G71.12 Myotonia congenita

Billable ICD-10-CM code, FY2026.

Applicable to

• Acetazolamide responsive myotonia congenita
• Dominant myotonia congenita [Thomsen disease]
• Myotonia levior
• Recessive myotonia congenita [Becker disease]

Applies from G71 Primary disorders of muscles

Excludes2 (not included here)

• arthrogryposis multiplex congenita (Q74.3)
• metabolic disorders (E70-E88)
• myositis (M60.-)

MS-DRG index

Defines the logic of DRG(s) 091-093 in MDC 01.

Approximate ICD-9-CM (GEMs)

• 359.22 Myotonia congenita

Code annotations containing back-references to G71.12

Back-references to G71.1

• Code First: H28 Cataract in diseases classified elsewhere ("myotonia (G71.1-)")

Back-references to G71

• Code First: M62.84 Sarcopenia ("primary disorders of muscles (G71.-)")

Diagnosis Index entries for G71.12

• Becker's › disease › myotonia congenita, recessive form
• Disease, diseased › Becker › myotonia congenita
• Disease, diseased › Thomsen
• Myotonia (acquisita) (intermittens) › congenita (acetazolamide responsive) (dominant) (recessive)
• Myotonia (acquisita) (intermittens) › levior
• Thomsen disease

Nearby codes

• G71.038 Other limb girdle muscular dystrophy
• G71.039 Limb girdle muscular dystrophy, unspecified
• G71.09 Other specified muscular dystrophies
• G71.1 Myotonic disorders
• G71.11 Myotonic muscular dystrophy
• G71.12 Myotonia congenita (this code)
• G71.13 Myotonic chondrodystrophy
• G71.14 Drug induced myotonia
• G71.19 Other specified myotonic disorders
• G71.2 Congenital myopathies
• G71.20 Congenital myopathy, unspecified