Amyloidoses – pathogenesis, classification, diagnosis

Amyloidoses – also known as amyloidosis or betafibrillosis – a diverse group of diseases in which amorphous protein with a changed conformational structure is deposited extracellularly, leading to the failure of many organs. The basic classifications of amyloidoses take into account: the type of precursor protein, the division into generalized (systemic) amyloidoses, in which amyloid deposits accumulate in many organs, vessel walls and connective tissue (e.g. AL amyloidosis) and local (localized) amyloidoses – limited to only one organ (e.g. corneal amyloidosis) as well as congenital and acquired diseases. Symptoms of amyloidosis are non-specific and not very characteristic, moreover, their severity depends on the type of disease and organ involvement. The diagnosis of amyloidosis should be considered in patients with heart failure without coronary artery disease, with neuropathy, or proteinuria or hepatomegaly of unclear origin. Diagnosis of amyloidosis is based on the evaluation of tissue biopsy samples and the presence of abnormal proteins, i.e. amyloid, or on the fibrillary evaluation confirmation of the filamentous nature of amyloid deposits using electron microscopy. The next step is differential diagnosis and amyloid differential identification, which is based on immunohistochemical and immunofluorescence studies using labeled antibodies. The "gold standard" used in typing amyloidosis and identifying an amyloidogenic protein is mass spectrometry. Laboratory tests are used to assess organ involvement, which is the basis of the prognostic classification.