Longitudinal Study of Urea Cycle Disorders

This study is looking for people who have been diagnosed with one of several specific urea cycle disorders. This diagnosis must be confirmed through certain tests, such as finding a specific genetic change (a 'pathogenic mutation'), or having low levels of particular enzymes in the liver which are important for processing ammonia. In some cases, high levels of ammonia in the blood, combined with a close family member also having a similar diagnosis, are also part of the criteria.

Specifically, the study is recruiting individuals with diagnoses of NAGS deficiency, CPS I deficiency, OTC deficiency, AS deficiency (Citrullinemia), AL deficiency (Argininosuccinic Aciduria, ASA), or ARG deficiency (Hyperargininemia). The diagnosis for each of these conditions has very specific medical requirements that your doctor would be able to check against your medical records.

If you have received a medical diagnosis of one of these conditions, and your doctor can confirm the specific details of your diagnosis match the study's requirements, then you might be eligible to take part.

If you join this study, your first visit will involve a detailed chat about your medical history and diet, as well as physical and neurological (nerve and brain) examinations. You'll also have some tests to look at your thinking skills and blood tests. After this first visit, you'll have follow-up appointments. These visits will typically last about 2-3 hours each.

How often you're seen depends on when your UCD symptoms first appeared. If your symptoms started when you were a baby, you'll have check-ups every 3 months until you're two years old, and then every 6 months after that. If your symptoms started later in life, you'll be seen every 6 months. Tests that look at your thinking skills will happen every 2 years and can take from 30 minutes for younger children up to 3 hours, depending on the types of tests given. This study is expected to continue until 2025.