Transthyretin Val30Met familial amyloid polyneuropathy: a considerably different clinical picture and natural course in endemic and non-endemic areas

Familial amyloid polyneuropathy (FAP) is caused by a mutation in the transthyretin (TTR) gene, which produces an amyloidogenic variant form of TTR (ATTR), thus leading to the designation of ATTR type FAP. Until now, more than 100 mutations have been identified as a cause of the gene abnormality in this disease, but the substitution of methionine for valine at position 30 (ATTR Val30Met) is the most common. FAP was once considered to be a disease peculiar to endemic areas, but FAP patients are now known to exist in many nations worldwide.1 The clinical phenotypes of ATTR type FAP have been …