Congenital Myotonic Dystrophy (CDM) is a multi-systemic, dominantly inherited disorder caused by a trinucleotide repeat expansion (CTGn) in the DMPK gene. CDM occurs when the CTGn increases between the adult myotonic dystrophy type-1 (DM1) parent and the child. Children with CDM present at birth with respiratory insufficiency, talipes equinovarus, feeding difficulties and hypotonia. There is a 30% mortality rate in the first year of life. As children grow, they are at risk for intellectual impairment, autistic features, gastrointestinal symptoms, and motor delay.

The investigators will enroll children with CDM between ages 0-15 with visits at baseline and one year to evaluate appropriate physical functional outcomes, cognitive function and quality of life over time. Functional outcome measures will be correlated with potential biomarkers in the children. Completion of these specific aims will extend the understanding of disease progression in CDM and will provide the requisite information for successful therapeutic trials in children with DM.

CDM Group

Inclusion Criteria:

• Age 0-15 yrs
• Diagnosis of CDM, based on symptoms and genetic testing of expanded trinucleotide repeats.

Exclusion Criteria:

• Any other non-DM1 illness that would interfere with the ability or results of the study in the opinion of site investigator
• Significant trauma within one month
• Internal metal or devices

Control Group

Inclusion Criteria:

• Age 0-15 yrs
• Healthy children on no medication

Exclusion Criteria:

• Any illness or situation that, in the opinion of the site investigator, has the possibility to interfere with study procedures
• DM type 1 and 2

This study proposes a longitudinal evaluation of 100 children with CDM and 50 healthy controls, stratified into the following age cohorts: 0-2 years, 11 months; 3 years to 6 years, 11 months; and 7 years and older. The age cohorts are created to ensure an even distribution across all ages.