Enteric Oxalate Absorption Study in Unclassified Hyperoxaluria

Investigations Into the Genotype and Phenotype of Unclassified Hyperoxaluria: Enteric Oxalate Absorption Study

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.

Inclusion Criteria:

• Age equal to or greater than 4 years (patient must be able to void on request).
• Have good health.

Exclusion Criteria:

• 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 the study.
• Subjects with GFR < 50 cc/min will be excluded.