Jenna, I have just finished looking over some of your previous posts on weakness that you associate with Becker's MC, e.g., March 18, 2013. What you describe sounds exactly like what I have and am expereincing. The mutation I have on the CLCN1 is the same as another person diagnosed with Thomsen's MC. My mother reported mild stifness when she was pregnant. I have a cousin my age that reports myotonia sounding symptoms. It was only because of noticing the stiffness in my cousin that I asked for MC testing. Prior to that I had been tested for MDI and MDII and hyper-PP. Neither have had the degreee of difficulty that I have had. Both my mother and cousin have a more muscular appearance than do I.
Can you send or post the article you mentioned regarding depolarization in Becker's MC?
I also have a problem with weakness sometimes when it gets hot.
I have one of the more recent studies bookmarked on my computer but I'm not at home right now. However, if you go to scholar.google.come and type in "myotonia congenita" and weakness, you should pull a lot of studies up. I recommend using the date filer to the left of the page and limiting your results to no older than the year 2000 because in the older studies they did not have genetic testing and could not always distinguish the different myotonic disorders from one another by symptoms.