Urea cycle disorders are caused by enzyme or transporter defects in the Urea cycle (WP4571). These diseases are characterised by hyperammonemia, respiratory alkalosis and encephalopathy and the severity of the disease depends on the severity of the defect and the place of the defect in the cycle. Severe forms usually have an onset in infancy, while mild forms can also present in adulthood.
The diagnosis of Urea cycle disorders is based on altered concentrations of different metabolic biochemical markers. Some of these markers are metabolites in the Urea cycle, but there are also several other markers, that are either indirectly or not related to the Urea cycle. All metabolic markers used for the diagnosis of at least one Urea cycle disorder and their relations are visualized in this pathway.
Biochemical markers derived from http://www.iembase.org/, for all diseases pictured in WP4571