X-linked spinal and bulbar muscular atrophy

Other names

Kennedy's disease

Pathophysiology

It is an inherited motor neuron disease that affects males.

Lower motor neuron disorder

It is one of a group of disorders called lower motor neuron disorders (which involve disruptions in the transmission of nerve cell signals in the brain to nerve cells in the brain stem and spinal cord).

Onset

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.

Symptoms

Early symptoms include tremor of the outstretched hands, muscle cramps with exertion, and fasciculations (fleeting muscle twitches visible under the skin). Eventually, individuals develop limb weakness which usually begins in the pelvic or shoulder regions.

Clinical course

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), and recurrent aspiration pneumonia.

Gynecomastia

Some individuals develop gynecomastia (excessive enlargement of male breasts) and low sperm count or infertility.

Diabetes

Still others develop non-insulin-dependent diabetes mellitus.

Inheritance

Kennedy's disease is an x-linked recessive disease, which means the patient's mother carries the defective gene on one of her X chromosomes.

Carriers

Daughters of patients with Kennedy's disease are also carriers and have a 1 in 2 chance of having a son affected with the disease.

Genetic counseling

Parents with concerns about their children may wish to talk to a genetic counselor.

Prognosis

Prognosis is fair as most have a normal lifespan although some will be wheel chair bound in the later stages of the disease.

Cure

Currently there is no known cure for Kennedy's disease.

Treatment

Treatment is symptomatic and supportive. Physical therapy and rehabilitation to slow muscle weakness and atrophy may prove helpful.

• Disease-Information-Page Kennedy's Disease at NINDS

• Wikipedia