The material extracted by these solvents has been shown to contain the major amyloid proteins, which characterize the various amyloid types: the 8 kDa amyloid A in AA amyloidosis, the 12–20 kDa light chain fragments in AL, or the TTR monomers (14 kDa) and their fragments in ATTR. The gene discussed is TTR; the disease is axial length measurement.