Unilateral renal hypoplasia and aplasia have both been reported in individuals with ring 18.

Mutations within PAX2 have been shown to result in optic nerve colobomas and renal hypoplasia.

There is a small association between Gartner's duct cysts and metanephric urinary anomalies, such as ectopic ureter & ipsilateral renal hypoplasia.

In fetuses, visceral anomalies consisted of dilated brain ventricles, dilated nares, olfactory bulb, renal hypoplasia, and other abnormalities.

Papillorenal syndrome, also called Renal-coloboma syndrome or isolated renal hypoplasia, is an autosomal dominant genetic disorder marked by underdevelopment (hypoplasia) of the kidney and colobomas of the optic nerve.

It can be caused by renal diseases such as bilateral renal agenesis (BRA), atresia of the ureter or urethra causing obstruction of the urinary tract, polycystic or multicystic kidney diseases, renal hypoplasia, amniotic rupture, uteroplacental insufficiency from maternal hypertension or toxemia.