Sirenomelia, which is also known as mermaid syndrome, is an extremely rare congenital developmental disorder characterized by anomalies of the lower spine and the lower limbs. Affected infants are born with partial or complete fusion of the legs. Treatment for a baby with mermaid syndrome usually involves seeing multiple medical specialists. The specialties depend on the syndrome's effects. Orthopedic surgeons have performed procedures to separate fused limbs. However, even with treatment, mermaid syndrome is typically fatal past the newborn period.