SELDI-TOF mass spectrometry evaluation of variant transthyretins for diagnosis and pathogenesis of familial amyloidotic polyneuropathy.
BACKGROUND
Mass spectrometric analyses are valuable for detection of transthyretin (TTR) variants, which cause familial amyloidotic polyneuropathy (FAP). However, those methods require an immunoprecipitation step with an anti-TTR antibody and are not suitable for quantitative detection. We investigated the usefulness of SELDI-TOF mass spectrometry (MS) without an immunoprecipitation step.


METHODS
We used ProteinChips with chromatographic capture formats to detect TTRs. We attempted to correlate the intensity of mixed samples of amyloidogenic TTR (ATTR) V30M to wild-type (WT) TTR. We analyzed the proportion of ATTR V30M in amyloid-laden cardiac tissues from FAP patients, and also evaluated samples from FAP patients with 16 other TTR mutations.


RESULTS
Detection of ATTR required only 3 h of SELDI-TOF MS analysis. We determined that SELDI-TOF MS was suitable for quantitative detection of ATTR V30M and demonstrated that the proportion of ATTR V30M to WT TTR was 46.6% in amyloid-laden cardiac tissue from an FAP patient who died 10 years after liver transplantation. With this method, we identified 12 of 17 TTR variants. Small mass shifts and low concentrations of variants prevented ATTR detection. By changing the analytical conditions, we achieved detection of low concentrations of ATTR Y114C in serum.


CONCLUSIONS
SELDI-TOF MS is a reliable tool for quantitative evaluation of TTR variants, in both tissue amyloid deposits and body fluids. This method is useful for the diagnosis and investigation of the pathogenesis of FAP.
Ueda
Mitsuharu
M
Department of Diagnostic Medicine, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan. mueda5@fc.kuh.kumamoto-u.ac.jp
Misumi
Yohei
Y
Mizuguchi
Mineyuki
M
Nakamura
Masaaki
M
Yamashita
Taro
T
Sekijima
Yoshiki
Y
Ota
Kazutoshi
K
Shinriki
Satoru
S
Jono
Hirofumi
H
Ikeda
Shu-ichi
S
Suhr
Ole B
OB
Ando
Yukio
Y
D028227:Amyloid Neuropathies, Familial / Q000175:diagnosis* / Q000209:etiology* / Q000235:genetics; D006801:Humans; D011228:Prealbumin / Q000032:analysis*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
D011228:Prealbumin