Other disturbances of aromatic amino-acid metabolism

This code represents a group of rare inherited metabolic disorders affecting the body's ability to properly break down or synthesize aromatic amino acids, such as phenylalanine, tyrosine, and tryptophan. These disturbances can lead to an accumulation of toxic byproducts or deficiencies of essential compounds, impacting various organ systems.

Use this code for documented diagnoses of metabolic disorders involving aromatic amino acids that are not specifically classified elsewhere (e.g., phenylketonuria, tyrosinemia, alkaptonuria). This includes conditions like histidinemia, hyperphenylalaninemia (unspecified), or other unlisted defects in aromatic amino acid pathways. Documentation should clearly state the specific aromatic amino acid affected and the nature of the metabolic disturbance.

• Do not use this code if a more specific ICD-9-CM code exists for the aromatic amino acid disorder (e.g., 270.0 for PKU).
• Ensure the physician's documentation explicitly states "other" or "unspecified" disturbances of aromatic amino acid metabolism if a definitive diagnosis is not yet established.
• Consider sequencing this code as a primary diagnosis when it is the reason for the encounter, or as a secondary diagnosis when it is a co-morbidity.