Myotonic dystrophy

Individuals with CTG repeats between 50 and 100-200 have the milder form of the disease spectrum. They most likely will have a normal or slightly shortened lifespan but symptoms can still have a significant impact on the quality of life, especially as the condition may have gone undiagnosed for many years. 

 Patients with the late-onset type usually present first signs in their forties. First signs can include cataracts, heart disease, or myotonia in their hands. Additional symptoms include those described for the adult form of myotonic dystrophy but the age at onset, severity and progression can significantly vary from one person to another. A diagnosis may only occur after a second or third-generation family member presents with more severe symptoms.