Spinal Bulbar Muscular Atrophy – SBMA

This is a rare, X-linked recessive neuromuscular disease, caused by a mutation in the androgen receptor. It may also be due to de novo mutations. It affects both spinal and medulla nerves, causing muscle weakness and atrophy mainly in limbs, face and neck. Symptoms begin during adulthood between 30 and 50 years of age, but they may start earlier or later than these ages. Men show symptoms, while women are carriers of the disease, but in rare cases they may experience even milder symptoms. The incidence of the disease is 1: 40,000 worldwide.


  • Speech problems (dysphonia – dysarthria).
  • Swallowing and chewing problems.
  • Muscle cramps and stings.
  • Trembling.
  • “Jaw hanging”.
  • Reduced mobility.
  • Gynecomastia.
  • Infertility and impotence.
  • Inguinal hernia .
  • Pneumonia due to aspiration.
  • insulin-non – dependent diabetes.

Older women (60-70 years old) may experience cramping and stinging.



  • Clinical examination.
  • Medical history.
  • Blood tests for CK enzyme, testosterone, luteinizing hormone, progesterone, follicle – stimulating hormone.
  • Genetic test.
  • Electromyography.
  • Nerve signal transduction speed test.



It is symptomatic and includes physical therapies, rehabilitation therapies, medication to treat cramps and trembling, hormone therapy and surgical restoration of gynecomastia, feeding tube fitting, respiratory support, use of supportive means of movement (eg walking stick, wheelchair).


To follow-up clinical trials on the disease visit: https://clinicaltrials.gov/ct2/home






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