We report on the genetic and molecular characterisation of an Italian family with a late-onset, autosomal dominant transthyretin amyloidosis. The transthyretin gene was analysed by polymerase chain reaction (PCR), restriction generating PCR, and sequencing, allowing us to discover in one allele a novel point mutation. It consists of a G to C transversion at position 1692 of the genomic sequence, leading to a Thr for Arg substitution at the position 34 of the polypeptidic chain. This mutation is associated with a severe sensory-motor peripheral neuropathy and a restrictive cardiomyopathy.