Also known as “Mermaid Syndrome” and sirenomelia sequence. If you want to cringe and feel a little beetle crawl in your stomach, click this link and then this one and then… if you thought those were gross click here. There you’ll see images of infants born with this very rare disorder. The single lower limb is connected or fused together in such a way they appear to be the fins of a mermaid. “The eyes are amphibian-like and the ears are floppy and low.” (Onigami) 1/100,000 babies born have this lethal malformation, and almost all die within a day or two after birth “because of complications associated with abnormal kidney and bladder development and function. It results from a failure of normal vascular supply from the lower aorta in utero. Sirenomelia is associated with maternal diabetes.” (Wikipeida) Only two people of a handful who have survived with the disorder have had corrective surgery, Tiffany Yorks of the United States and Milagros Cerrón of Peru.

Medical definition:

Congenital anomaly, caused by a disruptive vascular defect, characterized by fusion of the lower extremities, associated with renal agenesis, absence of the sacrum, rectum, and bladder. It was considered in the past to represent a severe form of caudal regression syndrome.” (The Fetus)

    Typical-important facts:
  • Not hereditary (sporadic)
  • Considered lethal within 48 hours
    • Only a handful of survivors
  • Rotation of legs is not possible with fusion of legs (often only one femur).
    • Legs remain in fetal position
  • ”The fibulae when present are between the tibia and the sole of the foot is oriented ‘ventrally’ instead of ‘dorsally.’” (The Fetus)
  • 300 cases have been reported world wide with a 3:1 male-female ratio. (Ijri)
  • Typical absence of genitalia (except for gonads).
  • Imperforate anus.

Proposed causes:
“Three pathogenic theories have been proposed to explain this malformation, including: 1) a pressure theory, 2) primary failure in the development of caudal somities that leads to defective development of the lower parts of the embryo, and 3) a lack of nutritional support to the caudal region of the body’s embryo.” (The Fetus2) Nothing conclusive has been found from any of these theories. In fact that article said, “The precise etiology of sirenomelia is not well understood.”

If you are diagnosed with Sirenomelia it is suggested you consider terminating your pregnancy for your own health.

Sandra R Silva, MD & Philippe Jeanty, MD, PhD, Sirenomelia, (1999), accessed 10/26/06
Danilo Dordoni, MD*, Patricia C. Freeman, RT, RDMS, (1991), accessed 10/26/06
Website with illustration and brief description, 10/26/06
Wikipedia. (2006) 10/26/06|Wikipeida