The condition usually occurs when the mother already has myotonic dystrophy type 1 (although she may not be aware of it) and then it is passed on to her child in a more severe form. Very occasionally it can be passed on by an affected father, but this only occurs in one percent of cases. For more information about myotonic dystrophy type 1, please visit our myotonic dystrophies pages.
The symptoms of congenital myotonic dystrophy appear from birth. In other kinds of myotonic dystrophy the symptoms usually appear in early adulthood.
Please note: congenital myotonic dystrophy is not the same as congenital myopathy or congenital muscular dystrophy.
How common is it?
This condition is very rare. However there are families, groups and specialists known to Muscular Dystrophy UK who you can contact for support, advice and information.
How severe is it?
Up to 25 percent of affected children may not survive past their first birthday. Children who live beyond this are likely to live into adulthood.