2026 ICD-10-CM Diagnosis Code E72.4Disorders of ornithine metabolism

ICD-10-CM Codes›E00–E89›E70-E88›E72

ICD-10-CM E72.4
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

E72.4 is a billable ICD-10-CM diagnosis code for disorders of ornithine metabolism. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). Coders also document this condition as disorder of ornithine metabolism. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified and unspecified nutritional and metabolic disorders.

Code Identity

ICD-10-CM Code
E72.4
Billable Status
Yes — Valid for Submission
Code Describes
Disorders of ornithine metabolism
Short Description
Disorders of ornithine metabolism
Same as the full description in the CMS dataset.
Parent Code
E72
Other disorders of amino-acid metabolism

Code Classification

ChapterE00–E89Endocrine, nutritional and metabolic diseases
SectionE70-E88Metabolic disorders
CategoryE72Other disorders of amino-acid metabolism
This CodeE72.4Disorders of ornithine metabolism

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Disorder of ornithine metabolism
  • Hyperammonemia
  • Hyperornithinemia
  • Hyperornithinemia-hyperammonemia-homocitrullinuria syndrome
  • Ornithine aminotransferase deficiency
  • Ornithine carbamoyltransferase deficiency

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

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

Type 1 Excludes

  • hereditary choroidal dystrophy H31.2

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • 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

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR END016
Other specified and unspecified nutritional and metabolic disorders
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Carbamoyl-Phosphate Synthase I Deficiency Disease

    a urea cycle disorder manifesting in infancy as lethargy, emesis, seizures, alterations of muscle tone, abnormal eye movements, and an elevation of serum ammonia. the disorder is caused by a reduction in the activity of hepatic mitochondrial carbamoyl-phosphate synthase (ammonia). (menkes, textbook of child neurology, 5th ed, pp50-1)

  • Hyperammonemia

    elevated level of ammonia in the blood. it is a sign of defective catabolism of amino acids or ammonia to urea.

  • Hyperlysinemias

    a group of inherited metabolic disorders which have in common elevations of serum lysine levels. enzyme deficiencies of alpha-aminoadipic semialdehyde dehydrogenase and the saccharopine dehydrogenases have been associated with hyperlysinemia. clinical manifestations include mental retardation, recurrent emesis, hypotonia, lethargy, diarrhea, and developmental delay. (from menkes, textbook of child neurology, 5th ed, p56)

  • Rett Syndrome

    an inherited neurological developmental disorder that is associated with x-linked inheritance and may be lethal in utero to hemizygous males. the affected female is normal until the age of 6-25 months when progressive loss of voluntary control of hand movements and communication skills; ataxia; seizures; autistic behavior; intermittent hyperventilation; and hyperammonemia appear. (from menkes, textbook of child neurology, 5th ed, p199)

Patient EducationClinical

Amino Acid Metabolism Disorders

Metabolism is the process your body uses to make energy from the food you eat. Food is made up of proteins, carbohydrates, and fats. Your digestive system breaks the food parts down into sugars and acids, your body's fuel. Your body can use this fuel right away, or it can store the energy in your body.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert E72.4 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
270.6 Dis urea cycle metabol
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About E72.4Overview

Is E72.4 (Other disorders of amino-acid metabolism) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report disorders of ornithine metabolism on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What is the ICD-9 equivalent of E72.4?

Under the General Equivalence Mappings, disorders of ornithine metabolism converts to ICD-9-CM 270.6 (dis urea cycle metabol). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.