ICD-10 G71.12
Billable / SpecificMyotonia congenita
About ICD-10-CM G71.12
ICD-10-CM code G71.12 represents Myotonia congenita. This is a billable/specific code in the Nervous System chapter (block G71). The 2026 edition of ICD-10-CM G71.12 became effective on October 1, 2025.
Inclusion Terms / Approximate Synonyms
Clinical terms and conditions classified under G71.12. Per CMS ICD-10-CM Tabular 2026.
- Acetazolamide responsive myotonia congenita
- Dominant myotonia congenita [Thomsen disease]
- Myotonia levior
- Recessive myotonia congenita [Becker disease]
Medicare Advantage HCC Impact
Capture this diagnosis annually for accurate risk adjustment. Missed HCC captures are the #1 revenue leak in Medicare Advantage risk programs.
Medicare LCD Coverage for G71.12
Local Coverage Determinations (LCDs) from CMS MACs that list G71.12 as a covered diagnosis.
Showing top 10 of 624 total . Click a CPT for full coverage scope.
Commercial Payer Coverage
Coverage policies from major commercial payers referencing G71.12.
1 Cigna
5 Medicare
1 Aetna
CPT Codes Commonly Billed with G71.12
Procedures frequently paired with this diagnosis based on PayerReady's Dx↔Px linkage data.
Convert G71.12 to ICD-9-CM
Per CMS General Equivalence Mappings (GEMs), useful for legacy data review and historical claim analysis.
| ICD-10 | ICD-9 | Mapping Flags |
|---|---|---|
| G71.12 | 35922 | 00000 |
Flags format (5 digits): Approximate · No Map · Combination · Scenario · Choice List. Source: CMS 2017 GEMs (final version).
Codes Adjacent To G71.12
Other codes in section G70-G73 (Diseases of myoneural junction and muscle).
ICD-10 G71.12, Billing FAQ
Is ICD-10 code G71.12 billable? +
Yes, G71.12 is a billable ICD-10-CM code that can appear as a primary or secondary diagnosis on claims.
What other names or terms map to G71.12? +
ICD-10 G71.12 includes: Acetazolamide responsive myotonia congenita; Dominant myotonia congenita [Thomsen disease]; Myotonia levior, and 1 more clinical synonyms.
What CPT codes are commonly billed with G71.12? +
Procedures frequently paired with G71.12 include: G0161, G0153.
What ICD-9 codes does G71.12 map to? +
Per CMS GEMs, G71.12 maps to ICD-9 codes: 35922. Useful for legacy data review and historical claim analysis.
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Reviewed by the PayerReady Medical Coding Team
Verified against the CMS 2026 code set on June 1, 2026.
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