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Year : 2021  |  Volume : 10  |  Issue : 2  |  Page : 140-142

First case of sirenomelia Type III in Ukraine

Department of Pediatric Surgery, Danylo Halytsky Lviv National Medical University, Lviv, Ukraine

Date of Submission27-Jul-2020
Date of Decision13-Jan-2021
Date of Acceptance14-Jan-2021
Date of Web Publication15-May-2021

Correspondence Address:
Andriy Pereyaslov
Fedkovicha Str., 26/7, 79018 Lviv
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jcn.jcn_120_20

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Sirenomelia in monochorionic diamniotic twins is extremely rare pathology. According to the literature data, there are only 24 cases, in which one or both fetuses had sirenomelia. The incidence rate of sirenomelia ranged from 1.1 to 4.2/60,000–100,000 deliveries and associated with the high lethality during early perinatal period. Here, we present a monochorionic diamniotic twin pregnancy, where one fetus was diagnosed with sirenomelia associated with agenesia of one kidney and bladder, and the co-twin was absolutely healthy.

Keywords: Monochorionic diamniotic twins, multiple congenital malformations, Sirenomelia

How to cite this article:
Pereyaslov A, Nykyforuk O. First case of sirenomelia Type III in Ukraine. J Clin Neonatol 2021;10:140-2

How to cite this URL:
Pereyaslov A, Nykyforuk O. First case of sirenomelia Type III in Ukraine. J Clin Neonatol [serial online] 2021 [cited 2023 Mar 21];10:140-2. Available from: https://www.jcnonweb.com/text.asp?2021/10/2/140/316166

  Introduction Top

Sirenomelia, also known as mermaid syndrome, is a very rare congenital malformation, which characterized by complete or partially fused lower extremities, with the incidence rate ranged from 1.1 to 4.2/60,000–100,000 deliveries.[1],[2] There are near 300 cases of sirenomelia is known for today.[2],[3],[4] Sirenomelia is a lethal condition in the perinatal period, except for very rare instances, that hampering any intent of treatment.[2] More often sirenomelia revealed in South America, Mexico, France, and Italy.[2]

Due to the rarity of this malformation, we represented the first case of sirenomelia in one of twins in Ukraine.

  Case Report Top

A 25-year-old gravida in her first pregnancy admitted the Lviv Medical Genetics Center at 18–19-week gestation in order to predict the offspring due to the results of biochemical tests (alpha-fetoprotein [AFP] – 4.9 multiples of the median [MOM], chorionic gonadotropin – 7.2 MOM, and free E3 – 0.73 MOM).

Prenatal ultrasonography performed at the second and third trimester of pregnancy: monochorionic diamniotic twins. First fetus had a normal growth and biophysical profile; second fetus – with multiple congenital malformations: fused lower extremities with the presence of only tibiae and absence of both fibulae, and the specific arrangement of feet like sirenomelia [Figure 1]; the single kidney with the multiple cysts, absent bladder; external genitalia not visualized; hypoplastic thorax; and severe oligohydramnios. It was discordant development of monochorionic twins – discordant growth (47%).

Vaginal delivery was at terms 36–37 weeks of gestation. The first healthy male baby had a length 46 cm, weight – 2400 g, and Apgar score – 7/8 at 1 and 5 min.
Figure 1: Prenatal sonography. Two tibias (white arrows) and specific arrangement of feet's (red arrows)

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The second baby had a weight of 1940 g, a length 46 cm, and Apgar score 3/4 (at 1 and 5 min). Immediately after birth, the baby was transferred to Lviv Regional Children's Clinical Hospital “OXMATDYT”. At the first examination, the head, face, and neck were without pathology. The auscultation of heart and lung: Heart tones are muted; breathing at the left side is weakened. The abdomen is soft, without distention, and meconium was not passed. Lower extremities throughout fused, with the presence of two femurs and two tibias; external genitalia absent [Figure 2].
Figure 2: (a) Front view. (b) Posterior view. (c) Side view

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Ultrasonography showed that liver, gallbladder, pancreas, and spleen were normal. The single (possible left) hypoplastic (size 3.8 cm × 2.0 cm) kidney with hydrocaliectasis (up to 8 mm) and pyelectasis (up to 10 mm) was visualized at pelvis [Figure 3]a. Bladder was not visualized. At the right inguinal region and in the projection of the left buttock two “ovoid structures” each size 1.0 cm × 0.8 cm, that had similar structure of testis, were visualized [Figure 3]b.
Figure 3: Ultrasonography. (a) Left (?) kidney with pyelectasis (arrows); (b) testis (?

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The neonate was fed intravenously during life with the minimal volumes of fluid due to the presence of congenital renourinary anomalies and signs of renal insufficiency. There was no urine passed all time of life. With increasing signs of renal and respiratory failure, baby died at 9 days after birth.

On autopsy was revealed: thorax hypoplasia, cystic lung hypoplasia, agenesia of the right kidney and cystic dysplasia of the left kidney, bladder agenesia, agenesia of external genitalia, absence of both fibulae and hypoplastic type of intrauterine growth retardation.

  Discussion Top

Sirenomelia in twins extremely is rare pathology. According to the literature date, there are 24 cases, in which one or both fetuses had sirenomelia.[4] Among these cases, there are only 11 cases of sirenomelia in monochorionic diamniotic twins.[4]

Several classifications have been described, being the most extended that proposed by Stocker and Heifetz,[5] based on the number of fused bones, ranging from Type I, in which all bones are present to Type VII, in which only a common long bone is remaining. Our case can classify as Type III – presence of both femurs and tibiae with the absence of both fibulae.

Sirenomelia can be diagnosed by the prenatal abdominal or transvaginal ultrasonography.[6],[7] The most striking sonographic finding was the detection of malformed lower limbs, which appeared to be fused and in an atypical position.[7] In our case, we revealed fused lower limbs, absence of both fibulae, and specific feet's arrangement. In our case, sirenomelia was established at the second trimester of pregnancy, despite severe oligohydramnios that can challenge the correct diagnosis.[7]

Such in our case, the expectant management is suggested in twin pregnancies, despite there being a potential risk of preterm delivery or harm to the healthy co-twin in cases of intrauterine death of the affected twin, especially in monochorionic twins.[8] Our case was managed conservatively, and both fetuses were successfully delivered by vaginal delivery at 36–37 weeks of gestation.

In most cases, the prognosis and the life expectancy of a baby born with sirenomelia determined by the presence of concomitant birth defects. Malformations that are commonly seen with the sirenomelia include: anorectal, renal (agenesia/dysplasia), cardiac, and others.[2],[6],[8] In our case, the presence of cystic dysplasia of the single kidney that associated with bladder agenesia determined the development of renal failure and death.

The survival rate of sirenomelia is very low. Only about 1% of newborns survive the 1st week of life,[2] such as in our case. Among twins, fetus with sirenomelia was stillborn or died from multiple congenital anomalies during 1st h after birth, while normal anatomy fetus had a high alive rate in previously reported cases and our case.[4]

The cost of treatment in live-born sirenomelia is huge due to renal transplantation, life support, and other repeated surgeries.[4] Due to that, pregnant should be informed about the management and prognosis of sirenomelia. We do not support the selective termination of a sirenomelia twin that connected with high-risk premature birth of another twin.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Garrido-Allepuz C, Haro E, González-Lamuño D, Martínez-Frías ML, Bertocchini F, Ros MA. A clinical and experimental overview of sirenomelia: Insight into the mechanisms of congenital limb malformations. Dis Model Mech 2011;4:289-99.  Back to cited text no. 1
Orioli IM, Amar E, Arteaga-Vazquez J, Bakker MK, Bianca S, Botto LD, et al. Sirenomelia: An epidemiologic study in a large dataset from the international clearinghouse of birth defects surveillance and research, and literature review. Am J Med Genet C Semin Med Genet 2011;157C: 358-73.  Back to cited text no. 2
Taee N, Tarhani F, Goodarzi MF, Safdari M, Bajelan A. Mermaid syndrome: A case report of a rare congenital anomaly in full-term neonate with thumb deformity. Am J Perinatol Rep 2018:8:e328-31.  Back to cited text no. 3
Xu T, Wang X, Luo H, Yu H. Sirenomelia in twin pregnancy: A case report and literature review. Medicine (Baltimore) 2018;97:e13672.  Back to cited text no. 4
Stocker JT, Heifetz SA. Sirenomelia. A morphological study of 33 cases and review of the literature. Perspect Pediatr Pathol 1987;10:7-50.  Back to cited text no. 5
Morales-Roselló JM, Loscalzo G, Buongiorno S, Jakaitê V, Perales-Marín A. Sirenomelia, case report and review of the literature. J Matern Fetal Neonatal Med 2020 Mar 26:1-4. doi:10.1080/14767058.2020.1742693. Online ahead of print.  Back to cited text no. 6
Sepulveda W, Bornstein E, Andreeva E, Montano I, Gutierrez J, Martinez-Ten P, et al. First-trimester sonographic diagnosis of sirenomelia: A multicenter series of 12 cases and review of the literature. Prenat Diagn 2020;40:626-34.  Back to cited text no. 7
Al Yaqoubi HN, Al Badi MM, Ambu Saidi FM, Al Shafouri NST. A case of sirenomelia associated with hypoplastic left heart with a healthy co-twin: A rare entity. Case Rep Pediatr 2018;2018:3. doi: 10.1155/2018/936175.eCollection 2018.  Back to cited text no. 8


  [Figure 1], [Figure 2], [Figure 3]


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