E72.4 Disorders of ornithine metabolism

Billable ICD-10-CM code, FY2026. Acts as a Complication or Comorbidity (CC) as a secondary diagnosis.

Applicable to

• Hyperammonemia-Hyperornithinemia-Homocitrullinemia syndrome
• Ornithinemia (types I, II)
• Ornithine transcarbamylase deficiency

Excludes1 (never code together)

• hereditary choroidal dystrophy (H31.2-)

Applies from E72 Other disorders of amino-acid metabolism

Excludes1 (never code together)

• disorders of:
• aromatic amino-acid metabolism (E70.-)
• branched-chain amino-acid metabolism (E71.0-E71.2)
• fatty-acid metabolism (E71.3)
• purine and pyrimidine metabolism (E79.-)
• gout (M1A.-, M10.-)

Risk adjustment (HCC)

• CMS-HCC V22: HCC 23 — Other Significant Endocrine and Metabolic Disorders
• RxHCC V08: HCC 43 — Pituitary, Adrenal Gland, and Other Endocrine and Metabolic Disorders
• ESRD V24: HCC 23

MS-DRG index

Defines the logic of DRG(s) 642 in MDC 10.

Approximate ICD-9-CM (GEMs)

• 270.6 Disorders of urea cycle metabolism (approximate)

Code annotations containing back-references to E72.4

Back-references to E72.4

• Type 1 Excludes: E72.2 Disorders of urea cycle metabolism ("disorders of ornithine metabolism (E72.4)")
• Type 1 Excludes: E72.20 Disorder of urea cycle metabolism, unspecified ("hyperammonemia-hyperornithinemia-homocitrullinemia syndrome E72.4")
• Type 2 Excludes: H31.2 Hereditary choroidal dystrophy ("hyperornithinemia (E72.4)")
• Type 2 Excludes: H31.2 Hereditary choroidal dystrophy ("ornithinemia (E72.4)")

Back-references to E72

• Type 2 Excludes: G11 Hereditary ataxia ("metabolic disorders (E70-E88)")
• Code First: G63 Polyneuropathy in diseases classified elsewhere ("metabolic diseases (E70-E88)")
• Type 2 Excludes: G71 Primary disorders of muscles ("metabolic disorders (E70-E88)")
• Code First: H42 Glaucoma in diseases classified elsewhere ("specified metabolic disorder (E70-E88)")
• Type 2 Excludes: N25.0 Renal osteodystrophy ("metabolic disorders classifiable to E70-E88")
• Type 2 Excludes: N25.81 Secondary hyperparathyroidism of renal origin ("metabolic disorders classifiable to E70-E88")
• Type 1 Excludes: P59 Neonatal jaundice from other and unspecified causes ("jaundice due to inborn errors of metabolism (E70-E88)")
• Type 1 Excludes: R79 Other abnormal findings of blood chemistry ("specific findings indicating disorder of amino-acid metabolism (E70-E72)")
• Type 1 Excludes: R79.83 Abnormal findings of blood amino-acid level ("disorders of amino-acid metabolism (E70-E72)")

Diagnosis Index entries for E72.4

• Deficiency, deficient › ornithine transcarbamylase
• Disorder (of) › metabolism NOS › amino-acid › ornithine
• Disorder (of) › metabolism NOS › ornithine
• Disorder (of) › ornithine metabolism
• Disorder (of) › urea cycle metabolism › ornithine transcarbamylase deficiency
• Disturbance (s) › metabolism › ornithine
• Hyperaminoaciduria › ornithine
• Hyperornithinemia
• Ornithine metabolism disorder
• Ornithinemia (Type I) (Type II)
• Syndrome › hyperammonemia-hyperornithinemia-homocitrullinemia

Nearby codes

• E72.21 Argininemia
• E72.22 Arginosuccinic aciduria
• E72.23 Citrullinemia
• E72.29 Other disorders of urea cycle metabolism
• E72.3 Disorders of lysine and hydroxylysine metabolism
• E72.4 Disorders of ornithine metabolism (this code)
• E72.5 Disorders of glycine metabolism
• E72.50 Disorder of glycine metabolism, unspecified
• E72.51 Non-ketotic hyperglycinemia
• E72.52 Trimethylaminuria
• E72.53 Primary hyperoxaluria