The congenital malformation of the renal system results in fused kidneys.Twice as common in males.The fusion of the lower poles of the kidneys results trapping of the fused kidneys under the inferior mesenteric artery. It is the arrest of the normal retroperitoneal ascent of the kidneys. Associated with Turner syndrome, trisomy 18 (Edwards syndrome). Most commonly asymptomatic, other symptoms include increased rate of urinary tract infections, hydronephrosis due to ureteropelvic junction obstruction, renal stones On the physical exam there is abdominal fullness upon palpation.