Extreme caudal agenesis. Possible drug-related etiology?

Background: Caudal regression syndrome (CRS) is a rare anomaly of the lower body pole that represents a continuum of congenital malformations ranging from isolated sacral agenesis to absence of the lumbosacral spine and major visceral anomalies. While the exact etiology of this syndrome is unclear, maternal diabetes, genetic factors, teratogens and vascular anomalies altering blood flow have been hypothesized to play a role in its pathogenesis.

Case: A fetus had extreme hypotrophy of the caudal body pole, aplasia of the lower spine and complete renal agenesis diagnosed in the second trimester by ultrasound. Maternal history revealed the use of minoxidil solution for preventing hair loss for four years prior to and during gestation. Also, the mother had taken trimethoprim-sulfamethoxazole during the first trimester for treatment of upper respiratory disease. No maternal diabetes or history of familial genetic diseases was evident.

Conclusion: In an extreme form of CRS consisting of complete aplasia of the lower body pole and viscera and additional malformations, a possible drug-related etiology was suggested but should be confirmed by more studies.