Familial amyloid polyneuropathy associated with the transthyretin Cys114 gene in a Japanese kindred.

A Japanese kindred with dominantly inherited amyloid polyneuropathy, commonly called familial amyloid polyneuropathy (FAP), has been identified. Amyloid protein was transthyretin (TTR) related and the patients were heterozygous for the mutant gene encoding TTR with a single amino acid substitution of cysteine for tyrosine at position 114. This family originated in Nagasaki Prefecture, Japan, and 12 of the 36 known members of six generations have been affected. The initial symptoms occurred in their thirties with the cardinal features of polyneuropathy, vitreous opacities and cardiac disease. Sensory neuropathy was severe in the lower limbs. Autonomic disturbances, especially postural hypotension, were the most debilitating to the patients. Amyloid deposits were detected widely in most organs except for the central nervous system. The duration from the onset of the disease to death was within 10 yrs. Heart failure caused by heavy amyloid deposits was the most common cause of sudden death.