[Epidemiological and clinical aspects of non-hereditary systemic amyloidosis]

The amyloidoses are a large group of postsecretory protein misfolding and deposition diseases. There are over 20 secreted human proteins whose misfolding and misassembly outside the cell is linked to amyloidosis. In this paper, we described epidemiological and clinical aspects of non-hereditary systemic amyloidosis, including senile systemic amyloidosis (SSA) and systemic AL amyloidosis. SSA, induced by wild-type transthyretin (TTR) deposition, is a prevalent aging-related disorder, as about 25% of people over age 80 have TTR deposition in the heart, but it is usually detected by microscopic examination at autopsy. Although SSA is usually associated with cardiac disease, TTR deposition is not limited to the heart and is found in systemic organs. Carpal tunnel syndrome is one of the most common clinical manifestations of SSA and often precedes cardiac symptoms. Systemic AL amyloidosis is the most common non-hereditary systemic amyloidosis induced by immunoglobulin light chain deposition. Involvement of visceral organs usually dominates the clinical picture of systemic AL amyloidosis, but some patients suffer from serious peripheral neuropathy, including polyneuropathy, carpal tunnel syndrome, and autonomic dysfunction. High-dose melphalan with stem cell transplantation improves prognosis of systemic AL amyloidosis including neurological symptoms.