Which of the following amino acids is most closely associated with the development of urea cycle disorders?

A Arginine
B Citrulline
C Ornithine
D Aspartate
Citrulline is a key intermediate in the urea cycle, and its accumulation is a hallmark of urea cycle disorders such as citrullinemia.
Scriver's The Metabolic and Molecular Bases of Inherited Disease
Metabolic and Nutritional Disorders Urea Cycle Disorders Biochemical Basis of Urea Cycle Disorders Hard MEDICAL Confidence: high