Age associated axonal features in HNPP with 17p11.2 deletion in Japan.
OBJECTIVE
To clarify age related changes in the clinicopathological features of hereditary neuropathy with liability to pressure palsy (HNPP) in Japanese patients with deletion of 17p11.2, particularly concerning axonal abnormalities.


METHODS
Forty eight proband patients from 48 HNPP families were assessed as to clinical, electrophysiological, and histopathological features, including age associated changes beyond those in controls.


RESULTS
Motor conduction studies showed age associated deterioration of compound muscle action potentials in nerves vulnerable to repetitive compression (median, ulnar, and peroneal nerves), but not in others such as the tibial nerve. Sensory conduction studies revealed more profound reduction of action potentials than motor studies with little age related change. Large myelinated fibre loss was seen in the sural nerve irrespective of age at examination.


CONCLUSIONS
Irreversible axonal damage may occur at entrapment sites in motor nerves in HNPP patients, progressing with aging. Sensory nerves may show more profound axonal abnormality, but without age association. The electrophysiological features of HNPP are presumed to be a mixture of abnormalities occurring from early in life and acquired features caused by repetitive insults at entrapment sites. Unlike Charcot-Marie-Tooth disease type 1A, age associated axonal damage may not occur unless the nerves are subjected to compression.
Koike
H
H
Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan.
Hirayama
M
M
Yamamoto
M
M
Ito
H
H
Hattori
N
N
Umehara
F
F
Arimura
K
K
Ikeda
S
S
Ando
Y
Y
Nakazato
M
M
Kaji
R
R
Hayasaka
K
K
Nakagawa
M
M
Sakoda
S
S
Matsumura
K
K
Onodera
O
O
Baba
M
M
Yasuda
H
H
Saito
T
T
Kira
J
J
Nakashima
K
K
Oka
N
N
Sobue
G
G
D000200:Action Potentials / Q000502:physiology; D000328:Adult; D000367:Age Factors; D000375:Aging / Q000502:physiology; D001369:Axons / Q000473:pathology*; D002886:Chromosomes, Human, Pair 17 / Q000235:genetics*; D004252:DNA Mutational Analysis; D015342:DNA Probes / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics; D005260:Female; D017353:Gene Deletion; D015417:Hereditary Sensory and Motor Neuropathy / Q000208:ethnology* / Q000235:genetics* / Q000503:physiopathology; D006801:Humans; D007564:Japan; D008297:Male; D018482:Muscle, Skeletal / Q000294:innervation / Q000473:pathology / Q000503:physiopathology; D009185:Myelin Proteins / Q000235:genetics; D009413:Nerve Fibers, Myelinated / Q000473:pathology; D009431:Neural Conduction / Q000502:physiology; D009469:Neuromuscular Junction / Q000473:pathology / Q000503:physiopathology; D010525:Peripheral Nerves / Q000473:pathology / Q000503:physiopathology
D015342:DNA Probes; D018076:DNA, Complementary; D009185:Myelin Proteins; C073687:PMP22 protein, human