Recent evidence from epidemiological studies suggests that serum uric acid levels higher than average predispose diabetic patients to kidney damage. The purpose of this study is to gather preliminary information on whether lowering serum uric acid by means of oral allopurinol (a drug commonly used for the treatment of gout) can be used to prevent or delay the loss of kidney function that may accompany diabetes. The results of this study will help us design a larger study to find out whether this medication can prevent kidney problems, in particular the loss of kidney function, in people with type 1 diabetes.