Abstract
We assessed the involvement of cutaneous innervation in two subjects with a molecularly confirmed diagnosis of spinobulbar muscular atrophy (SBMA) using antidromic nerve conduction studies, quantitative sensory testing, and sweat tests, as well as immunohistochemical techniques and confocal microscopy of glabrous and hairy skin biopsy. Both patients showed a marked reduction in amplitude of sensory action potentials and moderate or severe abnormalities of tactile thresholds and mechanical pain perception. A severe reduction of sweat drops on the Silastic imprint test and a widespread loss of small myelinated and unmyelinated fibers in hairy skin were also observed. Fiber loss involved either somatic or autonomic fibers and did not show any distal-proximal gradient. These results, together with loss of Meissner corpuscles and their large myelinated afferent fibers in glabrous skin, confirmed the extensive involvement of sensory neurons of large and small size and revealed an autonomic skin denervation in SBMA.
MeSH terms
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Adult
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Autonomic Nervous System Diseases / etiology
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Autonomic Nervous System Diseases / physiopathology
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Autonomic Pathways / pathology*
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Autonomic Pathways / physiopathology
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Biopsy
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Cell Size
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Electrodiagnosis / instrumentation
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Electrodiagnosis / methods
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Ganglia, Spinal / pathology
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Ganglia, Spinal / physiopathology
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Humans
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Male
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Middle Aged
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Muscular Atrophy, Spinal / diagnosis*
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Muscular Atrophy, Spinal / pathology
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Muscular Atrophy, Spinal / physiopathology*
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Nerve Fibers, Myelinated / pathology
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Nerve Fibers, Unmyelinated / pathology
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Neural Conduction
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Neurons, Afferent / pathology
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Predictive Value of Tests
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Sensory Receptor Cells / pathology*
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Sensory Receptor Cells / physiopathology
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Sensory Thresholds
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Skin / innervation
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Skin / pathology*
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Skin / physiopathology*
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Somatosensory Disorders / etiology
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Somatosensory Disorders / physiopathology
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Sweat Gland Diseases / etiology
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Sweat Gland Diseases / physiopathology
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Sweat Glands / innervation
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Sweat Glands / physiopathology
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Sympathetic Fibers, Postganglionic / pathology
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Sympathetic Fibers, Postganglionic / physiopathology
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Wallerian Degeneration / etiology
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Wallerian Degeneration / physiopathology