VITREOUS OPACITIES IN PRIMARY FAMILIAL AMYLOIDOSIS

Amyloidosis may occur as localized deposition or as a systemic disorder and it is characterized by the deposition of amyloid in various organs and tissues. The exact nature of the amyloid substance remains unclear, as does its pathogenesis. I t is probably not a uniform chemical substance, but a group of closely related glycoproteins. In systemic amyloidosis the substance is deposited in various body tissues. Many classifications of amyloidosis have been suggested, of which the classification of Reimann et al. (1935) has been generally accepted: 1. primary amyloidosis, 2 . secondary amyloidosis, 3. tumor-forming amyloidosis and 4 amyloidosis associated with multiple myeloma. This classification, which is mainly based on the anatomical distribution of amyloid in various organs, has been completed and in part replaced by a differentiation according to the site of inital amyloid deposition (Missmahl 1959, Heller et al. 1964) : peri-reticulin amyloidosis, with initial depostion along reticular fibres; peri-collagen amyloidosis, with initial depostion along collagen fibres. The pattern of amyloid deposition can be observed in the early stages by means of polarized light microscopy, the vascular lesions being of the best differential character. Systemic amyloidosis is generally known to be either secondary to other diseases, or of unknown ethiology. In spite of the early reports of familial cases (Ostertag 1932, 1950. Maxwell and Kimbell 1936), it is less well known that it may be genetically determined. On the basis of clinical, genetic and pathological data, the inherited amyloidoses have been divided into three groups (Missmahl 1964, Gafni et al. 1964). The nephropathic group, represented particularly by the familial Mediterranean fever, is of the peri-reticulin type. The cardiopathic group described in a Danish family (Frederiksen et al. 1962) and the neuropathic group has a peri-collagen distribution of amyloid. Sporadic cases of systemic amyloidosis with involvement of the nervous system had previously been described when Andrade in 1952 reported 64 cases of generalized amyloidosis occurring endemically in Portugal and with