A site for medical students - Practical,Theory,Osce Notes

What is Kennedýs Disease?

It is an X-Linked Spinobulbar Muscular Atrophy .
Symptoms begins in males in midadult life
The main clinical manifestations are 
  • Lower motor neuron disorder in which there is progressive weakness and wasting of limb and bulbar muscles 
  • Features of androgen insensitivity manifested by gynecomastia and reduced fertility  .
Difference with ALS 
Two findings distinguishing this disorder from ALS are
  • The absence of signs of pyramidal tract disease (spasticity) 
  • The presence of a subtle sensory neuropathy in some patients. 
  • Gynecomastia is also a differentiating features 
Genetic abnormality
The underlying molecular defect in kennedy disease is an expanded trinucleotide repeat (-CAG-) in the first exon of the androgen receptor gene on X chromosome..There is an inverse correlation  between the number of -CAG- repeats and the age of onset of this disease. Genetic abnormality is detected with DNA testing