FAQs

Kennedy’s Disease, also known as Spinal and Bulbar Muscular Atrophy (SBMA), is a rare, inherited neuromuscular disorder that primarily affects males, though females can be carriers. It is a motor neuron disease, which involves the gradual degeneration of nerve cells responsible for controlling voluntary muscle movement.

Kennedy’s Disease is caused by a mutation in the androgen receptor (AR) gene located on the X chromosome. This mutation results in an abnormal expansion of the CAG repeat in the gene.

Diagnosis is confirmed with a genetic test that identifies the abnormal CAG repeat expansion in the AR gene. Additional tests may include neurological exams, EMG, and blood tests to rule out other conditions.

Unfortunately, there is no know treatment or cure, but researchers continue to make strides every year. Some individuals living with KD do take medications prescribed by their medical doctor to help alleviate various symptoms. Others have reported that a smart (light) exercise program coupled with stretching helps.  If you have questions, visit the KDA Forum or contact the KDA.

Kennedy's Disease is a motor neuron disease, which involves the gradual degeneration of nerve cells responsible for controlling voluntary muscle movement.

Motor neurons are long nerve cells that extend from your spinal cord to your muscles. These nerve cells fire to make your muscles contract. In KD, the nerve cells become dysfunctional and eventually die, leaving the muscles unable to contract.

The androgen receptor is a protein that resides inside the nerve cell. Many cells have the androgen receptor protein, but motor neurons have more than most. The binding of testosterone to an androgen receptor somehow causes the onset of the disease. Men are generally affected by KD because they have much higher levels of testosterone than women.

Generally males with the inherited gene develop symptoms, while females with the gene are carriers. In rare cases, females have been known to exhibit mild symptoms.

Symptoms often begin in adulthood, typically between ages 30 and 50, and progress slowly. Common symptoms include:

- Muscle weakness and wasting (especially in the arms and legs)
- Tremors
- Muscle cramps
- Difficulty swallowing (dysphagia)
- Speech difficulties
- Gynecomastia (enlarged breast tissue in males)
- Reduced fertility

Because the AR gene is located on the X chromosome, KD primarily affects males. Females can be carriers of the gene mutation and may experience mild symptoms such as muscle cramps or tremors, but rarely develop the full disease.

Yes. KD is inherited in an X-linked recessive pattern, meaning the faulty gene is passed down through the X chromosome. Carrier mothers have a 50% chance of passing the gene mutation to each child. Sons who inherit it will be affected; daughters who inherit it will be carriers.

It is estimated that 1 in 40,000 individuals worldwide have Kennedy's Disease.

No. While both are motor neuron diseases, Kennedy’s Disease is less aggressive than ALS and is not typically fatal. KD progresses slowly, and most individuals have a normal life expectancy. However, with KD, many individuals are undiagnosed or misdiagnosed for years. The most frequent misdiagnosis is the fatal Lou Gehrig's Disease (ALS).

The Kennedy’s Disease Association (KDA) provides educational resources, research updates, and community support for patients, carriers, families, and healthcare providers.