Low yield in screening patients with sporadic motor neuron disease for Kennedy disease

Intern Med J. 2007 Nov;37(11):772-4. doi: 10.1111/j.1445-5994.2007.01499.x.


The diagnostic yield of testing for Kennedy disease in patients diagnosed with sporadic motor neuron disease (MND) is unclear. We measured the CAG repeat lengths in the androgen receptor gene of patients with progressive limb weakness who had either upper and lower motor signs (n = 130), or lower motor neuron signs alone (n = 30). Only one patient with a long history of lower motor weakness had a repeat length in the Kennedy disease range. Testing for Kennedy disease is unlikely to benefit MND patients with upper motor neuron signs or those with a short history of lower motor signs.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Chromosomes, Human, X
  • DNA
  • Diagnosis, Differential
  • Female
  • Genetic Diseases, X-Linked / diagnosis*
  • Humans
  • Male
  • Mass Screening*
  • Middle Aged
  • Motor Neuron Disease / diagnosis*
  • Motor Neuron Disease / genetics*
  • Receptors, Androgen / genetics*
  • Repetitive Sequences, Nucleic Acid
  • Trinucleotide Repeat Expansion


  • Receptors, Androgen
  • DNA