The main symptom is a weakness that usually starts in the lower arms or legs. But the different forms of DD tend to get worse in different ways. Some examples include:
· Distal myopathy with vocal cord and throat (pharyngeal) weakness affects the hands, legs, and voice. It may cause difficulty swallowing. It usually happens between the ages of 35 and 60.
· Finnish (tibial) distal myopathy affects the legs, particularly the muscles near the shin. It usually shows up after age 40, and most people with this DD can still walk throughout their life. People who inherit 2 copies of the defective gene may have more severe weakness beginning in childhood. They may not be able to walk later. Their heart may also be affected.
· Hereditary inclusion-body myopathy type 2 shows up between ages 25 and 40. It usually weakens the foot and thigh.
· Miyoshi distal myopathy causes weakness that begins in the calf muscles. It shows up between ages 15 and 30. Some people with this form of DD may eventually be unable to walk.
· Nonaka distal myopathy affects the muscles near the shin first. It then affects muscle groups in the upper arm, upper leg, and neck. The thigh muscle (quadriceps) usually stays healthy.
· Welander distal myopathy usually affects the arms first, and then the legs. It shows up in people between ages 40 and 50.
Your symptoms may differ from those described above. The different forms of DD may cause slightly different symptoms and progression.