2026 ICD-10-CM Diagnosis Code G71.3Mitochondrial myopathy, not elsewhere classified

ICD-10-CM Codes›G00–G99›G70-G73›G71

ICD-10-CM G71.3
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

G71.3 is a billable ICD-10-CM diagnosis code for mitochondrial myopathy, not elsewhere classified. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Myopathies.

Code Identity

ICD-10-CM Code
G71.3
Billable Status
Yes — Valid for Submission
Code Describes
Mitochondrial myopathy, not elsewhere classified
Short Description
Mitochondrial myopathy, not elsewhere classified
Same as the full description in the CMS dataset.
Parent Code
G71
Primary disorders of muscles

Code Classification

ChapterG00–G99Diseases of the nervous system
SectionG70-G73Diseases of myoneural junction and muscle
CategoryG71Primary disorders of muscles
This CodeG71.3Mitochondrial myopathy, not elsewhere classified

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Adult-onset chronic progressive external ophthalmoplegia with mitochondrial myopathy
  • Adult-onset multiple mitochondrial deoxyribonucleic acid deletion syndrome due to deoxyguanosine kinase deficiency
  • Autosomal dominant mitochondrial myopathy with exercise intolerance
  • Childhood myocerebrohepatopathy spectrum
  • Combined oxidative phosphorylation defect type 39
  • Congenital cataract, hypertrophic cardiomyopathy, mitochondrial myopathy syndrome
  • Cytochrome-c oxidase deficiency
  • Diabetes mellitus associated with genetic syndrome
  • DNA2-related mitochondrial DNA deletion syndrome
  • FASTKD2-related infantile mitochondrial encephalomyopathy
  • FBXL4-related encephalomyopathic mitochondrial DNA depletion syndrome
  • Hereditary cerebellar atrophy
  • Hypertrophic mitochondrial cardiomyopathy
  • Lethal infantile mitochondrial myopathy
  • Maternally inherited mitochondrial cardiomyopathy
  • Maternally inherited mitochondrial cardiomyopathy and myopathy
  • Maternally inherited mitochondrial myopathy
  • Mitochondrial deoxyribonucleic acid depletion syndrome myopathic form
  • Mitochondrial DNA depletion syndrome encephalomyopathic form
  • Mitochondrial DNA depletion syndrome encephalomyopathic form with methylmalonic aciduria
  • Mitochondrial DNA depletion syndrome, encephalomyopathic form with variable craniofacial anomalies
  • Mitochondrial encephalomyopathy
  • Mitochondrial myopathy
  • Mitochondrial myopathy with reversible cytochrome C oxidase deficiency
  • Mitochondrial myopathy with sideroblastic anemia syndrome
  • Mitochondrial myopathy, cerebellar ataxia, pigmentary retinopathy syndrome
  • Mitochondrial myopathy, lactic acidosis, deafness syndrome
  • Mitochondrial neurogastrointestinal encephalomyopathy syndrome
  • Myopathy and diabetes mellitus
  • Progressive external ophthalmoplegia, myopathy, emaciation syndrome
  • Pure mitochondrial myopathy
  • RRM2B-related mitochondrial DNA depletion syndrome, encephalomyopathic form with renal tubulopathy
  • Severe X-linked mitochondrial encephalomyopathy
  • TK2-related mitochondrial deoxyribonucleic acid depletion syndrome myopathic form
  • TMEM70 related mitochondrial encephalo-cardio-myopathy

Tabular List NotesGuidance

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

Type 1 Excludes

  • Kearns-Sayre syndrome H49.81
  • Leber's disease H47.21
  • Leigh's encephalopathy G31.82
  • mitochondrial metabolism disorders E88.4
  • Reye's syndrome G93.7

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.

    • Myopathy
      • mitochondrial NEC

Clinical ClassificationClinical

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

CCSR NVS018
Myopathies
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Mitochondrial Myopathy

    myopathy caused by mitochondrial abnormalities.

Patient EducationClinical

Mitochondrial Diseases

Metabolism is the process your body uses to make energy from the food you eat. Food is made up of proteins, carbohydrates, and fats. Chemicals in your digestive system (enzymes) break 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 tissues.

Read the full article at MedlinePlus

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

Convert G71.3 to ICD-9-CMHistory

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

ICD-9-CM
359.89 Myopathies NEC
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 G71.3Overview

Is G71.3 (Primary disorders of muscles) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report mitochondrial myopathy, not elsewhere classified on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What is the ICD-9 equivalent of G71.3?

Under the General Equivalence Mappings, mitochondrial myopathy, not elsewhere classified converts to ICD-9-CM 359.89 (myopathies NEC). 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.