Hi, Thanks for writing in. It is possible that your grandson has got duplicated renal collecting system on one side and this is being referred to as bicornuate kidney. Duplex collecting systems are seen in 0.7% of the normal adult population and in 2-4% of patients investigated for urinary tract symptoms. Here one kidney has two tubes connecting the kidney and urinary bladder. This results in one of the tubes forming an ureterocele at the lower end in the bladder. This cai=uses problems in voiding the bladder. Surgical treatment id done depending on the nature of the abnormality. Treatment of the ureterocele often depends on the size of the constriction and how well the kidney that the ureter drains is functioning.