Insulin resistance
DM causes muscle weakness, earlier onset of cataracts, and myotonia, which is delayed relaxation of muscles after contraction. Cataracts can be either a cortical cataract with a blue dot appearance, or a posterior subcapsular cataract. DM affects a wide variety of other organ systems as well. Symptoms may appear at any time from infancy to adulthood. Insulin resistance can occur. Presentation of signs and symptoms varies considerably by form (DM1/DM2), severity and even unusual DM2 phenotypes. DM1 and DM2 preferentially affect different muscles.