So I took Jan's advice and got a DNA test because I was told I had Thompsens but neither one of my parents has it. The test results came in and they say I have 1 dominant or 2 recessive genes which is a mutated version of myotonia and that is why my parents do not have it. My children have a 25% chance of having it but they are still
Symptom free. I thought this sounded wierd so I was just checking to see if anyone else had a mutated version of myotonia?

Thanks,
Mindy

Type of Myotonia: Thompsens

Country: US

I'm sitting here going, "Huh?" It doesn't make much sense. Spontaneous mutations for myotonia congenita are extremely rare, so it's more likely that your parents each carried a recessive gene. It's not totally out of the question, but you would only have one mutation, not two, if it were spontaneous, and for you to have symptoms it would be a dominant form (Thomsen's).

If you can email me the copy of your report or send me the exact mutation/mutations they identified I'll see what I can find on a genome database. The mutation will be a letter, three numbers and another letter. For instance mine is G230E.

All myotonia congenita is caused by mutations. The most common are a substitution of one amino acid for another in the coding for the subunits of the chloride ion channel. Others are deletions, insertions, splices and nonsense mutations. Each type has a little bit different effect on the function of the chloride channel.

Jan

Type of Myotonia: Thomsen's

Country: USA