How do I learn more about current open studies?
Below you will find a list of current studies. Clicking on the link will take you to the study summary, which will provide you with all the important details for each study.


 How do I participate in a study?
Each study summary provides a list of hospitals or clinics where the study is being run. Using the contact information provided, you may contact any of these facilities in order to request participation in a study.


Current UCDC Studies

All Urea Cycle Disorders Studied by the UCDC:

Specific Disorders:

Arginase 1 Deficiency (ARG1D)

Argininosuccinate Synthase Deficiency (Citrullinemia I)

Argininosuccinate Lyase (ASL) Deficiency (Argininosuccinic Aciduria)

Carbamyl Phosphate Synthetase Deficiency (CPSD)

N-Acetylglutamate Synthase (NAGS) Deficiency

Ornithine Transcarbamylase (OTC) Deficiency

Past Studies (no longer accruing)

For All Urea Cycle Disorders Studied by the UCDC:

Argininosuccinate Lyase Deficiency (Argininosuccinic Aciduria)

Ornithine Transcarbamylase (OTC) Deficiency

Argininosuccinate Synthetase Deficiency (ASSD) (Citrullinemia I)


Please Note: The Rare Diseases Clinical Research Network will make every effort to enroll all the patients we can, but we cannot make any guarantees that we will be able to enroll everyone in a particular study who wants to participate.


Other urea cycle disorders research conducted outside of the UCDC, a service of the U.S. National Institues of Health, is a registry and results database of publicly and privately supported clinical studies of human participants conducted around the world.  Patients and families can use the website to search for clinical studies for a particular disorder or in a particular geographic region.  It can also be used to learn more about clinical studies.  Researchers use the site to register studies and to share results.  To find other clinical studies, type "urea cycle disorders" and/or your specific disorder (e.g. OTC, ornithine transcarbamylase deficiency, arginanse deficiency, etc.) in the "Search for Studies" field.