Among genitourinary anomalies associated with congenital vertebral anomalies, which is the most common?

• A. Bilateral hydronephrosis
• B. Hypospadias
• C. Unilateral renal agenesis
• D. Polycystic kidney disease

Answer: (D)

Genitourinary anomalies often accompany congenital vertebral anomalies because kidney development and spine formation occur around the same time from mesodermal tissue. The most common GU finding in this setting is unilateral renal agenesis, where one kidney is absent. This pattern fits with embryologic disruption affecting the urogenital ridge and nearby structures that can produce both vertebral defects and a missing kidney on one side.

Polycystic kidney disease, while a renal disorder, is a bilateral, inherited condition and does not typically arise as the most frequent coexisting GU anomaly with vertebral malformations. Hydronephrosis and other renal anomalies can occur, but unilateral renal agenesis remains the most commonly observed association.

In practice, if a vertebral anomaly is identified, it’s prudent to screen for renal agenesis or dysplasia with imaging, since renal involvement is the most frequent co-occurring GU finding.