Sirenomelia in an identical twin: a case report

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.

Dichorionic twin pregnancy with sirenomelia and chromosomal anomaly in 1 fetus: A case report

RATIONALE

Sirenomelia is a rare congenital malformation that threatens fetal survivals. The cases in which twin with sirenomelia and chromosomal abnormality have been seldomly reported. We reported a dichorionic twin case in which one twin had sirenomelia, the other twin had a normal phenotype, and they had different chromosomal abnormalities.

PATIENT CONCERNS

The abnormal twin was found at 22 weeks by ultrasound. The sirenomelia fetus was complicated with a thoracic stenosis, enlarged rectum without anal opening, the absence of bilateral kidneys, a single umbilical artery, a single lower limb, the abnormal curvature of spine, double outlet of right ventricle, which were the indicatives of the chromosome detection.

DIAGNOSIS

The copy number variation of the sirenomelia fetus was detected as a deletion of 4.8Mb in 11p11.12-11q11. The co-twin was found with del(Y)(q11.223q11.23), which was as the same as his father's. The mother had normal chromosome. The parents had normal phenotypes. It was firstly reported a microdeletion with sirenomelia fetus.

INTERVENTIONS

There was no specific treatments for the twins.

OUTCOMES

Intrauterine death of the sirenomelia fetus was found at 27 weeks and postnatal death after inevitable abortion happened to the co-twin.

LESSONS

Prenatal ultrasound was responsible for recognizing sirenomelia, and the detailed ultrasound scanning and chromosome detection should be done for the co-twin. The etiology of sirenomelia remains unclear, and genetic detection is also necessary for its pathogenesis research.

Sirenomelia in twin pregnancy: A case report and literature review

RATIONALE

Sirenomelia is a very rare congenital malformation and characterized by fused lower extremities, oligohydramnios, renal agenesis, absent urinary tract and external genitalia, single umbilical artery, and imperforate anus. Ultrasonography is an optimal method for prenatal screening and diagnosis of sirenomelia. The incidence of sirenomelia in the twin pregnancy is extremely low.

PATIENT CONCERNS

We reported a case of 1 twin with sirenomelia in dichorionic-diamniotic twin pregnancy after in vitro fertilization and embryo transfer.

DIAGNOSES

The sirenomelia twin was diagnosed at the 2nd trimester by ultrasonic examination and complicated with oligohydramnios and a single umbilical artery, another twin was normal.

INTERVENTIONS

A regular and careful antenatal care was conducted. The parents refused to examine the chromosome of sirenomelia twin, and the chromosomal microarray analysis of the amniotic fluid sample was only achieved in the normal anatomy twin after extensively counseled by the multi-disciplinary team.

OUTCOMES

At 34+2 gestational weeks, the demise of the malformed twin occurred, while fetal heart rate monitoring of the normal twin was abnormal, and an emergency cesarean section was performed. A healthy male baby was delivered with Apgar scores of 10 and 10 at 1 and 5 minutes, respectively. The mother and the baby were followed up and are in good health until now.

CONCLUSION

Sirenomelia is a lethal condition in the perinatal period. Early antenatal diagnosis is very important. Voluntary selective termination of sirenomelia 1 in twin pregnancy may be advised. Expecting parents should be counseled by the multidisciplinary team about the management and prognosis of the sirenomelia.

Discordant malformation in a monozygotic pregnancy: abdominoschisis and sirenomelia

Congenital malformations occur in up to 10% of monochorionic twins and are usually discordant. Body wall defect (BWD) is a rare entity of very low prevalence, defined as a combination of various malformations, including fetal body mutilations of thoracic and/or abdominal organs that can be caused by amniotic rupture early in embryonic development. Sirenomelia is a form of caudal regression syndrome that presents with lower limb fusion, among other anomalies. In this report, we will present a second trimester monochorionic diamniotic pregnancy, with BWD-abdominoschisis in one fetus and sirenomelia in the other one. Amniotic bands could not be found. Of particular importance in respect to both malformations is the timing of the insult that could have caused both anomalies.

Sirenomelia type VI (sympus apus) in one of dizygotic twins at Chiang Mai University Hospital

Those born with sirenomelia, a rare congenital anomaly, have features resembling a mermaid. Characteristics of sirenomelia are a single lower limb, sacral and pelvic bone defects, and anorectal and urogenital malformations. There is an increased incidence of sirenomelia in males and twins. This case was a preterm male, dizygotic twin and product of in vitro fertilisation. The baby was born by caesarean section due to breech presentation. He was found to have a fused lower extremity and absent external genitalia and anus. The baby passed away shortly after birth due to severe respiratory failure. Radiographic findings showed small lung volume and pneumothoraces. There were multiple segmental fusions of the vertebrae. Single femur and single tibia were presented in a fused lower limb. Autopsy demonstrated large intestinal atresia, intra-abdominal testes, absence of kidney, ureter and bladder, single umbilical artery, agenesis of blood vessels at lower extremity and agenesis of sacrum and coccyx.

Sirenomelia: a new type, showing VACTERL association with Thomas syndrome and a review of literature

Sirenomelia or "mermaid syndrome" is a rare congenital anomaly known since antiquity. This congenital anomaly is defined as a polymalformative syndrome that associates major muscle and skeleton abnormalities (unique lower limbs) with visceral abnormalities (unilateral or bilateral renal agenesis, anomalies of the abdominal vascularisation). This phenotype, typical of sirenomelia syndrome, may be more or less severe. The pathogenic mechanisms of this syndrome are still debated and its etiology remains unknown. We report here a new type of sirenomelia that we observed in a fetus belonging to the collection of the Department of Anatomy of Reims, which led us to perform a comprehensive review of the literature on the subject: this type has never been reported and cannot be classified according to the Stocker and Heifetz classification. Moreover, this case also presents a VACTERL association with Thomas syndrome.

Sirenomelia: a review on embryogenic enviromental theories, novel three-dimensional ultrasound imaging and first trimester diagnosis in a case of mosaic 69,XXX/46,XX fetus

PURPOSE

Sirenomelia is caused by atrophy of the lower extremities that is commonly associated with gastrointestinal and urogenital malformations.

METHODS

Embryogenic environmental theories and systematic review of the literature are reported.

RESULTS

Genetic basis of the condition has been demonstrated in the animal model. In humans, association with de novo balanced translocation has only recently been documented.

CONCLUSIONS

A case of triploidy mosaic fetus with sirenomelia and posterior fossa anomaly diagnosed at first trimester using novel three-dimensional ultrasound imaging techniques is presented.

Sirenomelia in a Cameroonian woman: a case report and review of the literature

Sirenomelia is a rare congenital malformative disorder characterized by fusion of the lower limbs giving a characteristic mermaid-like appearance to the affected foetus. We report a case of sirenomelia occurring in a 19 year old Cameroonian woman following premature rupture of membranes and associated cord prolapse. This is the first documented case in this country. We highlight some of the cultural myths associated with this disorder and discuss our findings relative to the present literature and related controversies on its etiopathogenesis.

Sirenomelia: an epidemiologic study in a large dataset from the International Clearinghouse of Birth Defects Surveillance and Research, and literature review

Sirenomelia is a very rare limb anomaly in which the normally paired lower limbs are replaced by a single midline limb. This study describes the prevalence, associated malformations, and maternal characteristics among cases with sirenomelia. Data originated from 19 birth defect surveillance system members of the International Clearinghouse for Birth Defects Surveillance and Research, and were reported according to a single pre-established protocol. Cases were clinically evaluated locally and reviewed centrally. A total of 249 cases with sirenomelia were identified among 25,290,172 births, for a prevalence of 0.98 per 100,000, with higher prevalence in the Mexican registry. An increase of sirenomelia prevalence with maternal age less than 20 years was statistically significant. The proportion of twinning was 9%, higher than the 1% expected. Sex was ambiguous in 47% of cases, and no different from expectation in the rest. The proportion of cases born alive, premature, and weighting less than 2,500 g were 47%, 71.2%, and 88.2%, respectively. Half of the cases with sirenomelia also presented with genital, large bowel, and urinary defects. About 10-15% of the cases had lower spinal column defects, single or anomalous umbilical artery, upper limb, cardiac, and central nervous system defects. There was a greater than expected association of sirenomelia with other very rare defects such as bladder exstrophy, cyclopia/holoprosencephaly, and acardia-acephalus. The application of the new biological network analysis approach, including molecular results, to these associated very rare diseases is suggested for future studies.

The sirenomelia sequence: a case history

We report a case of sirenomelia sequence observed in an incident of preterm labor during the 29th gestational week. According to some authors, this syndrome should be classified separately from caudal regression syndrome and is likely to be the result of an abnormality taking place during the fourth gestational week, causing developmental abnormalities in the lower extremities, pelvis, genitalia, urinary tract and digestive organs. Despite recent progress in pathology, the etiopathogenesis of sirenomelia is still debated.

Sirenomelia (mermaid syndrome): an infant from parents who used a special form of snuff

We report the first case of a fetus with sirenomelia or mermaid syndrome, whose Afghanian parents were heavy user of a special form of snuff. The case was diagnosed as a mermaid syndrome but some of the features were common to both symmelia dipus and symmelia apus, for example, the single lower extremity had the normal femur, tibia and fibula, but the single foot was rotated medially. The digestive tube ended to a massive closed saclike structure and the anus was absence. The external genital organs were rudiment and the normal testes were undescended. Aorta was divided to branches, such that the external iliac arteries were very small in comparison to the internal iliac arteries. Inferior Vena cava was placed on to the left side of the aorta and unlike the majority of reported mermaid syndrome, the bladder was present. So, the researchers believe that the present case is a rare variant of the mermaid syndrome.

[Fetal bone and joint disorders]

The article discusses the physiology and pathology of fetal bone and joint development and functions. The bones provide static support for the body. The skull and the bones of spinal column encase the central and part of the peripheral nervous system. The ribs and the sternum shield the heart and the lungs, while the bones of the pelvis protect the intraabdominal organs. Pathological changes of these bony structures may impair the functions of the respective systems or internal organs. Movements of the bones are brought about by muscles. The deriving motions are facilitated by joints. Bony anomalies of the extremities limit their effective functions. Apart from skeletal and joint abnormalities, akinesia may also be caused by neurological, muscular and skin diseases that secondarily affect the functions of bones and joints. Such pathological changes may lead to various degrees of physical disability and even to death. Some of the mentioned anomalies are recognizable in utero by ultrasound. The diagnosis may serve as medical indication for abortion in those instances when the identified abnormality is incompatible with independent life.

Multidisciplinary surgical approach to a surviving infant with sirenomelia

Sirenomelia is an extremely complex and rare malformation with different degrees of lower-extremities fusion associated with gastrointestinal, musculoskeletal, vascular, cardiopulmonary, and central nervous system malformations. In the English literature, there are only 5 reports of infants surviving with this condition. In our case, a 2540-g female infant was born with normal vital signs, no facial dysmorphism, and a complete soft tissue fusion of the lower limbs, from perineum to ankles. Radiologic examinations revealed an intestinal atresia and a single pelvic kidney, with a unique ureter, 2 femurs, 2 tibias, 2 fibulas, and 2 feet (simpus dipus). At 7 months of age, a multidisciplinary surgical team achieved complete separation of the lower limbs, with independent vascular and nerve supplies. At the time of this writing, the infant was 28 months old and had a regular growth curve. Many future reconstructive surgeries have been planned to achieve an acceptable quality of life for this infant.

Beyond the myth: the mermaid syndrome from Homerus to Andersen. A tribute to Hans Christian Andersen's bicentennial of birth

Mermaid or sirens have been part of the cultural tradition of the sailors during the first expeditions in the western world. The Siren's Myth appeared for a first time with Homer, who described in the Odyssey some singing creatures that lured the enchanted sailors to death. More frequently described with a bird body and a female head, sometimes the female part was extended to torso, with arms prolonged in sturdy claws. In the Latin literature Publius Ovidius Naso presented in the Métamorphoses these creatures. Proposed ethymology for the word "siren" seems to confirm the prerogatives of these creatures, related to magnetism, seduction, charm. The first figuration of Sirens resembling to fish-women was in the second century bc. Hans Christian Andersen provided to leave us the strongest legend of Siren in the well-known fairy tale "The Little Mermaid". Following this story, Sirens are definitely considered as beautiful half-fish women who lived in the bottom of the sea, having a lovely voice to be used when they rise up to allow sweeter the agony of the wrecked sailors. Beyond the Myth, may the Siren really exist? It can be hypothesized that these creatures probably were individuals affected by sirenomelia. In our literature and medical review, we describe the etiology of the disease, and we illustrated the anatomical features of fetuses affected by this pathology using MDCT 3D reconstructions. Syrenomelia is a condition not compatible with the normal life, however nine cases of "mermaid" survived to reconstructive surgery have been reported until now. In our report we also presented a case of survival baby girl affected by sirenomelia, before and after surgery, with correlative radiologic imaging findings. The most important characteristic that seems to allow survival of the affected individuals is the presence of one functional kidney, displaced in pelvis. As so dramatically tragic was the history of the Andersen Little Mermaid, so unattended pleasant would be the destiny of a modern mermaid, who can hope to finally marry her prince, without the risk to "loose her head", as the Copenhagen City's Symbol did in the past years, for a story beyond the Myth.

Two cases of a fetus with sirenomelia sequence

We report two cases of a fetus with sirenomelia sequence which showed oligohydramnios and a single umbilical artery. The first case was of a single fetus with symelia apus and only one leg. Prenatal diagnosis of this case was possible. The second case was of a dichorionic-diamniotic twin pregnancy in which one fetus had symelia dipus with two fused lower extremities. Prenatal diagnosis of the condition was not made. In both cases, the fetuses died shortly after birth from respiratory distress due to severe pulmonary hypoplasia. Absence of urinary tract, imperforate anus, and spine deformity were confirmed in both cases. Although prenatal diagnosis of symelia dipus seems difficult, this condition must be considered in a fetus with severe oligohydramnios.

Magnetic resonance imaging, computed tomography, and conventional X-ray in 3 cases of symmelia

BACKGROUND

Symmelia is a rare birth defect, often combined with severe malformations of the urogenital system and the lower gastrointestinal tract. Additionally, a deformed pelvis and various degrees of separation of the lower limbs are present.

CASES

We report the examination findings of 3 autopsy specimens of symmelia using magnetic resonance imaging (MRI) and computed tomography (CT) with 3-dimensional (3D) reconstructions, and conventional X-ray.

CONCLUSIONS

MRI and CT with the addition of 3D visualization can be used additionally with autopsy and conventional X-ray images in the investigation of such complex anatomical abnormalities.

Mermaid syndrome: virtually no hope for survival

Sirenomelia, also called the mermaid syndrome is a severe malformation involving multiple organs and characterized by partially or completely developed lower extremities fused by the skin. The birth of a "mermaid" is very rare (1.2-4.2 cases for 100,000 births); most are stillborn, or die at or shortly after birth. The case of a living female neonate with dipodic simelia (fusion of well-developed legs) is presented. No prenatal diagnosis was made and the newborn had an uneventful neonatal course following Cesarean section delivery. The complex and striking malformation was obvious at birth and further evaluation revealed very poorly functioning kidneys, associated with abnormal anorectum, urogenital tract, and external genitalia, as well as a pelvic malformation. Supportive care was applied because of the poor prognosis and the child died at 7 weeks of age, due to renal failure.

Sirenomelia: the mermaid syndrome

Sirenomelia, or mermaid syndrome, is the extreme form of caudal regression syndrome. We present another case of this fascinating anomaly with fused lower limbs, absent external genitalia, and absent genitourinary system. The patient could not be salvaged because of bilateral renal agenesis. Detailed autopsy findings and a review of the literature are presented.

A fetus with sirenomelia, omphalocele, and meningomyelocele, but normal kidneys

Sirenomelia, which has been reported for more than 450 years, is the most severe form of caudal dysplasia. This disorder is classically associated with agenesis or severe dysplasia of the urinary tract. A 27-year-old gravida 3 para 0020 presented at 19 weeks' gestation with monoamniotic twins, one normal and one with sirenomelia. The pregnancy miscarried following invasive diagnostic testing. Autopsy confirmed the findings of sirenomelia, meningomyelocele, omphalocele, persistent cloaca, and two normal kidneys. The abnormalities accompanying sirenomelia appear as a spectrum. The pathogenic theories of sirenomelia are reviewed in light of this case with normal kidneys.