Deterioration of renal function in a conjoined twin: lack of compensatory renal hypertrophy.

The renal function of conjoined twin girls was evaluated by radioisotopic, radiographic, and laboratory techniques. The smaller of the twins was shown to have severe impairment of renal function, but due to the "auto-dialysis" by her normal twin, she was able to maintain a normal BUN and creatinine. Compensatory hypertrophy was not found in the normal twin, despite renal failure and loss of renal mass in the smaller twin.