We report the clinical features of a patient with hereditary transthyretin (ATTR) amyloidosis associated with a novel mutation (Y114S, p.Y134S). A 65-year-old Japanese man was admitted to our hospital after a 3-year history of progressive dyspnea on exertion. Five years previously, he presented dysesthesia in both hands caused by carpal tunnel syndrome. A genetic analysis revealed a base pair substitution of adenine to cytosine in the second codon of exon 4, residue 114, in the TTR gene (c.401A>C). The clinical characteristics were progressive cardiomyopathy with a poor vital prognosis, late onset, sporadic case, bilateral carpal tunnel syndrome, hypothyroidism, and small fiber neuropathy.