Amyloidosis Due to a Mutation of the Gelsolin Gene in an American Family with Lattice Corneal Dystrophy Type II

Abstract

AMYLOID is a homogeneous, largely extracellular, proteinaceous material with a fibrillar ultrastructure and the property of green birefringence when stained with Congo red and viewed by polarization microscopy. Depending on the associated disease or pathologic state, amyloid fibrils are composed of distinct subunit proteins, at least 13 molecular species of which have been described. The nomenclature adopted for fibril subunit proteins reflects the fact that most forms of amyloidosis are associated with serum protein precursors, which in several types of hereditary disease are variant molecules that can be identified by DNA-based techniques. An example of this nomenclature is AL for the subunit proteins in primary amyloidosis, which may be associated with multiple myeloma or Waldenström's macroglobulinemia. In this form of amyloidosis, fibrils are composed of polymerized immunoglobulin light chains or light-chain fragments. Other examples are AA for the subunit protein in reactive (secondary) amyloidosis and ATTR for amyloidosis due to deposition of transthyretin.^{1 , 2}