Becker Disease; Myotonia Congenita, Autosomal Recessive (MCR); However, in some rare cases, onset may occur as late as approximately 18 years of age.
ADULT-ONSET DM1 This is the most common form of myotonic dystrophy. People may have mild disease or severe complications. Mild DM1 may be associated.
The CTG repeat size in adult onset is generally in the range of 50 to 1,000.1. The mild form of DM1 is characterized by mild weakness, myotonia, and cataracts.
In autosomal recessive myotonia congenita, the average age of onset is slightly older. In both conditions, onset may be as late as the third or.