Renal agenesis is a medical condition in which one (unilateral) or both (bilateral) fetal kidneys fail to develop. Renal agenesis is a medical condition in which one (unilateral) or both (bilateral) fetal kidneys fail to develop. Unilateral and bilateral renal agenesis in humans, mice and zebra fish has been linked to mutations in the gene GREB1L. It has also been associated with mutations in the genes RET or UPK3A. in humans and mice respectively. Bilateral renal agenesis is a condition in which both kidneys of a fetus fail to develop during gestation. It is one causative agent of Potter sequence. This absence of kidneys causes oligohydramnios, a deficiency of amniotic fluid in a pregnant woman, which can place extra pressure on the developing baby and cause further malformations. The condition is frequently, but not always the result of a genetic disorder, and is more common in infants born to one or more parents with a malformed or absent kidney.