Myotonic Dystrophy Foundation

DM2 (also called Proximalin medicine, it refers to a part of the body that is nearest to the trunk of the body, such as thighs and upper arms. Myotonic Myopathy or PROMM) was the second form of myotonic dystrophy to be identified.  Because DM2 was only recently discovered, this form has been less frequently diagnosed than DM1and its different manifestations are still being researched. In general, DM2 tends to be less severe than DM1, with fewer systems affected and symptoms appearing later in life.  There is no congenital form of DM2 and it is rarely diagnosed in childhood or early adulthood.

Muscle complaints tend to be the first symptoms noted, with weakness, exercise-induced fatigue, transient or fluctuating pain, and mild myotoniathe inability of contracted muscles to relax on command; or, a special kind of muscle stiffness.. DM2 patients also present with symptoms occurring in muscle groups different from those in DM1: proximal muscles (i.e. those clustered closer to the trunk of the body, such as the thighs, hips and shoulders) are typically affected rather than distal muscles affected in DM1. More serious symptoms of proximal leg weakness, stiffness, difficulties climbing stairs, rising from a chair, or lifting are typically seen between the fourth and sixth decades.

DM2 patients do not generally have the pronounced facial weakness that is characteristic of DM1.  However, variability in muscle weakness have not yet been fully studied in DM2 to identify how DM2 manifests in facial muscle.

While issues with non-muscular systems have been noted in both diseases, the frequency and severity of those symptoms is less frequently reported and less well characterized in DM2. Reduced executive function, diabetes, and daytime sleepiness are the most common non-muscular symptoms reported by individuals with DM2.   Serious cardiac issues (such as heart attacks and other medical emergencies) occur less frequently than in DM1, but can occur even in young and asymptomatic patients. 

Although no disease-altering therapies exist, symptomatic treatment can improve the quality of life for individuals affected with this disorder. Regular monitoring of cardiac function can identify potentially life-threatening conditions and allow patients to avoid or reduce complications.

More technical informaiton on the symptoms, diagnosis and management of DM2 can be found by clicking here.