Muscle weakness. Dmd is a condition when muscles start to die prematurely. It starts in early childhood, leads to weakness of voluntary muscles such as those of hips, pelvic area, thighs and shoulders. Calves are often enlarged. Eventually it involves all muscles including that of heart and that control breathing. Life span is shortened to less than 30 years. It is a genetic condition primarily in boys.
Neuromuscular. X-linked which means it affects mainly boys. He gradually becomes weaker starting around age 3 to 5. Large calf muscles. Gowers sign (uses his hands to help him stand up). Confined to a wheelchair around age 12. Also affects muscles of heart. Affects lungs and bones/joints as well. Learning disability usually present. Diagnosis by blood test and/or muscle biopsy. Life expectancy is about 20 years.