Clinical Research Directory

Liver Metabolic Functions in Patients With Citrin Deficiency and Healthy Subjects

Citrin is an aspartate-glutamate transporter in the liver that facilitates the urea cycle pathway for ammonia detoxification via ureagenesis. It is also thought to be involved in liver energy metabolism as a component of the malate-aspartate shuttle. The clinical presentation in patients supports the hypothesis that liver glycolytic, gluconeogenic and lipogenic functions are compromised in citrin deficiency, but none of the key hepatic pathway fluxes have been measured in patients to date. This is the first study that will examine the liver metabolic fluxes in patients with citrin deficiency. Liver metabolic functions will be examined by metabolic flux assays and biochemical measurements after application of stable isotopes 2H2O and \[U-13C6\]-fructose. Urea cycle metabolites and their enrichment after application of a stable isotope tracer 15NH4Cl will be measured to examine the liver's ability to detoxify ammonia into urea.

Multi-omics Study in Citrin Deficiency

Citrin deficiency (CD) is an underdiagnosed and understudied condition characterized by several distinct phenotypes: 1) neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD), 2) the adaptation or silent period, 3) "failure to thrive and dyslipidemia" form of CD (FTTDCD), and 4) citrullinemia type II (CTLN2), with the latter representing the final and most severe form of the condition. There is currently no cure for CD and patients manage their symptoms with lifelong dietary intervention and regular checkups with their physicians. A major hurdle in developing effective treatments for CD is the lack of effective biomarkers that track well with disease severity or measure the effectiveness of therapeutics. The present study aims to identify robust circulating biomarkers of CD through analysis of blood samples from CD patients.