Primary hyperoxaluria, type 1

This code represents a rare, inherited metabolic disorder characterized by the overproduction of oxalate, primarily due to a deficiency in the liver enzyme alanine-glyoxylate aminotransferase (AGT). This leads to excessive oxalate accumulation in the kidneys and other organs, causing recurrent kidney stones, nephrocalcinosis, and progressive kidney failure.

Use this code when documentation confirms a diagnosis of Primary Hyperoxaluria Type 1, typically through genetic testing or enzyme assay. This diagnosis is often suspected in patients with early-onset, recurrent calcium oxalate kidney stones, nephrocalcinosis, or unexplained kidney failure.

• Ensure documentation specifies "Type 1" as there are other types of primary hyperoxaluria.
• Code any associated complications, such as chronic kidney disease (N18.-) or nephrolithiasis (N20.0), as secondary diagnoses.
• Do not confuse with secondary hyperoxaluria, which is acquired and due to other causes like dietary factors or malabsorption.