Which histologic findings are characteristic of X-linked spinobulbar muscular atrophy (SBMA) (Kennedy disease)?

Updated: Apr 28, 2014
  • Author: Hidehiro Takei, MD; Chief Editor: Adekunle M Adesina, MD, PhD  more...
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The cardinal histopathologic feature of X-linked spinobulbar muscular atrophy (SBMA) is loss of neurons in the anterior horns and motor nuclei in the spinal cord and brainstem. Motor nuclei of CNs III, IV, and VI are spared. Sensory neurons in the dorsal root ganglia are less severely affected, and large myelinated fibers demonstrate a distally accentuated sensory axonopathy in the peripheral nervous system. [45, 46]

The neurons in the Onufrowicz nuclei, intermediolateral columns, and Clarke columns of the spinal cord are generally well preserved, as is the case in ALS. [46] Muscle biopsy shows neurogenic atrophy of varying degree.

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