Hi Leia -
Since your MIL and husband both have whatever it is, it most likely was inherited just from 1 parent. If they do have MC, it is most likely Thomsen's - but if you are planning to have children (I know this was not mentioned), then he would certainly want to be tested, to know what he actually has, and what likelihood there is of transmitting it to the next generation.

If they do have Myotonia Congenita, as Jan said, the crippling contractures of the fingers would not be caused by that. It sounds like a type of arthritis, and I would encourage your husband to seek out a good doctor, have the DNA testing done, and also get a referral to a rheumatologist, and a hand therapist, for a program of preventive exercises, to minimize the extent of contracture and deformity, and stave it off for as long as possible.

Also, there are supplements (vitamins, minerals, etc) which are helpful to joints and tendons, to keep them as limber and healthy as possible. Avoiding sugar, caffeine, large amounts of red meat, alcohol and some other dietary considerations can also help minimize the pain and severity - and are also helpful for dealing with MC.

The DNA testing really does clarify things, making it more likely that you can identify interventions more specifically geared towards his issues.

Good luck! lois

Type of Myotonia: MC- Becker's type

Country: USA