Mel, it takes two mutations to cause Becker's, the recessive form. Thomsen's only requires one mutation.

If you want to email me the results I can check in the genetic database that I have. There are also mutations on the sodium ion channel that can cause myotonia. Do you know if they checked both chloride and sodium channels?

Thomsen's and Becker's are not considered to be progressive. We are just as susceptible to other conditions as we age so many people feel worse as they get older, but that is true in the general population, also.

Jan

Type of Myotonia: Thomsen's

Country: USA