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G71.13 vs Q77

G71.13 (Myotonic chondrodystrophy) compared with Q77 (Osteochondrodysplasia with defects of growth of tubular bones and spine), from the official CMS tabular data.

Current data releases:ICD-10-CM FY2027 · ICD-10-PCS FY2027 · HCPCS October 2026 · MS-DRG v44 · Medicare Code Editor v44.0 · NCCI PTP Q4 2026 · MUE Q4 2026 · NCD code lists 2026-01 · LCD export September 28, 2026 · All releases and sources

Summary

These codes can be reported together when both conditions are documented, because Q77 lists G71.13 under Excludes2, which marks them as distinct conditions.

Official rule
What is different?

The conditions named, billing status and chapter.G71.13 is “Myotonic chondrodystrophy”; Q77 is “Osteochondrodysplasia with defects of growth of tubular bones and spine”. Q77 is a non-billable header; G71.13 is billable. G71.13 sits in G00-G99 — Diseases of the Nervous System (G00-G99); Q77 in Q00-QA1 — Congenital Malformations, Deformations and Chromosomal Abnormalities (Q00-QA1).

Registry fact

Can these codes be reported together?

Yes, when both are documented.Q77 lists G71.13 under Excludes2: “congenital myotonic chondrodystrophy (G71.13)”. Excludes2 marks distinct conditions that may both be reported when both are documented.

Official ruleGuide: Excludes1 vs Excludes2

Is there an Excludes2 relationship?

Yes.Q77’s tabular entry: “congenital myotonic chondrodystrophy (G71.13)”. The note covers G71.13.

Official ruleGuide: Excludes1 vs Excludes2

Is one a parent or header code?

One is a header.Q77 is a non-billable header, but G71.13 is not one of its subdivisions.

Registry fact

Nothing found in 3 other checks; 1 check does not apply
Is there an Excludes1 relationship?

None.Neither entry carries an Excludes1 note that names the other code. Q77 carries 1 Excludes1 note covering other codes; the side-by-side table quotes them.

Official rule

Is one more specific?

Not comparable.The codes sit in different categories; specificity is only comparable within one category.

Are there sequencing instructions?

None.Neither entry carries a Code First or Use Additional Code note that names the other.

Official rule

Are there other coding relationships?

None found.No laterality, encounter-phase, Table of Neoplasms, Table of Drugs and Chemicals, or history-versus-active-disease relationship links these codes.

MedCoder-derived

Official rule: a tabular instructional note or a section of the ICD-10-CM Official Guidelines, quoted as published. Registry fact: the codes’ own published attributes (titles, billable status, position in the hierarchy, code set). MedCoder-derived: a reading MedCoder computes from those facts; it is not itself a rule. How to read the labels

Can these codes be reported together?

Informational

Excludes2 relationship

Q77
Osteochondrodysplasia with defects of growth of tubular bones and spine
↔
G71.13
Myotonic chondrodystrophy

What we found

Yes, when both are documented.Q77 carries an Excludes2 note covering G71.13: “congenital myotonic chondrodystrophy (G71.13)”

Excludes2 marks distinct conditions — both may be reported when both are documented.

What to review

Report both only when the documentation supports both conditions; otherwise report the one documented.

Guide: Excludes1 vs Excludes2Check these on a claim

Why it matters

An Excludes2 note means the excluded condition is not part of the code above it, but a patient can have both. Report both when both are documented.

Source / rule

CMS ICD-10-CM tabular instructional notes

Official guidance behind these answers

  • Section I.A.12.b — Excludes2 · applies to: Excludes2

    A type 2 Excludes note represents “Not included here.” An excludes2 note indicates that the condition excluded is not part of the condition represented by the code, but a patient may have both conditions at the same time. When an Excludes2 note appears under a code, it is acceptable to use both the code and the excluded code together, when appropriate.

    ICD-10-CM Official Guidelines FY2027

Quoted from the ICD-10-CM Official Guidelines for Coding and Reporting in effect for the release shown. The tabular notes above are the code-level instruction; these sections are the convention that says how such a note is applied. Source document (CMS PDF) · Release and checksum

Side by side

Similar descriptions do not make codes interchangeable. The documentation and the official instructions decide which code applies.

Official descriptionDiffers
G71.13

Myotonic chondrodystrophy

Q77

Osteochondrodysplasia with defects of growth of tubular bones and spine

StatusDiffers
G71.13
Billable
Q77
Non-billable header

A header is not reported on a claim; a code beneath it is.

Report instead: Q77.0, Q77.1, Q77.2, Q77.3, Q77.4

Excludes1Differs
G71.13

None at this code

Q77
  • mucopolysaccharidosis (E76.0-E76.3)
Excludes2Differs
G71.13
  • arthrogryposis multiplex congenita (Q74.3)
  • metabolic disorders (E70-E88)
  • myositis (M60.-)
Q77
  • congenital myotonic chondrodystrophy (G71.13)
CategoryDiffers
G71.13

G71 Primary disorders of muscles

Q77

Is itself a category

ChapterDiffers
G71.13

G00-G99 — Diseases of the Nervous System (G00-G99)

Q77

Q00-QA1 — Congenital Malformations, Deformations and Chromosomal Abnormalities (Q00-QA1)

IncludesDiffers
G71.13
  • Chondrodystrophic myotonia
  • Congenital myotonic chondrodystrophy
  • Schwartz-Jampel disease
Q77

None at this code

No Code first, Use additional code, Code also and 7th character note at either code.

Notes are the code’s own tabular entry, quoted as published. A note that names the other code is the one the verdict above rests on. In a row that differs, each code’s own notes are listed under it, and the notes every code shares are listed once beneath them.

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Derived from the official CMS ICD-10-CM tabular data (FY2027). A coding-rule comparison, not billing advice: payer-specific edits and medical-necessity policy are outside its scope. All data sources