Bilateral Renal Agenesis
Bilateral renal agenesis is a uniformly lethal anomaly. Absence of the kidneys causes anhydramnios, resulting in pulmonary hypoplasia, characteristic facies, and positional extremity abnormalities.
It is often challenging to diagnose absence of a structure, and bilateral renal agenesis can be particularly challenging because the lack of amniotic fluid impairs visualization.
Renal agenesis results when the ureteric bud either fails to develop from the mesonephric duct or fails to induce the surrounding metanephric mesenchyme. There is usually absence of the seminal vesicles and vas deferens in males, and a high incidence of müllerian anomalies and müllerian agenesis in females.