The protein composition of the amyloid differentiates the amyloidosis types: serum A protein in the case of amyloidosis associated with chronic inflammatory diseases (aa amyloidosis), immunoglobulin light chain in AL amyloidosis, dialysis-associated β2-microglobulin in aβ2m amyloidosis, transthyretin (TTR) or other plasma protein in hereditary systemic amyloidosis. The gene discussed is TTR; the disease is AL amyloidosis.