregnancy is the treatment.

TMEM132A regulates mouse hindgut morphogenesis and caudal development.

Caudal developmental defects, including caudal regression, caudal dysgenesis and sirenomelia, are devastating conditions affecting the skeletal, nervous, digestive, reproductive and excretory systems. Defects in mesodermal migration and blood supply to the caudal region have been identified as possible causes of caudal developmental defects, but neither satisfactorily explains the structural malformations in all three germ layers. Here, we describe caudal developmental defects in transmembrane protein 132a (Tmem132a) mutant mice, including skeletal, posterior neural tube closure, genitourinary tract and hindgut defects. We show that, in Tmem132a mutant embryos, visceral endoderm fails to be excluded from the medial region of early hindgut, leading directly to the loss or malformation of cloaca-derived genitourinary and gastrointestinal structures, and indirectly to the neural tube and kidney/ureter defects. We find that TMEM132A mediates intercellular interaction, and physically interacts with planar cell polarity (PCP) regulators CELSR1 and FZD6. Genetically, Tmem132a regulates neural tube closure synergistically with another PCP regulator Vangl2. In summary, we have identified Tmem132a as a new regulator of PCP, and hindgut malformation as the underlying cause of developmental defects in multiple caudal structures.

Sirenomelia or "Mermaid Syndrome" in a Twin Pregnancy: A Case Report.

Sirenomelia, also known as "mermaid syndrome" or "mermaid baby syndrome," is a very rare congenital disorder. The major anomaly in this syndrome is the fusion of the lower legs, giving it a mermaid-like appearance. This syndrome consists of a range of abnormalities affecting various systems, such as the digestive, genitourinary, and musculoskeletal systems. On the basis of the severity of the syndrome, the fetus may have a single fused bone or entirely absent bones in place of a normal pair of distinct bones. In major cases, mermaid syndrome leads to stillbirths. Its occurrence in monozygotic twins is much greater than in dizygotic twins or in a single fetus. The syndrome is believed to mainly occur in cases of maternal age less than 20 years or more than 40 years, women suffering from maternal diabetes, and prenatal exposure to retinoic acid, cocaine, and water contaminated by landfills. A 22-year-old pregnant female was admitted with a history of amenorrhea for nine months (full-term twin pregnancy) and oligohydramnios for a caesarian section. This was the patient's second pregnancy. A cesarean section was done as instructed by the gynecologist. The patient delivered twin babies. In this twin pregnancy, the first baby was normal and healthy, while the second baby was stillborn and suffered from mermaid syndrome.

A case of sirenomelia associated with atrial septal defect: A rare case report.

Introduction: and importance: Sirenomelia is a life-threatening condition caused by a rare developmental abnormality. According to the research, the incidence of sirenomelia is estimated to be between 1.5 and 4.2 per 100,000 newborns. Around 15% of cases of sirenomelia are related to a twin pregnancy, most commonly in monozygotic cases, with a 7% incidence. We're reporting on a mermaid syndrome case involving twins, one of whom was healthy and the other had sirenomelia. Case presentation: An 18-year-old female and her first child arrived at the hospital maternity ward, and she had never been there before, and when an ultrasound was performed, it was discovered that she had two babies in her womb and on of them has clung to each other's legs, and a by elective cesarean section was performed to remove the babies, which resulted in the extraction of two boys, one of whom is healthy and the other is clinging to each other's legs. Clinical discussion: Sirenomelia is a deadly congenital condition that affects the caudal part of the embryonic body. Although the most evident feature is the fusing of the lower limbs, Approximately 49.5 percent of pregnancies are terminated voluntarily due to fetal malformations, according to reports. The abnormality is thought to be caused by a combination of genetic predisposition and a trigger element in the environment, while the exact cause is unknown and thought to be complex. In cases of surviving sirenomelia, treatment can be administered using a multidisciplinary approach. Conclusion: Mermaid Syndrome is a fatal congenital abnormality with a bleak outlook. Sirenomelia can be diagnosed by ultrasonography. Oligohydramnios and fused lower limbs are important symptoms that aid in diagnosis during the first trimester of pregnancy, with probable termination of the pregnancy indicated if identified early.

Sirenomelia: A case report.

Sirenomelia also known as mermaid syndrome is a partial or complete fusion of lower extremities associated with visceral anomalies. It is a rare anomaly with a poor prognosis. Maternal age less than 20 years, maternal diabetes mellitus, and monozygotic twinning are some of the known risk factors. Diagnosis can be made via antenatal ultrasound or typical physical appearance after birth. A 2200 g baby was born from 18-year-old non-consanguineous mother via assisted breech delivery. The baby had fused lower limbs with 10 toes, absent external genitalia, and a single umbilical artery. It was small for gestational age. The baby was passed away after 30 min of birth. Young maternal age (18 years) was the identified risk factor for sirenomelia in this case. We recommend an early routine ultrasound anomaly scan in all pregnant women particularly for early detection and termination of pregnancy as the prognosis is poor. Avoiding teenager pregnancy and strict control of blood sugar in diabetic mothers can decrease this anomaly.

Six-month survival of a monochorionic monoamniotic twin with sirenomelia.

BACKGROUND: Sirenomelia is a congenital malformation of the lower body characterized by a single midline lower limb and severe urogenital and gastrointestinal malformations. Sirenomelia is rare (estimated incidence of approximately 1/100,000) and usually lethal in the perinatal period. CASE: A 2,042 g Japanese male infant, one of monochorionic monoamniotic twins, was born at 34 weeks of gestation by elective caesarean section. Sirenomelia was prenatally diagnosed. Single midline lower limb, bilateral dysplastic kidneys, an omphalomesenteric fistula, colon atresia, imperforate anus, indiscernible genital structures, and myelomeningocele were detected at birth. The amniotic fluid volume was normal throughout the pregnancy course, which led to appropriate lung maturation of the twin with sirenomelia. Although renal replacement therapy was initiated soon after birth, stable peritoneal dialysis was difficult because of the limited intraperitoneal space, and the infant frequently developed peritonitis. He died of sudden cardiorespiratory arrest at 6 months of age. Postmortem examination showed bilateral dysplastic kidneys, agenesis of the ureters and urinary bladder, abnormal branching and agenesis of the distal colon, bilateral inguinal hernias, and small testes. CONCLUSION: Infants with sirenomelia, even those with end-stage kidney disease at birth, may survive if they have a stable cardiorespiratory status at birth and renal replacement therapy is appropriately initiated.

Sirenomelia, case report and review of the literature.

We present a case of sirenomelia diagnosed in the first trimester of pregnancy. The ultrasound examination showed fused lower extremities and an anechoic structure in the lower abdomen that is clue in the early diagnosis. The postmortem study showed the existence of a single umbilical artery (vitelline artery), with an origin in the abdominal aorta. This finding not only explained the presence of a vascular steal with subsequent underdeveloped of pelvic organs, but also differentiated this condition from caudal regression syndrome.

Sirenomelia with associated systemic anomalies - an autopsy report in a full term neonate.

The mermaid syndrome, also known as sirenomelia, is considered an extremely rare congenital developmental disorder characterized by anomalies of the lower spine and lower limbs. Affected babies are born with partial or total leg fusion. Sirenomelia is thought to affect one in every 60,000 to 100,000 infants. We report a case of sirenomelia occurring in a 28-year-old multiparous woman, a heavy smoker with gestational diabetes. In the other 5 pregnancies, however, she gave birth to normal babies. The post mortem examination completed the diagnosis, revealing also multiple malformations of several systems: respiratory, gastro-intestinal, genito-urinary and cardiovascular. In our full term neonate case with grade VI sirenomelia, the presence of a single umbilical artery plus the abdominal aorta with an aberrant trajectory that ends in the umbilical cord differentiates this condition from caudal regression syndrome and also explains the under-development of pelvic organs (secondary to vascular steal phenomena).

The broader phenotypic spectrum of congenital caudal abnormalities associated with mutations in the caudal type homeobox 2 gene.

The caudal type homeobox 2 (CDX2) gene encodes a developmental regulator involved in caudal body patterning. Only three pathogenic variants in human CDX2 have been described, in patients with persistent cloaca, sirenomelia and/or renal and anogenital malformations. We identified five patients with de novo or inherited pathogenic variants in CDX2 with clinical phenotypes that partially overlap with previous cases, that is, imperforate anus and renal, urogenital and limb abnormalities. However, additional clinical features were seen including vertebral agenesis and we describe considerable phenotypic variability, even in unrelated patients with the same recurrent p.(Arg237His) variant. We propose CDX2 variants as rare genetic cause for a multiple congenital anomaly syndrome that can include features of caudal regression syndrome and VACTERL. A causative role is further substantiated by the relationship between CDX2 and other proteins encoded by genes that were previously linked to caudal abnormalities in humans, for example, TBXT (sacral agenesis and other vertebral segmentation defects) and CDX1 (anorectal malformations). Our findings confirm the essential role of CDX2 in caudal morphogenesis and formation of cloacal derivatives in humans, which to date has only been well characterized in animals.

Mermaid syndrome associated with VACTERL-H syndrome.

Mermaid syndrome or sirenomelia is an extremely rare congenital malformation with an incidence between 1.5 and 4.2 per 1,000,000 pregnancies. Association of mermaid syndrome with VACTERL-H syndrome is extremely rare, with only two cases reported so far in the literature. We present a new case of type I sirenomelia associated with VACTERL-H syndrome and review the relevant literature. A 15-year-old female patient was admitted to the Department of Pathological Pregnancy at St George University Hospital, Plovdiv with progredient abortion during her first pregnancy. She had low socioeconomic status, negative history of concomitant diseases and addictions. The patient avoided prophylactic intake of folic acid during her pregnancy. Prenatal ultrasound found a malformative fetus. Consequently, magnetic resonance imaging was performed which established the presence of hydrocephalus and defects in the lower part of the spine. These pathological findings indicated interruption of pregnancy at 20 weeks of gestation. The fetopathological examination found sirenomelia type I associated with myelomeningocele, hydrocephalus, anal imperforation, single umbilical artery, bilateral renal and ureteric agenesis, bladder agenesis, tracheo-esophageal fistula, agenesis of external genitals, monkey fold of the left palm of the hand, also known as VACTERL-H syndrome.Our case demonstrates that mermaid syndrome and VACTERL-H syndrome represent different manifestations of a single pathological process that results in disorders of the blastogenesis at different stages during embryonic development.

In search of the earliest images of symmelia in works of art.

Symmelia (alias sirenomelia, mermaid malformation) is one of the most distinctive malformations which, not surprisingly, has attracted the attention of many artists, writers and other observers of the human condition. Works of art depicting symmelia date back at least two millennia. Some are anatomically based while others are more fanciful creations intended to stir the imagination. The figure of Atargatis as a mermaid on a first century BC coin is one of the earliest known images of symmelia. A nearly 2000-year-old Native American pottery figure representing an infant with symmelia is another.

Successful Expectant Management of the Anomalous Fetus with Sirenomelia in Twin Pregnancy: A Case Report and Literature Review.

BACKGROUND: Sirenomelia is a rare congenital defect. Its management during pregnancy and after delivery is becoming a controversial issue because of its complex nature and management outcome. The possibility of expectant management in the sirenomelia twin drove us to write this case report. CASE PRESENTATION: We report a case of successful expectant management in twin sirenomelia which was diagnosed in the second trimester. Prenatal counseling of the couple by a multi-disciplinary team regarding the diagnosis, treatment, and prognosis of the sirenomelia twin was done. The mother gave birth, at term, to one normal and one sirenomelia neonate by cesarean section. CONCLUSION: Expectant management of sirenomelia one in twin pregnancy is advisable in a resource-limited setting.