Particularities of a Fetus with Sirenomelia and Conceptual Separation from Caudal Regression Syndrome

Abstract Sirenomelia is a very rare congenital anomaly, defined by partial or complete fusion of the lower limbs. Additional malformations may also occur, the phenotype being variable. Over time, sirenomelia has been considered the last stage of the evolution of caudal regression syndrome. However, the different characteristics in the context of the two syndromes, such as the single umbilical artery or, less often, two vessels, renal agenesis and the imperforate anus characteristic of sirenomelia as opposed to caudal regression syndrome where all three umbilical vessels are identified, along with sacral agenesis, led to the separation of the two entities. Sirenomelia is a multifactorial disease, with genetic heterogeneity, most cases being sporadic. Its pathogenesis is incompletely deciphered. Thus, we present a case of sirenomelia, diagnosed after abortion at the end of the first trimester. The fetal autopsy gave us details of skeletal and visceral abnormalities. The sex of the aborted could not be determined due to the incomplete development of the genital tract. To our knowledge, this is the first case reported in Constanta County. We hope that this presentation will be useful in trying to understand the causes of this condition.