Kate,

I think you are wise to get tested for myotonic MD before having children. Myotonia congenita is relatively stable throughout generations and it doesn't seem to matter if it's passed on by the father or the mother. The mutation is in the chloride channel of the skeletal muscle, whereas mytonic MD is a mutation in a protein kinase gene that can vary greatly from person to person.

Myotonic muscular dystrophy may be mild or even unnoticeable without an EMG and DNA test if it comes through the father, but if the mother passes on the gene, the next generation is generally worse, and by the third generation through female inheritance there is usually profound weakness and mental impairment from birth. As I recall many babies don't make it past the first few weeks.

I know many families with myotonic MD and the disease progression varies quite a bit. Like your father, many men don't even show signs until they are older (40s or 50s) and may have only experienced slight weakness and stiffness with muscles gradually starting to atrophy in the neck and face. The hormones related to pregnancy can exacerbate symptoms earlier in women and affect the baby.

The DNA testing for myotonic MD is widely available. Unfortunately if we want DNA testing for MC we have to send it overseas and wait for months or even years to get results.

If you don't get tested, I would strongly advise that you get checked for cataracts every year by a good opthamologist (not optometrist). There is a type of cataracts strongly associated with myotonic MD even if other symptoms are minimal.

Thanks for your input -

Jan

Yes, I have read that it can get worse for mothers to children. I also figured that since I was fortunate to know before I had children, I can nip it in the bud in my side of the family. My dad is not sure on which side he got it, but he is clearly worse than the previous family members, and is hardly able to walk anymore (the diagnosis was about 20 years ago, now). I couldn't even imagine having children without genetic testing first, and the information you gave me only makes that more obvious. After all, we don't know when there will be a cure, and I am not going to gamble with my family.
As I said, my dad is getting worse. He has already experienced the sleep apnea, and has developed a heart murmer. He is also so weak sometimes he can't make it down the stairs, and he falls often. On the other hand my aunt only has the thinner face and cataracts which she has had removed. Thanks for keeping me on track about my eyes. Do you think my dad and/or I should wear a bracelet regarding general anesthesia? With all his falling and the number of times he has gone to the hospital, I wouldn't want them to not know he shouldn't be under? He doesn't have one now, but I might be able to convince him to get one if it is a good idea? Thanks. Kate