Myotonic Dystrophy (DM)

Childhood-Onset DM1

DM1 begins in early childhood (but not at birth) and typically presents before the age of 10. The first symptoms tend to be more behavioral and cognitive than physical. Intellectual impairment with low IQ is a common manifestation. Some people with childhood-onset DM struggle with attentional deficits, executive dysfunctions, and cognitive and behavioral problems. An "avoidant" or apathetic personality can be part of the picture.^{15, 16, 17, 18, 19, 20}

As the child matures into adulthood, typical features of adult-onset DM1 usually emerge. Serious cardiac rhythm disturbances may occur in asymptomatic adolescents with no or only subtle signs of DM. Sports and physical exercise precipitate arrhythmias in more than 50% of these patients.^{21, 22}

To learn more about the juvenile-onset form of DM1, be sure to read Childhood-Onset DM1 Can Cause Cognitive, Behavior Challenges (part of Quest's In Focus: Myotonic Dystrophy series).

References

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