<unk>  or Mermaid Syndrome is a very rare congenital deformity in which the legs are fused together, giving the appearance of a mermaid.  This condition is found in approximately one out of every 70,000 live births (about as rare as conjoined twins) and is usually fatal within a day or two of 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.<unk>  is associated with maternal diabetes.
There may be a connection to VACTERL association.
This disorder was formerly thought to be an extreme case of Caudal Regression Syndrome; however, it was reclassified to be considered a separate condition.
Sirenomelia
Phocomelia
Loxoscelism
Pseudo-Hurler polydystrophy
Thanatophoric dysplasia
Gnathodiaphyseal dysplasia
Psychogenic dwarfism
Uhl anomaly