 There are two main types of myotonic dystrophy.Type 1 (DM1), also known as Steinert disease, has a severe congenital form and a milder childhood-onset form as well as an adult-onset form.This disease is most often in the facial muscles, levator palpebrae superioris, temporalis, sternocleidomastoids, distal muscles of the forearm, hand intrinsic muscles, and ankle dorsiflexors.