[Application to transthyretin analysis].

Transthyretin (TTR) is the precursor protein of familial amyloidotic polyneuropathy (FAP) and senile systemic amyloidosis (SSA). TTR-related FAP is a hereditary amyloidosis induced by mutated TTR. The most common type of FAP is FAP amyloidogenic TTR (ATTR) Val30Met: TTR substitution of methionine for valine at position 30 of the TTR sequence. In this type of FAP, amyloid deposition causes organ failure including peripheral neuropathy, autonomic disorders, gastrointestinal symptoms, and cardiac and renal failure. In Japan, it is well known that Kumamoto and Nagano are the two major foci of FAP, but recently, FAP has been found throughout Japan. In addition, various different types of mutations in the TTR gene and phenotypes of FAP have also been documented. Medical care for FAP is becoming more important. Detection of mutant TTR is indispensable to diagnose the disease in order to treat FAP. We have developed a method for detecting mutant TTR in serum and cerebrospinal fluid by means of mass spectrometry to screen for variant TTR in FAP patients. In this article, we reviewed the general characteristics of TTR and clinical features of FAP, and described the identification of mutant TTR using surface-enhanced laser desorption/ionization time-of-flight (SELDI-TOF) mass spectrometry (MS). In addition, we analyzed TTR modifications and protein profiles in serum samples of Japanese and Swedish patients using SELDI-TOF-MS to look for a key protein(s) as a trigger of FAP.