Kennedy's Disease

Kennedy's disease is an inherited disease that affects males. It affects movement (motor) ability. It is one of a group of disorders called spinal muscular atrophy (SMA). Onset of the disease is usually between the ages of 20 and 40. Although, it has been diagnosed in men from their teens to their 70s.


Kennedy's disease is caused by a defective gene. This gene is passed down on the mother's side. Daughters of patients with Kennedy's disease are also carriers. Female carriers have a 1 in 2 chance of having a son affected with the disease. Parents with concerns about their children may wish to talk to a genetic counselor.


Early symptoms include:

  • Tremor of the outstretched hands.

  • Muscle cramps with exertion.

  • Fleeting muscle twitches visible under the skin.

Eventually, individuals develop limb weakness. This usually begins in the pelvic or shoulder regions. Weakness of the facial and tongue muscles may occur later in the course of the disease and often leads to:

  • Dysphagia (difficulty in swallowing).

  • Dysarthria (slurring of speech).

  • Recurrent aspiration pneumonia.

Some individuals develop:

  • Enlargement of male breasts (gynecomastia) and low sperm count.

  • Infertility.

  • Non-insulin-dependent diabetes mellitus.


Currently there is no known cure for Kennedy's disease. Treatment is symptomatic and supportive. Physical therapy and rehabilitation to slow muscle weakness and atrophy may prove helpful.