MONDO_0019105 (renal nutcracker syndrome) is a rare, syndromic renal disease characterized by the entrapment of left renal vein (LRV) between the superior mesenteric artery (SMA) and the abdominal aorta, resulting in increased luminal pressure, renal hilar varices, hematuria and, at the microscopic level, rupture of thin-walled veins into the collecting system in renal fornices. Also known as: RNS, left renal vein entrapment syndrome.