Anticipation in early- but not late-onset familial amyloid polyneuropathy (TTR Met 30) in Japan

Cases of familial amyloid polyneuropathy with the Met 30 transthyretin mutation (FAP TTR Met 30) occurring at an early age in Japan are characterized by the following: onset in the second to third decade; a high penetrating rate; initial symptoms including marked autonomic dysfunction, prominent pain, and thermal sensory involvement; and steady progression of disease over 10 to 15 years.1 These patients with an early onset reside in two high prevalence areas—the village of Ogawa on the island of Honshyu and the city of Arao on the island of Kyushyu. In contrast, because of advances in DNA diagnosis, late-onset cases of FAP TTR Met 30 with symptoms appearing at or over age 50 years now are recognized to occur widely throughout Japan; these cases show no relationship …