It is classified as Thomsen (autosomal dominant) or Becker (autosomal recessive) generalized myotonia mainly based on the inheritance pattern.
[medvik.cz]
Dominant; Thomsen Disease; Disease, Thomsen; Generalized Myotonia, Becker; Myotonia, Becker Generalized; Myotonia, Generalized, Becker; Myotonia Congenita, Autosomal Recessive
[cismef.org]
Dominant Myotonia Congenita, Autosomal Recessive Myotonia Levior Myotonia, Becker Generalized Myotonia, Generalized Myotonia, Generalized, Becker Myotonias, Generalized Thomsen
[online-medical-dictionary.org]