Childhood-Onset Myotonic Dystrophy: DM1
After a relatively normal birth and infancy, individuals with childhood-onset DM1 develop symptoms sometime between early childhood and early adolescence. The time of onset is often dependent on the astuteness of the observer.
Unlike classical DM1, which often first presents as a muscle disease, the symptoms of childhood-onset DM1 are frequently observed when school-aged patients visit a doctor because of mental development issues (such as learning disabilities or personality abnormalities). However, because many other diseases can cause similar symptoms, it might take several years to arrive at the correct diagnosis. If a parent reports a family history of DM1, then these behavioral issues may raise suspicion of the disorder. A clinical diagnosis often relies largely on the presence of characteristic facial features of DM and myotonia, although myotonia may not be present until children reach the teen years. Chronic, excessive fatigue is the most frequent symptom in later childhood and early adolescence.
As with adult-onset DM1, multiple systems can be affected. Cardiac problems such as irregular heartbeat and heart muscle damage may occur in the second decade of life, and can lead to severe, life-threatening complications. Mild motor problems occur in some patients, although they may be vague and only recognized as such after the DM diagnosis is made. Muscle weakness and other DM1 symptoms arise in the second and third decades, and tend to follow the progression seen with classical adult-onset DM1.
Although no disease-altering therapies exist, early diagnosis and symptomatic treatment can greatly improve the quality of life for individuals affected with this disorder. Early intervention and educational support are particularly important for children with mental development issues.
Regular monitoring of systems can identify potentially life-threatening conditions and allow patients to avoid or reduce complications seen as the disease progresses. This is particularly important when affected individuals become symptomatic in their second and third decades, as early onset tends to be associated with increased complications in later life.
More technical information on the symptoms, diagnosis and management of Childhood-Onset Myotonic Dystrophy: DM1 can be found by clicking here.