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About Kennedy's Disease

What is Kennedy’s Disease?

Kennedy’s Disease, or X-linked motor neuron disease, is a rare inherited neuromuscular disorder also known as X-linked recessive bulbospinal neuropathy or X-linked spinal and bulbar atrophy. It is an adult onset, progressive disorder, characterised by the degeneration of lower motor neurons within the spinal cord and brainstem. This causes progressive weakening and wasting of the muscles particularly in the arms and legs.

Humans have 46 paired chromosomes, with two sex chromosomes that decide gender and 44 chromosomes that dictate other factors. The mother’s egg always provides a female sex chromosome known as ‘X’, while the father’s sperm contributes either an ‘X’ (female) or ‘Y’ (male) chromosome. A pairing of ‘XX’ sex chromosomes means the baby is a girl, while ‘XY’ means the baby is a boy. Kennedy’s disease is caused by a genetic mutation of the androgen receptor gene on the X chromosome.

Since the disease is recessive, the presence of the normal gene on the other X chromosome means that girls don’t develop the symptoms of disease, because the normal gene overrides the mutated one. However, these girls will be carriers, and each son of a carrier mother has a 50 per cent chance of inheriting the gene and developing the disease. This is because boys only receive one X chromosome and, if that has the mutated gene, they will one day develop the symptoms of Kennedy’s disease.

It is estimated that 1 in 40,000 people have this genetic defect and because it is relatively rare, Kennedy’s Disease is often initially misdiagnosed or goes undiagnosed for years. There is no cure for Kennedy’s disease and no current treatment available.

Facts of KD

  • it is a rare disease
  • there is no cure
  • the defect is in the ‘X’ Chromosome
  • generally it affects males
  • women are carriers (in rare cases they can suffer too)
  • testosterone becomes a poison to the body
  • the majority of the research funding’s has been private donations.

Living with KD

  • medications to reduce muscle cramps and tremors
  • plenty of rest and avoidance of exhaustion
  • healthy, balanced diet
  • gentle and regular aerobic exercise
  • regular stretching to help reduce muscle cramping
  • pain management
  • speech, occupational and physiotherapy.


The many symptoms of Kennedy’s disease generally first appear when the person is aged between 30 and 50 years old. Every case is different, but some form of physical disability will take hold. What starts with small trips and falls, can eventually lead to wheel chair confinement and full-time care.

Often symptoms begin with painful cramping and uncontrollable muscle spasms. Over time the disease will attack most of the muscles often making it difficult to even swallow liquids.

On-set symptoms can include any or all of the following

  • swallowing difficulties
  • speech difficulties
  • hand tremors
  • shaky muscles when holding certain postures
  • muscle weakness, wastage, twitches, cramps and spasms
  • enlarged calf muscles due to constant cramping
  • localised areas of numbness
  • absent reflexes
  • enlarged breast tissue (gynaecomastia)
  • impotence
  • low sperm count
  • shrunken testicles
  • reduced sex drive


How is KD diagnosed?

There are various methods of diagnoses. Your GP can refer you to a neurologist in your area and they can take a blood test to establish if KD is present. On some occasions a blood test isn’t necessary as the disease is visually recognisable and your neurologist can carry out certain physical tests at the appointment.

Who is affected by KD?

Men suffer with KD, however, there have been some rare cases of females suffering with the disease too.

When does KD kick in?

KD usually starts to affect people in the 30’s to 50’s.  There have been earlier reported cases and later reported cases too.

Is there any medication to take to help with the offset of the disease?

No. Some reports have been made that taking herbal remedies i.e. tumeric can alleviate muscle weakness but no trials have proved this helps.