Active clinical trials for "Urea Cycle Disorders, Inborn"

This project will examine the dysregulation of the urea cycle in patients with terminal uremia using a validated method named "Functional Hepatic Nitrogen Clearance"

Urea cycle disorders (UCDs) are dramatic congenital inherited metabolic disorders. There is no cure. Many novel therapeutic approaches are currently being developed, which hopefully will change the current situation. Testing the efficacy of such new therapies in patients is a challenge, because many clinical parameters are influenced by several disturbances and biochemical parameters are often not very specific. The measurement of ureagenesis is a tool to analyze the entire function of the urea cycle in a single test. This is more meaningful for the characterization of UCD patients than the analysis of single metabolites or enzymes. Therefore, the test will be important to evaluate current and future novel therapies. The term "ureagenesis" means "production of urea", which is the main task of the urea cycle. This total urea production can be measured with a "tracer" (in this case a stable ammonium chloride isotope). This tracer is non-radioactive and non-toxic. It is for example used as an unmarked substance in cough syrup, diuretic drugs and as food additive. Thus, the tracer does not pose a risk to the participant, especially since only a very low dose is applied. The investigators will analyze specific substances from the urea cycle (namely [15N, 14N] urea and several [15N] amino acids) that are produced during the test and compare them with results from healthy people. The maximum test duration is 5 hours. This project is being carried out at one site, namely the University Children's Hospital in Zurich. This project is being carried out under Swiss law. The responsible Ethics Committee has reviewed and approved the study.

In proximal urea cycle disorders (UCD), particularly ornithine transcarbamylase deficiency (OTCD), hyperammonemia (HA) causes increased brain glutamine (Gln) which perturbation is thought to be at the core of the neurological injury. In contrast, in distal UCD such as citrullinemia (argininosuccinate synthetase deficiency; (ASSD) and argininosuccinic aciduria (argininosuccinate lyase deficiency); (ASLD) cognitive impairment and neuropsychiatric disease are common even in the absence of acute HA. As a consequence, both citrulline and argininosuccinate (ASA) or their metabolic products have been implicated as neurotoxic. In this project the investigators will use state-of- the-art neuroimaging and neuropsychological methods to investigate whether patients with OTCD have chronically elevated brain Gln and reduced myo-inositol (mI) levels that correlate with regional brain structural abnormalities and neurocognitive dysfunction. The researchers will further investigate whether during an acute episode of HA elevated brain Gln and decreased mI levels correlate with the magnitude of cytotoxic edema and whether a Gln/mI ratio threshold can be identified at which the cytotoxic edema is followed by cell loss. Finally, the researchers will investigate whether regions of brain damage in ASSD and/or ASLD are distinct from those in OTCD and compare brain Gln levels in ASSD and ASLD in the absence of HA to those in OTCD. The investigators will also seek to determine if brain citrulline and ASA can be identified in the brains of patients with distal UCD and whether they correlate with brain abnormalities seen in MRI and neuropsychological testing. This project will elucidate the chronology of brain pathology both in acute hyperammonemia and chronic UCD and whether, proximal and distal UCD differ in their pathophysiology of brain damage.

Urea cycle disorders (UCD) are a group of rare inherited metabolism disorders. Infants and children with UCD commonly experience episodes of vomiting, lethargy, and coma. The purpose of this study is to perform a long-term analysis of a large group of individuals with various UCDs. The study will focus on the natural history, disease progression, treatment, and outcome of individuals with UCD.

Ammonia is a waste product of protein and amino acid catabolism and is also a potent neurotoxin. High blood ammonia levels on the brain can manifest as cytotoxic brain edema and vascular compromise leading to intellectual and developmental disabilities. The following aims are proposed: Aim 1 of this study will be to determine the chronology of biomarkers of brain injury in response to a hyperammonemic (HA) brain insult in patients with an inherited hyperammonemic disorder. Aim 2 will be to determine if S100B, NSE, and UCHL1 are altered in patients with two other inborn errors of metabolism, Maple Syrup Urine Disease (MSUD) and Glutaric Acidemia (GA1).

All patients having received at least one infusion of the Investigational Medicinal Product (IMP) HepaStem HHALPC during a previous interventional clinical study conducted by Promethera Biosciences

This is a multi-center, cross-sectional study to assess risk for liver fibrosis and hepatic injury in individuals with urea cycle disorders (UCDs) using serum biomarkers, Fibroscan, and MRE. This study will be conducted at 5 sites of the Urea Cycle Disorders Consortium: Baylor College of Medicine in Houston, TX, Seattle Children's Hospital in Seattle, WA, Children's Hospital Colorado in Aurora, CO, Children's Hospital of Philadelphia in Philadelphia, PA, and Children's National Medical Center in Washington D.C.

This is a multi-site, retrospective chart review as well as a prospective study to evaluate histopathologic findings in liver samples from individuals with any UCD diagnosis. This study will be conducted at all Urea Cycle Disorders Consortium (UCDC) sites: Baylor College of Medicine in Houston, TX and Children's National Medical Center in Washington D.C.

Study around children with inborn errors of metabolism (IEM) and their healthy siblings. Collection of stool and urine to assess contribution of microbiota to disease severity.

The objective is to determine if acetohydroxamic acid (AHA) can prevent hydrolysis of urea by inhibiting the bacterial urease of gut flora of both healthy control adults as well as adults with urea cycle disorders