Although urinary tract differences are rare, the most common ones are:

Hydronephrosis (pronounced ‘hi-dron-eff-roe-sis’):
This condition is where one or both kidneys swell up due to the build up of urine. This happens if urine is unable to flow from the kidney (or both kidneys) to the bladder and is sometimes caused by a blockage or a urinary infection.
Ureteral duplication (pronounced ‘yur-eet-eral dew-plik-ay-shun’), also called duplex kidney:
This is where one or both kidneys have an extra ureter tube connecting down to the bladder, rather than one ureter connecting the kidney to the bladder.
Follow this link to read more about ureteral duplication.
Ureterocele (pronounced ‘yur-reet-ero-seel’):
This is where the lower part of the ureter becomes enlarged and forms a balloon-like structure inside the bladder.
Follow this link to read more about ureterocele.
Ectopic ureter (pronounced ‘ek-top-ik yur-eet-er’):
This describes a condition where the upper part of the ureter attaches incorrectly elsewhere in the urinary tract or bladder.
Follow this link to read more about ectopic ureter.
Vesicoureteral reflux (pronounced ‘vessy-co-yur-eet-er-ral ree-flux’), also called VUR:
VUR happens when urine flows backward from the bladder, back up into one or both ureters, and sometimes even into the kidney.
Follow this link to read more about vesicoureteral reflux.