A group of rare renal diseases, characterized by amyloid fibril deposition of apolipoprotein A-I or A-II (AApoAI or AApoAII amyloidosis), lysozyme (ALys amyloidosis) or fibrinogen A-alpha chain (AFib amyloidosis) in one or several organs. Renal involvement leading to chronic renal disease and renal failure is a common sign. Additional manifestations depend on the organ involved and the type of amyloid fibrils deposited.

Cerebral amyloid angiopathy (CAA), defined by the deposition of congophilic material in the vessels of the cortex and leptomeninges, is a major cause of intracerebral hemorrhage in the elderly (Vinters, 1987, Greenberg, 1998). Palsdottir et al. (1988) referred to the disorder in Icelandic patients as hereditary cystatin C amyloid angiopathy (HCCAA).

The Finnish type of systemic amyloidosis is characterized clinically by a unique constellation of features including lattice corneal dystrophy, and cranial neuropathy, bulbar signs, and skin changes. Some patients may develop peripheral neuropathy and renal failure. The disorder is usually inherited in an autosomal dominant pattern; however, homozygotes with a more severe phenotype have also been reported (Meretoja, 1973).