ICD-10-CM > G00-G99 > G70-G73 > G71 > G71.1 G71.1 Myotonic disorders Non-Billable/Non-Specific Codes G71.11Myotonic muscular dystrophyG71.12Myotonia congenitaG71.13Myotonic chondrodystrophyG71.14Drug induced myotoniaG71.19Other specified myotonic disorders