International Journal of Anatomy and Research

Welcome to International Journal of Anatomy and Research




Type of Article: Case Report

Year: 2015 | Volume 3 | Issue 4 | Page No. 1669-1674

Date of Publication: 31-12-2015



Parimala Sirikonda *1, Nalluri Himabindu 2.

*1 Assistant Professor, Department of Anatomy, Bhaskar Medical College, Yenkapally, Moinabad, Telangana, India.
2 Associate Professor, Department of Anatomy, Bhaskar Medical College, Yenkapally, Moinabad, Telangana, India.

Address: Dr. Parimala Sirikonda, Assistant Professor, Department of Anatomy, Bhaskar Medical College, Yenkapally, Moinabad, Telangana, India.


Sirenomelia also known as mermaid syndrome, characterized by fused lower limbs, is a lethal and rare congenital abnormality. This is an extreme example of caudal regression syndrome caused by vascular steal of single umbilical artery. Sirenomelia is found approximately one in 100,000 live births and is usually fatal because of complications associated with pulmonary hypoplasia, abnormal development of the kidneys and urinary bladder.  Most of the cases are associated with maternal diabetes and single umbilical artery.
We report a case of sirenomelia terminated at 21weeks of gestation due to multiple congenital abnormalities. Antenatal scan of a25-year old primi revealed a single live fetus of 21 weeks gestation with severe olighydramnios, non-visualization of kidneys and bladder and lower part of the spine. This pregnancy was terminated and the specimen sent to the department of anatomy for fetal autopsy. On external examination,a tail like rudimentary single midline lower limb without foot was noted. There were no external genitalia and anal orifice. Internal examination revealed hypoplastic lungs, atrial septal and ventricular septal defects, aberrant right subclavian artery, hypoplastic abdominal aorta distal to the single umbilical artery, complete agenesis of urinary system, rectal agenesis and rudimentary indeterminate gonads.
We would like to discuss the clinical features, etio- pathogenesis and review of literature of sirenomelia. Early diagnosis and termination of this lethal congenital anomaly results in minimizing the trauma related to the termination of pregnancy at advanced gestation.
KEY WORDS: Sirenomelia, Caudal regression syndrome, vascular steal, maternal diabetes, single umbilical artery.


  1. Bernard Duhamel et al, From the mermaid to Anal Imperforation: The syndrome of caudal Regression. 1960
  2. Johnson B. L. Sirenomelia (Mermaid Fetus). Br. J. Clin. Pract. 1966;20:198–201.
  3. Martinez-Frias M. L.,Cucalon F., Urioste M. New case of limb body-wall complex associated with sirenomelia sequence. Am. J. Med. Genet. 1992;44:583–585.
  4. Murphy J. J., Fraser G. C., Blair G. K. Sirenomelia: case of the surviving mermaid. J. Pediatr. Surg. 1992;27:1265–1268. 
  5. Stocker J. T., Heifetz S. A. Sirenomelia.A morphological study of 33 cases and review of the literature. Perspect.Pediatr.Pathol. 1987;10:7–50. 
  6. Kallen B., Castilla E. E., Lancaster P. A., Mutchinick O., Knudsen L. B., Martinez-Frias M. L., Mastroiacovo P., Robert E. The cyclops and the mermaid: an epidemiological study of two types of rare malformation. J. Med. Genet. 1992;29:30–35. 
  7. Goodlow O. G., Sibley R. I., Allen B. G., Kamanda W. S., Gullattee A. C., Rayfield W. C. Sirenomelia: mermaid syndrome. J. Natl. Med. Assoc. 1988;80:343–346.
  8. Heifetz S. A. Single umbilical artery. A statistical analysis of 237 autopsy cases and review of the literature. Perspect.Pediatr.Pathol. 1984;8:345–378.
  9. Stevenson R. E., Jones K. L., Phelan M. C., Jones M. C., Barr M., Jr, ClericuzioC., Harley R. A., Benirschke K. Vascular steal: the pathogenetic mechanism producing sirenomelia and associated defects of the viscera and soft tissues. Pediatrics 1986;78:451–457.
  10. Martinez-Frias M. L., Bermejo E., Rodriguez-Pinilla E., Prieto D. Does single umbilical artery (SUA) predict any type of congenital defect? Clinical-epidemiological analysis of a large consecutive series of malformed infants. Am. J. Med. Genet. 2008;146A:15–25. 
  11. Opitz J. M., Zanni G., Reynolds J. F., Jr, Gilbert-Barness E. (2002). Defects of blastogenesis.Am. J. Med. Genet. 2002;115:269–286.
  12. Thottungal A. D., Charles A. K., Dickinson J. E., Bower C. Caudal dysgenesis and sirenomelia-single centre experience suggests common pathogenic basis. Am. J. Med. Genet. 2010;152A:2578–2587. 
  13. Jaiyesimi F., Gomathinayagam T., Dixit A., Amer M. Sirenomelia without vitelline artery steal. Ann. Saudi Med. 1998;18:542–544.
  14. Duesterhoeft S. M., Ernst L. M., Siebert J. R., Kapur R. P. Five cases of caudal regression with an aberrant abdominal umbilical artery: further support for a caudal regression-sirenomelia spectrum. Am. J. Med. Genet. 2007;143A:3175–3184.
  15. Kjaer K. W., Keeling J. W., Opitz J. M., Gilbert-Barness E., Hartling U., Hansen B. F., Kjaer I. Sirenomelia sequence according to the distance between the first sacral vertebra and the ilia. Am. J. Med. Genet. 2003;120A:503–508.
  16. Kallen B., Winberg J. Caudal mesoderm pattern of anomalies: from renal agenesis to sirenomelia. Teratology 1974;9:99–111.
  17. Rodriguez J. I., Palacios J., Razquin S. Sirenomelia and anencephaly. Am. J. Med. Genet. 1991;39:25–27.
  18. Rodriguez J. I., Palacios J. Craniorachischisistotalis and sirenomelia. Am. J. Med. Genet. 1992;43:732–736.
  19. Drossou-Agakidou V., Xatzisevastou-Loukidou C., Soubasi V., Kostopoulou E., Laporda A., Pantzaki A., Agelidou S., Kremenopoulos G. Rare manifestations of sirenomelia syndrome: a report of five cases. Am. J. Perinatol. 2004;21:395–401.
  20. Davidson E. H. Later embryogenesis: regulatory circuitry in morphogenetic fields. Development  1993;118:665–690.
  21. Carlos Gamido – Allepuz et al. A Clinical and experimental overview of Sirenomelia: insight into the mechanism of congential limb malformations. Disease models & Mechanisms 2011;4:289-299.
  22. Passarge E., Lenz W. (1966). Syndrome of caudal regression in infants of diabetic mothers: observations of further cases. Pediatrics 1966;37:672–675.
  23. Kalter H. Case reports of malformations associated with maternal diabetes: history and critique. Clin.Genet. 1993;43:174–179.
  24. Twickler D., Budorick N., Pretorius D., Grafe M., Currarino G. Caudal regression versus sirenomelia: sonographic clues. J. Ultrasound Med. 1993;12:323–330.
  25. Lynch S. A., Wright C.  Sirenomelia, limb reduction defects, cardiovascular malformation, renal agenesis in an infant born to a diabetic mother. Clin.Dysmorphol. 1997;6:75–80.
  26. Assimakopoulos E., Athanasiadis A., Zafrakas M., Dragoumis K., Bontis J. (2004). Caudal regression syndrome and sirenomelia in only one twin in two diabetic pregnancies. Clin. Exp. Obstet. Gynecol. 2004;31:151–153.
  27. Castori M., Silvestri E., Cappellacci S., Binni F., Sforzolini G. S., Grammatico P. (2010).Sirenomelia and VACTERL association in the offspring of a woman with diabetes. Am. J. Med. Genet. 2010;152A:1803–1807.
  28. Duncan P. A., Shapiro L. R. Interrelationships of the hemifacialmicrosomia-VATER, VATER, and sirenomelia phenotypes. Am. J. Med. Genet. 1993;47:75–84.
  29. Ferm V. H., Carpenter S. J. The relationship of cadmium and zinc in experimental mammalian teratogenesis. Lab. Invest. 1986;18:429–432.
  30. Hilbelink D. R., Kaplan S. Sirenomelia: analysis in the cadmium- and lead-treated golden hamster. Teratog.Carcinog.Mutagen. 1986;6:431–440.
  31. Castilla E. E., Mastroiacovo P., Lopez-Camelo J. S., Saldarriaga W., Isaza C., Orioli I.M. Sirenomelia and cyclopia cluster in Cali, Colombia. Am. J. Med. Genet. 2008;146A:2626–2636.
  32. Orioli I. M., Mastroiacovo P., Lopez-Camelo J. S., Saldarriaga W., Isaza C., Aiello H., Zarante I., Castilla E. E. Clusters of sirenomelia in South America. Birth Defects Res. A Clin. Mol. Teratol. 2009;85:112–118.
  33. Nievelstein et al. MR of the caudal Regression syndrome: Embryologic Implications.  AJNR 1994;15:1021-1029.


Parimala Sirikonda, Nalluri Himabindu. SIRENOMELIA: A DETAILED FETAL AUTOPSY STUDY. Int J Anat Res 2015;3(4):1669-1674. DOI: 10.16965/ijar.2015.311




Volume 1 (2013)

Volume 2 (2014)

Volume 3 (2015)

Submit Manuscript