The profile of motor unit number estimation (MUNE) in spinal and bulbar muscular atrophy.
OBJECTIVE
Spinal and bulbar muscular atrophy (SBMA) is a lower motor neuron disease caused by the expansion of a trinucleotide CAG repeat in the androgen receptor (AR) gene. The fundamental histopathological finding of this disease is an extensive loss of lower motor neurons in the spinal cord and brainstem. It is, however, difficult to evaluate clinically the degree of motor neuron degeneration, which stresses the need for biomarkers to detect the remaining neuronal function.


METHODS
The authors performed motor unit number estimation (MUNE) in 52 patients with SBMA, to investigate whether this method could be a potential biomarker of SBMA, and re-evaluated MUNE 1 year later in a subgroup of the patients.


RESULTS
The number of functioning motor units was remarkably reduced in patients with SBMA compared with controls, and was correlated with both ipsilateral grip power and disease duration. A longitudinal analysis demonstrated a further reduction in motor units within 1 year.


CONCLUSIONS
The results suggest that MUNE is an electrophysiological parameter that reflects the severity and progression of motor neuron degeneration in patients with SBMA.
Suzuki
Keisuke
K
Department of Neurology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
Katsuno
Masahisa
M
Banno
Haruhiko
H
Takeuchi
Yu
Y
Kawashima
Motoshi
M
Suga
Noriaki
N
Hashizume
Atsushi
A
Hama
Tetsuo
T
Uchida
Kei
K
Yamashita
Fumitada
F
Nakamura
Tomohiko
T
Hirayama
Masaaki
M
Tanaka
Fumiaki
F
Sobue
Gen
G
D017668:Age of Onset; D000368:Aged; D015415:Biomarkers; D002452:Cell Count; D004247:DNA / Q000235:genetics; D018450:Disease Progression; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D018737:Hand Strength / Q000502:physiology; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009046:Motor Neurons / Q000473:pathology*; D018485:Muscle Fibers, Skeletal / Q000473:pathology*; D053580:Muscle Strength / Q000502:physiology; D020966:Muscular Disorders, Atrophic / Q000235:genetics / Q000473:pathology*; D009460:Neurologic Examination
D015415:Biomarkers; D004247:DNA