Kidney Disease Biomarkers

Study Summary

Kidney Disease Biomarkers Summary: This study will identify biomarkers (proteins and other molecules in the blood or urine) that may help scientists predict what kidney disease a patient has and whether a given patient would respond to particular therapies. The study will look for biomarkers in the blood and urine of patients with various kidney diseases and study of the effects of angiotensin converting enzyme inhibitors (ACE inhibitors) and angiotensin receptor blockers (ARB) on biomarkers. Blood and urine from healthy volunteers will be studied for comparison. Healthy people and the following patients may be eligible for this study: adults with diabetic nephropathy 18 years of age and older; children with newly diagnosed clinical idiopathic nephrotic syndrome between 2 and 18 year of age; children and adults with glomerular disease (minimal change disease, focal segmental glomerulosclerosis, or collapsing glomerulopathy). Participants undergo tests and procedures as follows: Glomerular Disease: Adults with glomerular disease provide about four to six blood and urine samples over the course of 6 to 12 months. The samples are collected at the time of regularly scheduled visits for the NIH treatment protocol in which they are participating. Children provide only blood samples. Chronic Kidney Disease: Patients with chronic kidney disease provide a blood and urine sample every 6 months for 3 years or more. Angiotensin Antagonism: Patients with chronic kidney disease who are taking ACE inhibitors or ARBs stop their medicines for 4 weeks, while those who are not taking ACE inhibitors or ARBs begin one of the medicines. In general, patients just starting on the medications continue them after the study is completed, since they are beneficial for chronic kidney disease. * Medication withdrawal group: Patients come to NIH for 2 successive days at the beginning of the study for blood and urine tests (including one 24-hour urine collection) and to receive iothalamate