There are two well-defined types of the disease (DM1 and DM2) which have distinct but overlapping symptoms. Both DM1 and DM2 are characterized by muscle weakness and myotonia, heart abnormalities, cataracts and insulin resistance. In general, DM2 is less severe than DM1: fewer systems are affected, patients develop the disease only as adults, and the disorder’s impact on everyday life is relatively less disruptive

In contrast, DM1 can occur from birth to old age. Symptoms vary greatly among patients, from minor muscle pain to serious respiratory and cardiac issues. The congenital form of DM1 is the most severe version and has distinct symptoms that can be life-threatening.