ICD-10-CM 2027 diagnosis code

G71.1Myotonic disorders

Not billable — use a more specific code

G71.1 is a header code, so it can't be reported by itself. Choose one of the 5 more specific codes beneath it.

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About G71.1

G71.1 is the ICD-10-CM diagnosis code for myotonic disorders. It belongs to category G71 (primary disorders of muscles), block G70-G73 (diseases of myoneural junction and muscle) and chapter 6 (diseases of the nervous system). It is a header code, so it can't be reported by itself; one of its 5 subcodes must be used instead.

Within G71 (primary disorders of muscles), G71.1 is specifically for myotonic disorders. Related codes cover muscular dystrophy (G71.0), congenital myopathies (G71.2), mitochondrial myopathy, not elsewhere classified (G71.3), other primary disorders of muscles (G71.8) and primary disorder of muscle, unspecified (G71.9).

To report this condition, pick the subcode that matches the documentation: G71.11 (dystrophy), G71.12 (congenita), G71.13 (chondrodystrophy), G71.14 (myotonia) and G71.19 (disorders).

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Specific codes under G71.1

Notes that apply from higher levels

Instructions written at a parent level also apply to G71.1.

› From G71 Primary disorders of muscles

Excludes2

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

Broader instructions also apply from Chapter 6: Diseases of the nervous system.

Codes whose notes reference G71.1

H28Code first

Code history

2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027

FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
No changes since FY2016.

Common questions about G71.1

Is G71.1 billable?: No. G71.1 is a header code. Report one of its more specific subcodes instead.