2020 Volume 57 Issue 2 Pages 106-109
Hereditary transthyretin (ATTRv) amyloidosis, also known as familial amyloid polyneuropathy (FAP), is a disease caused by the systemic deposition of variant transthyretin (TTR). Although this disease was primarily indigenous to endemic foci in Portugal, Japan, and Sweden, its prevalence has increased throughout the world. Val30Met, one of the most common TTR mutations, exhibits varying characteristic features in the early-onset patients from conventional endemic foci and the late-onset patients from non-endemic areas. Severe autonomic dysfunctions and dissociated sensory loss are the characteristic features of the former, whereas mild autonomic dysfunctions and loss of all sensory modalities are observed in the latter. Distortion and atrophy of the Schwann cells due to the formation of amyloid fibrils seem to cause predominant small-fiber loss in the early-onset patients, while other mechanisms, such as microangiopathy and the toxicity of TTR oligomers, may contribute to nerve fiber loss in the late-onset patients.
