Some muscle diseases include muscular dystrophy, amyotrophic lateral sclerosis, spinal muscular atrophy, dermatomyositis and myasthenia gravis, according to Johns Hopkins Medicine. There are nine types of muscular dystrophy alone. The most well-known types of muscular dystrophy are Duchenne and Becker.
Duchenne muscular dystrophy typically appears between the ages of 2 and 6, and patients rarely survive past their 20s, according to Johns Hopkins Medicine. The disease first causes muscles to waste and weaken in the upper arms, upper legs and pelvis, and it eventually affects all the voluntary muscles. Patients with Becker muscular dystrophy usually first develop symptoms during adolescence or early adulthood. They exhibit the same types of symptoms as Duchenne muscular dystrophy patients, but the symptoms progress more slowly and are less severe, allowing for survival into middle age.
In amyotrophic lateral sclerosis, or ALS, the neurons that control voluntary muscles degenerate. This causes patients to progressively lose their ability to perform a wide range of functions, such as the ability to move limbs and breathe on their own, as explained by the National Institute of Neurological Disorders and Stroke. The disease is invariably fatal, and no cure exists as of 2015. Treatments such as nutritional support, physical therapy and speech therapy sometimes help improve quality of life for patients. Medications for depression, pain, muscle cramps and sleep difficulties also sometimes help patients manage the disease.