Chemical classification of hereditary amyloidosis in Brazilian families and identification of gene carriers.

Plasma prealbumin was isolated from individuals in 3 kindreds from Brazil with biopsy proven heredofamilial amyloidosis as well as from a number of asymptomatic family members. The prealbumin samples were cleaved with cyanogen bromide and the resulting peptide mixtures separated by reverse phase high performance liquid chromatography. The peptide elution pattern seen for the individuals with confirmed amyloidosis is consistent for the presence of a prealbumin variant with a methionine for valine at position 30 of the molecule. Sequence analysis of the isolated peptides confirms this observation and shows that the 3 Brazilian families investigated in our study have the same prealbumin variant as individuals with amyloidosis of Swedish/American, Portuguese and Japanese origins.