sekelompok keadaan dengan bermacam-macam etiologi yang ditandai penimbunan protein fibrilar yang tak-dapat larut (amyloid) dalam berbagai organ dan jaringan tubuh, sehingga fungsi vital terganggu. Keadaan penyakit terkait dapat berupa inflamasi, penyakit herediter, atau neoplasia, dan deposisinya dapat terjadi setempat atau generalisata atau sistemik. Klasifikasi yang paling banyak digunakan dibuat berdasarkan sifat kimia serat amyloid, meliputi bentuk primary (AL), secondary (AA), dan familial.
|Classic facial features of AL amyloidosis with purpura around the eyes|
|Classification and external resources|
|Specialty||Endocrinology, Rheumatology, Cardiology|
Amyloidosis is a rare and serious disease caused by accumulation of proteins in the form of abnormal, insoluble fibres, known as amyloid fibrils, within the extracellular space in the tissues of the body. Amyloid deposits can be confined to only one part of the body or a single organ system in 'local amyloidosis' or they can be widely distributed in organs and tissues throughout the body in 'systemic amyloidosis'. The symptoms of amyloidosis are accordingly highly variable and confirmation of the presence of amyloid in the tissues can be challenging, so that diagnosis is often delayed.
Amyloid fibrils are formed by aggregation (clumping) of normally soluble body proteins and accumulate progressively, forming amyloid deposits which disrupt the normal tissue architecture, damaging the function of tissues and organs and causing disease. In contrast to the normally efficient clearance of abnormal debris from the tissues, amyloid deposits are removed very slowly, if at all. There are many different types of amyloidosis, each caused by formation of amyloid fibrils from different soluble precursor proteins in different patients. About 30 different proteins are known to form amyloid fibrils in humans and amyloidosis is named and classified according to the identity of the respective fibril protein.