G71.21 ICD-10-CM Code: Nemaline myopathy

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for G71.21 in the official ICD-10-CM tabular list, quoted as published.

Source: CMS/CDC — ICD-10-CM Tabular ListRelease: FY2026Effective: October 1, 2025

Notes without a marker are published on G71.21 itself; “inherited from” names the category or block whose note applies here.

Coder workflow for G71.21

MedCoder structured workflow — derived from this code’s own official record

Documentation check

The provider’s diagnostic statement

Codes are assigned from the provider’s documented diagnosis, not from clinical criteria, test values or a medication list (Guidelines I.A.19).

Official instructions as workflow

• Excludes2 — not part of G71.21(3 notes)

  Coding workflow: The conditions named in this note are not included in G71.21. When the record documents both, both may be reported; the note is a boundary, not a prohibition.

  CompareQ74.3, M60

  See the official tabular notes · Guidelines I.A.12.b

Every row is derived from this code’s own record — its title, tabular notes, 7th-character family and same-category siblings — with fixed MedCoder wording; nothing is inferred about a patient. The official notes and guideline text are in the sections each row links to, and they control.

Indexed Clinical Terms (4)

Official source data — entries quoted as published, in the Index’s own lookup phrasing

Clinical term phrases from the official ICD-10-CM Index to Diseases and Injuries that map to this code. These are alphabetic-index entries shown as the Index writes them — lookup phrasing, not necessarily the wording of a final diagnosis.

• Disease, diseased, nemaline body
• Disease, diseased, rod body
• Myopathy, nemaline
• Myopathy, rod (body)

Don’t confuse G71.21 with…

MedCoder analysis — pairs from this code’s official notes, distinctions written by MedCoder

The codes most likely to be picked instead of G71.21 — named in its own official notes, or sharing its laterality or encounter family — with what separates them and which documentation moves the case. Each links to the full comparison.

• G71.20— Specificity relationship (Review)

  Overlapping diagnoses in the same category.

  Overlapping codes in the same category — the documentation decides which is the more specific fit.

  What moves you there: A record that documents no more than “Congenital myopathy, unspecified” takes G71.20; specificity in the record moves it back here.

  Full comparison: G71.21 vs G71.20 →

• Q74.3— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of arthrogryposis multiplex congenita adds Q74.3; it is not part of this code and both may be reported when both are documented.

  Full comparison: G71.21 vs Q74.3 →

• E70— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of metabolic disorders adds E70; it is not part of this code and both may be reported when both are documented.

  Full comparison: G71.21 vs E70 →

• E88— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of metabolic disorders adds E88; it is not part of this code and both may be reported when both are documented.

  Full comparison: G71.21 vs E88 →

• M60— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of myositis adds M60; it is not part of this code and both may be reported when both are documented.

  Full comparison: G71.21 vs M60 →

Relationships are read from this code's own official notes, its laterality siblings and its encounter family; the wording of each distinction is MedCoder editorial, and the documentation named in each “what moves you there” line is the official note phrase or sibling title itself. Source: CMS ICD-10-CM tabular instructional notes; ICD-10-CM Official Guidelines, Section I.A.12.a.

Verify Before Coding

• CC as a secondary diagnosis (FY2026). Can raise the stay's MS-DRG severity tier.

From the code registry, the Medicare Code Editor, and the MS-DRG Definitions Manual. Check it against a full claim in Claim Check.

Relationships & Classification

MedCoder structured relationships — computed from published CMS and AHRQ datasets

Other codes that name G71.21 or its code family, from the CMS ICD-10-CM tabular instructional notes. Tabular-note edges are stored at the code family level that carries each note.

Referenced by 5 Excludes2 notes: M60 — Myositis (via G71.-), M60-M63 — Disorders of muscles (M60-M63) (via G71.-), M61 — Calcification and ossification of muscle (via G71.-), M62 — Other disorders of muscle (via G71.-), M63 — Disorders of muscle in diseases classified elsewhere (via G71.-).

These codes’ tabular lists name this diagnosis as distinct — both may be reported when both are documented.

Referenced by 1 Code First instruction: M62.84 — Sarcopenia (via G71.-).

Each of these codes carries a Code First note naming this condition — when that code is reported, THIS code is sequenced first, ahead of it.

MS-DRG Grouper Relationships (FY2026)

Potential MS-DRG participation — not a DRG assignment.

FY2026 MS-DRG: CC — Complication or Comorbidity. Reported as a secondary diagnosis, this code raises the stay's MS-DRG severity tier — except when the principal diagnosis is one of 22 clinically related codes on its CMS exclusion list.

Named in the grouper logic of 3 MS-DRGs: DRG 091 (MDC 01), DRG 092 (MDC 01), DRG 093 (MDC 01).

From the CMS MS-DRG Definitions Manual (Appendices B and C). Actual DRG assignment depends on the complete claim.

Clinical classification (AHRQ CCSR):NVS018 — Myopathies (default).

Clinical Classifications Software Refined (CCSR) for ICD-10-CM Diagnoses. Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality.

Related Codes

Same clinical process (MS-DRG)

Acts as CC — raises the severity of other admissions. CMS groups these diagnoses into one MS-DRG principal-diagnosis exclusion process — a CC/MCC on this list never raises severity when the principal diagnosis is also on it.

G71.01 — Duchenne or Becker muscular dystrophy, G71.02 — Facioscapulohumeral muscular dystrophy, G71.031 — Autosomal dominant limb girdle muscular dystrophy, G71.032 — Autosomal recessive limb girdle muscular dystrophy due to calpain-3 dysfunction, G71.033 — Limb girdle muscular dystrophy due to dysferlin dysfunction, G71.0340 — Limb girdle muscular dystrophy due to sarcoglycan dysfunction, unspecified, G71.0341 — Limb girdle muscular dystrophy due to alpha sarcoglycan dysfunction, G71.0342 — Limb girdle muscular dystrophy due to beta sarcoglycan dysfunction, G71.0349 — Limb girdle muscular dystrophy due to other sarcoglycan dysfunction, G71.035 — Limb girdle muscular dystrophy due to anoctamin-5 dysfunction, G71.036 — Limb girdle muscular dystrophy due to fukutin related protein dysfunction, G71.038 — Other limb girdle muscular dystrophy, G71.039 — Limb girdle muscular dystrophy, unspecified, G71.09 — Other specified muscular dystrophies, G71.20 — Congenital myopathy, unspecified, G71.220 — X-linked myotubular myopathy, G71.228 — Other centronuclear myopathy, G71.29 — Other congenital myopathy, G96.9 — Disorder of central nervous system, unspecified, G98.8 — Other disorders of nervous system, +1 more

Same CMS-HCC risk category (V28)

CMS maps these diagnoses to the same Hierarchical Condition Category (Muscular Dystrophy) for risk-adjusted payment.

G71.00 — Muscular dystrophy, unspecified, G71.01 — Duchenne or Becker muscular dystrophy, G71.02 — Facioscapulohumeral muscular dystrophy, G71.031 — Autosomal dominant limb girdle muscular dystrophy, G71.032 — Autosomal recessive limb girdle muscular dystrophy due to calpain-3 dysfunction, G71.033 — Limb girdle muscular dystrophy due to dysferlin dysfunction, G71.0340 — Limb girdle muscular dystrophy due to sarcoglycan dysfunction, unspecified, G71.0341 — Limb girdle muscular dystrophy due to alpha sarcoglycan dysfunction, G71.0342 — Limb girdle muscular dystrophy due to beta sarcoglycan dysfunction, G71.0349 — Limb girdle muscular dystrophy due to other sarcoglycan dysfunction, G71.035 — Limb girdle muscular dystrophy due to anoctamin-5 dysfunction, G71.036 — Limb girdle muscular dystrophy due to fukutin related protein dysfunction, G71.038 — Other limb girdle muscular dystrophy, G71.039 — Limb girdle muscular dystrophy, unspecified, G71.09 — Other specified muscular dystrophies, G71.11 — Myotonic muscular dystrophy, G71.20 — Congenital myopathy, unspecified, G71.220 — X-linked myotubular myopathy, G71.228 — Other centronuclear myopathy, G71.29 — Other congenital myopathy

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Myopathies).

G71.038 — Other limb girdle muscular dystrophy, G71.039 — Limb girdle muscular dystrophy, unspecified, G71.09 — Other specified muscular dystrophies, G71.11 — Myotonic muscular dystrophy, G71.12 — Myotonia congenita, G71.13 — Myotonic chondrodystrophy, G71.14 — Drug induced myotonia, G71.19 — Other specified myotonic disorders, G71.2 — Congenital myopathies, G71.20 — Congenital myopathy, unspecified, G71.220 — X-linked myotubular myopathy, G71.228 — Other centronuclear myopathy, G71.29 — Other congenital myopathy, G71.3 — Mitochondrial myopathy, not elsewhere classified, G71.8 — Other primary disorders of muscles, G71.9 — Primary disorder of muscle, unspecified, G72.0 — Drug-induced myopathy, G72.1 — Alcoholic myopathy, G72.2 — Myopathy due to other toxic agents, G72.3 — Periodic paralysis, +53 more

Same Index main term, other category

The ICD-10-CM Index to Diseases and Injuries files this code under the main term “Myopathy”; these codes share that main term but sit in a different category of the Tabular List.

E20.9 — Hypoparathyroidism, unspecified (in, hypoparathyroidism), E21.3 — Hyperparathyroidism, unspecified (in, hyperparathyroidism NEC), E23.0 — Hypopituitarism (in, hypopituitarism), E24.9 — Cushing's syndrome, unspecified (in, Cushing's syndrome), E27.1 — Primary adrenocortical insufficiency (in, Addison's disease), E34.9 — Endocrine disorder, unspecified (endocrine NEC), E74.00 — Glycogen storage disease, unspecified (in, glycogen storage disease), E75.6 — Lipid storage disorder, unspecified (in, lipid storage disease), E85.0 — Non-neuropathic heredofamilial amyloidosis (in, amyloidosis), E88.9 — Metabolic disorder, unspecified (in, metabolic disease NEC), G72.0 — Drug-induced myopathy (in, drugs), G72.1 — Alcoholic myopathy (alcoholic), G72.2 — Myopathy due to other toxic agents (toxic), G72.49 — Other inflammatory and immune myopathies, not elsewhere classified (immune NEC), G72.81 — Critical illness myopathy (intensive care), G72.89 — Other specified myopathies (specified NEC), G72.9 — Myopathy, unspecified, H05.82 — Myopathy of extraocular muscles (extraocular muscles), M30.0 — Polyarteritis nodosa (in, polyarteritis nodosa), M31.6 — Other giant cell arteritis (in, giant cell arteritis), +10 more

Contextual Map

Every relationship of G71.21 in one view: hierarchy, official tabular instructions in both directions, clinical classification, risk adjustment, MS-DRG participation, index terms and change history — each edge carrying the CMS source it derives from.

Run G71.21 with these 6 related codes in Claim Check

Hierarchy

• G00-G99 — Chapter 6: Diseases of the Nervous System (G00-G99) (G00-G99)[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026

Referenced by Excludes2 notes

• M60 — Myositis[Excludes2](via G71.-): “muscular dystrophies and myopathies (G71-G72)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• M60-M63 — Disorders of muscles (M60-M63)[Excludes2](via G71.-): “muscular dystrophies and myopathies (G71-G72)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• M61 — Calcification and ossification of muscle[Excludes2](via G71.-): “muscular dystrophies and myopathies (G71-G72)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• M62 — Other disorders of muscle[Excludes2](via G71.-): “muscular dystrophies and myopathies (G71-G72)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
• M63 — Disorders of muscle in diseases classified elsewhere[Excludes2](via G71.-): “muscular dystrophies and myopathies (G71-G72)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Referenced by Code First instructions

• M62.84 — Sarcopenia[Code First](via G71.-): “primary disorders of muscles (G71.-)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Clinical classification (CCSR)

• NVS018 — Myopathies[CCSR]— AHRQ CCSR for ICD-10-CM Diagnoses (HCUP)

Risk adjustment (CMS-HCC)

• HCC 197 — Muscular Dystrophy [CMS-HCC]— CMS-HCC V28 · 2026

MS-DRG Grouper

• CC — Complication or Comorbidity [MS-DRG severity]: “As a secondary diagnosis this code can raise the stay's MS-DRG severity tier (CC).”— CMS MS-DRG Definitions Manual (Appendix C) · FY2026
• DRG 091 — OTHER DISORDERS OF NERVOUS SYSTEM WITH MCC[MS-DRG]: “OTHER DISORDERS OF NERVOUS SYSTEM WITH MCC (MDC 01)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026
• DRG 092 — OTHER DISORDERS OF NERVOUS SYSTEM WITH CC[MS-DRG]: “OTHER DISORDERS OF NERVOUS SYSTEM WITH CC (MDC 01)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026
• DRG 093 — OTHER DISORDERS OF NERVOUS SYSTEM WITHOUT CC/MCC[MS-DRG]: “OTHER DISORDERS OF NERVOUS SYSTEM WITHOUT CC/MCC (MDC 01)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026

MDC crossing

• MDC 01 — Diseases and Disorders of the Nervous System[MDC crossing]: “Diseases and Disorders of the Nervous System — the grouper's crossing between diagnoses and procedures: a principal diagnosis sets the MDC, and same-MDC procedures move the stay to its surgical DRGs. 8,892 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2026

Index entries

• Disease, diseased, nemaline body[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
• Disease, diseased, rod body[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
• Myopathy, nemaline[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
• Myopathy, rod (body)[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026

Nearest codes (34)

• G71 — Primary disorders of muscles[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• G71.0 — Muscular dystrophy[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• G71.00 — Muscular dystrophy, unspecified[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• G71.01 — Duchenne or Becker muscular dystrophy[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• G71.02 — Facioscapulohumeral muscular dystrophy[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• G71.03 — Limb girdle muscular dystrophies[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• G71.031 — Autosomal dominant limb girdle muscular dystrophy[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• G71.032 — Autosomal recessive limb girdle muscular dystrophy due to calpain-3 dysfunction[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• and 26 more

Change history

• FY2021 — Added to the code set[Change history]— CMS release files (code change ledger) · icd10cm-fy2021

Sources for this page

Codes, titles, notes, index terms and mappings on this page are transcribed from the datasets below. Relationships MedCoder computed and text MedCoder wrote are labelled where they appear.

Code, title, tabular notes and index terms Official source data

CMS/CDC ICD-10-CM FY2026 tabular list, index and tables, effective October 1, 2025 Release, file and checksum · Publisher’s page

Claim edits Official source data

CMS Definitions of Medicare Code Edits — v43.1 (April 2026) Release, file and checksum · Publisher’s page

Inpatient payment groups Official source data

CMS MS-DRG Definitions Manual (incl. Appendix B diagnosis index, Appendix C CC/MCC list, Appendix E procedure index) and IPPS Final Rule tables — v43 Release, file and checksum · Publisher’s page

Risk adjustment Official source data

2026 Mid-Year Final ICD-10 Mappings + Model Software (cms.gov/files/zip/2026-midyear-final-icd-10-mappings.zip, 2026-midyear-final-model-software.zip) — CMS-HCC V28, PY2026 mid-year final release Release, file and checksum · Publisher’s page

Change history and date-of-service validity Official source data

CMS ICD-10-CM release addenda, ingested release by release into the change ledger Release, file and checksum · Publisher’s page

Comparisons, relationships and the contextual map MedCoder structured relationship

Computed by MedCoder from the tabular notes and tables above; every derived relationship is marked as derived where it appears

Summary and FAQ answers MedCoder explanation

Written by MedCoder to explain the sources above: drafted with AI assistance, checked by a person against the release files, and labelled as MedCoder text where it appears. Not official text.

Labels on this page: Official source data · MedCoder structured relationship · MedCoder explanation. How to read the labels · All data sources and release dates

Nearest Codes in This Family

Official ICD-10-CM classifications closest to G71.21 in its code family, with their registry titles.

• G71.13 — Myotonic chondrodystrophy
• G71.14 — Drug induced myotonia
• G71.19 — Other specified myotonic disorders
• G71.2 — Congenital myopathies
• G71.20 — Congenital myopathy, unspecified
• G71.22 — Centronuclear myopathy
• G71.220 — X-linked myotubular myopathy
• G71.228 — Other centronuclear myopathy
• G71.29 — Other congenital myopathy
• G71.3 — Mitochondrial myopathy, not elsewhere classified

View all codes in the G71 family