Clinical features of spinal and bulbar muscular atrophy

Lindsay E. Rhodes, Brandi K. Freeman, Sungyoung Auh, Angela D. Kokkinis, Alison La Pean, Cheunju Chen, Tanya J. Lehky, Joseph A. Shrader, Ellen W. Levy, Michael Harris-Love, Nicholas A. Di Prospero, Kenneth H. Fischbeck

Research output: Contribution to journalArticlepeer-review

145 Scopus citations


Spinal and bulbar muscular atrophy is an X-linked motor neuron disease caused by a CAG repeat expansion in the androgen receptor gene. To characterize the natural history and define outcome measures for clinical trials, we assessed the clinical history, laboratory findings and muscle strength and function in 57 patients with genetically confirmed disease. We also administered self-assessment questionnaires for activities of daily living, quality of life and erectile function. We found an average delay of over 5 years from onset of weakness to diagnosis. Muscle strength and function correlated directly with serum testosterone levels and inversely with CAG repeat length, age and duration of weakness. Motor unit number estimation was decreased by about half compared to healthy controls. Sensory nerve action potentials were reduced in nearly all subjects. Quantitative muscle assessment and timed 2 min walk may be useful as meaningful indicators of disease status. The direct correlation of testosterone levels with muscle strength indicates that androgens may have a positive effect on muscle function in spinal and bulbar muscular atrophy patients, in addition to the toxic effects described in animal models.

Original languageEnglish (US)
Pages (from-to)3242-3251
Number of pages10
Issue number12
StatePublished - Dec 2009

All Science Journal Classification (ASJC) codes

  • Clinical Neurology


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