title: The significance of carpal tunnel syndrome in transthyretin Val30Met familial amyloid polyneuropathy.
abstract: Carpal tunnel syndrome (CTS) is frequently reported in association with amyloidosis. We determined the significance of CTS in transthyretin Val30Met-associated familial amyloid polyneuropathy (FAP ATTR Val30Met) by comparing the electrophysiological indices of the median and ulnar nerves in 58 patients. As a whole, sensory nerve conduction velocity (SCV) was slowed and distal motor latency (DML) was prolonged to a similar extent in the median and ulnar nerves in these patients. The extent of abnormalities in the median nerve was almost similar to that in the ulnar nerve in both early-onset cases from endemic foci and late-onset cases from non-endemic areas. In age-matched idiopathic patients with CTS (20 patients, 27 hands), the slowing of SCV and the prolongation of DML in the median nerve were significant, while the slowing of motor conduction velocity was much less compared to FAP ATTR Val30Met patients. Although concomitant lesions in the ulnar nerve entrapment site at the wrist cannot be excluded, these findings indicate that CTS is not the sole distinctive feature in the majority of FAP ATTR Val30Met patients. The electrophysiological abnormality at the distal portion of the median nerve may be a consequence of polyneuropathy rather than an entrapment injury.
authors.affiliation: Department of Neurology, Nagoya University Graduate School of Medicine, Aichi, Japan.
authors.forename: Haruki
authors.initials: H
authors.lastname: Koike
authors.forename: Saori
authors.initials: S
authors.lastname: Morozumi
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Kawagashira
authors.forename: Masahiro
authors.initials: M
authors.lastname: Iijima
authors.forename: Masahiko
authors.initials: M
authors.lastname: Yamamoto
authors.forename: Naoki
authors.initials: N
authors.lastname: Hattori
authors.forename: Fumiaki
authors.initials: F
authors.lastname: Tanaka
authors.forename: Tomohiko
authors.initials: T
authors.lastname: Nakamura
authors.forename: Masaaki
authors.initials: M
authors.lastname: Hirayama
authors.forename: Yukio
authors.initials: Y
authors.lastname: Ando
authors.forename: Shu-Ichi
authors.initials: S
authors.lastname: Ikeda
authors.forename: Gen
authors.initials: G
authors.lastname: Sobue
mesh_terms: D000328:Adult; D000368:Aged; D019943:Amino Acid Substitution; D028227:Amyloid Neuropathies, Familial / Q000235:genetics / Q000473:pathology; D002349:Carpal Tunnel Syndrome / Q000235:genetics / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D008475:Median Nerve / Q000473:pathology / Q000502:physiology; D008875:Middle Aged; D009431:Neural Conduction / Q000502:physiology; D011228:Prealbumin / Q000235:genetics*; D014459:Ulnar Nerve / Q000473:pathology / Q000502:physiology
chemical_list: D011228:Prealbumin