A Case Showing Specific Electrophysiological Findings of Bulbospinal Muscular Atrophy (Kennedy’s Disease)

J Korean Assoc EMG Electrodiagn Med 2006;8(1):56-61.
Published online May 10, 2006.

Abstract

Kennedy’s disease (bulbospinal muscular atrophy) is a very rare, X-linked recessive disease, and its diagnosis is confirmed by DNA analysis which shows abnormal expansion of CAG repeats. However, it has specific clinical and electrophysiological findings, and not all the patient with Kennedy’s disease should take the DNA studies. A 60-year-old man had suffered from slowly progressing four extremity weakness and dysarthria. His muscle power was checked as grade 4 in all extremities, and he had gynecomastia. Deep tendon reflexes were decreased, and there were systemic muscular atrophies, especially in the proximal muscles. He had diabetes mellitus for 7 years. There was no abnormal finding in CMAP. But in SNAP, we found delayed latencies, decreased amplitudes and no responses in some nerves. Needle EMG showed wide spread chronic denervation findings in most of examed muscles. Histopathologic findings showed chronic denervation atrophy. At this step, we could conclude this case as Kennedy’s disease and we recommended the DNA analysis for confirmative diagnosis and genetic counseling, and it showed abnormal expansion of CAG repeats in androgen receptor gene.

Key Words: Kennedy’s disease, Muscular atrophy, DNA analysis, CAG repeats

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