The Sirenomelia Sequence: A Case History

Abstract

We report a case of sirenomelia sequence observed in an incident of preterm labor during the 29th gestational week. According to some authors, this syndrome should be classified separately from caudal regression syndrome and is likely to be the result of an abnormality taking place during the fourth gestational week, causing developmental abnormalities in the lower extremities, pelvis, genitalia, urinary tract and digestive organs. Despite recent progress in pathology, the etiopathogenesis of sirenomelia is still debated.

Sirenomelia with Oesophageal Atresia: A Rare Association

“…The causes of sirenomelia are not very clear, but the abnormalities point to an insult which occurs at fourth week of gestation [5]. Abnormally formed umbilical cord blood vessels have been implicated.…”

“…Though few survivors of this condition have been reported, such children rarely survive beyond the neonatal period [4]. The risk factors for sirenomelia include maternal diabetes, teratogens, genetic factors and maternal age which is less than 20 years [5].…”

“…The vitelline umbilical artery steals blood and nutrition from the lower body and diverts it to the placenta. This results in a small aorta and variable absence of the arteries that supply the kidneys, large intestine, and genitalia, resulting in maldevelopment of terminal bowel, kidneys, bladder, genital organs and pelvic bones [2,5]. Reports on sirenomelia with normal umbilical arteries point to the alternative caudal dysgenesis (CD) theory [5].…”

“…However, no such correlation was found in our case. Controversy exists in the literature regarding as to whether sirenomelia occurs as a separate entity or as the extreme form of caudal regression syndrome (CRS) [1,5]. However, the presence of two umbilical arteries, non-lethal renal anomalies, non-fused lower limbs, abdominal wall defects and abnormalities of tracheoesophageal tree, neural tube and heart, differentiates CRS from sirenomelia [1].…”

Sirenomelia: A Case Report

“…Caudal regression syndrome is characterised by developmental abnormalities of the lower limbs and sacrum associated with spinal cord abnormalities and urinary incontinence. In caudal regression syndrome, two umbilical arteries instead of one are found and fused lower limbs, renal agenesis and imperforate anus are rare [11,12]. VACTERL syndrome is characterised by vertebral anomalies, anal atresia, cardiac defects, tracheoesophageal fistula, renal and radial anomalies and limb defects.…”