L-Homocitrulline is an amino acid and can be detected in larger amounts in the urine of individuals with urea cycle disorders.

At present, it is thought that the depletion of the ornithine supply causes the accumulation of carbamyl-phosphate in the urea cycle which may be responsible for the enhanced synthesis of homocitrulline and homoarginine.

Carbamylation of nucleophilic amino groups, for example lysine residues, can modify protein structures and ultimately cause metabolic dysfunctions.

In people with hyperammonemia orotic acid and homocitrulline appear to be chronically elevated after a high protein diet, but may be normal when fasting.

Since in this disorder the human body cannot effectively break down these amino acids people typically experience nausea and vomiting after ingesting protein rich foods.

Associated features of this protein intolerance may include an enlarged liver and spleen, short stature, muscle weakness, impaired immune function, and progressively brittle bones that are prone to fracture and a lung disorder called pulmonary alveolar proteinosis may also develop.