Renal hypoplasia may be caused by multiple genetic mutations (e.g., HFN1B, PAX2, PXB1) as well as environmental factors such as intrauterine growth restriction (IUGR), maternal diabetes, hypertension, anti-inflammatory or antihypertensive drug use during pregnancy, or maternal alcohol and tobacco consumption [31,32]. The gene discussed is PAX2; the disease is renal hypoplasia.