Kennedy’s Disease

Kennedy’s Disease (KD) is a rare neuromuscular disease and a form of adult-onset Spinal Muscular Atrophy (SMA) that is a result of mutations in the Androgen Receptor gene on the X chromosome. There are small increases in one specific region of the gene. The larger the increases, the earlier the onset and the more pronounced the symptoms.

KD is also known as Spinal Bulbar Muscular Atrophy (SBMA). It is an inherited chromosomal X-linked recessive disease that affects the spinal and bulbar neurons causing muscle wasting (atrophy) predominantly in the legs, arms, face and throat. It is estimated that one in 40,000 people worldwide have KD.

Neurological Symptoms

  • Weakness of tongue and mouth muscles
  • Problems breathing (breathy speech pattern)
  • Difficulty swallowing
  • Poor articulation
  • Changes in voice and speech (harsh or strained voice, decrease in range of pitch)
  • Numbness
  • Hand tremors
  • Decreased or absent deep tendon reflexes

Muscular Symptoms

  • Twitching of muscles when at rest (Fasciculations)
  • Cramps: Large muscle spasms
  • Increased calf size due to cramps
  • Loss of muscle bulk

Other Symptoms

  • Erectile dysfunction
  • Breast enlargement (Gynecomastia)
  • Impotence
  • Decreased size and function of testicles
  • Low sperm count

Other Facts and Characteristics

  • Late onset: Symptoms usually develop in the late 30’s or later
  • Progresses quite slowly
  • Those living with KD have a nearly normal lifespan
  • Females are rarely affected but can be carriers and experience a mild expression of the disease


Many people are not diagnosed for years. Due to similarities in symptoms, many people are misdiagnosed with ALS. KD can be diagnosed easily with a simple DNA blood test. Very often KD diagnosis is done between the ages of 20-50 years.


To date, KD is incurable and there are no treatments. Some people living with the disease do take prescribed medications to alleviate symptoms. Patients have reported that stretching exercises can help ease cramps and pain.

To learn more about Kennedy’s Disease click here.

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