The purpose of this study is to learn more about a condition called 'unclassified
hyperoxaluria'. People with this condition have large amounts of oxalate in their urine,
which can cause kidney stones and kidney failure. We do not know what causes the high level
of oxalate in the urine. In this study, we will evaluate absorption of a test dose of
oxalate taken orally by measuring the amount of the test dose that is eliminated in the
urine. We will compare the results of affected patients to healthy volunteers.
Participants' oxalate intake and output will be monitored and assessed over a 24 hour
period. Participants will ingest a prescribed oxalate dose and urine oxalate will be
monitored for the 24 hour study period.
- Age equal to or greater than 4 years (patient must be able to void on request).
- Have good health.
- Any prior history of renal disease, or hypertension
- ALL subjects (controls and affected patients) will be asked to discontinue any
diuretics, calcium supplements, H2 blockers, proton pump inhibitors or
gastrointestinal motility agents for approximately one week prior to initiation of
- Subjects with GFR < 50 cc/min will be excluded.