Two transthyretin variants (TTR Ala-49 and TTR Gln-89) in two Sicilian kindreds with hereditary amyloidosis.

We report the biochemical and molecular characterization of two new transthyretin (TTR) variants in two Italian families with hereditary amyloidosis. Both families presented neuropathy and cardiomyopathy but they differ in other clinical features. These TTR variants were previously detected by isoelectric focusing (IEF); one is a neutral TTR variant and the other one is basic. By protein and DNA analysis the neutral variant was found to have a substitution of an alanine for a threonine residue at position 49 (TTR Ala-49) of the polypeptide chain. The basic variant has a glutamine residue replacing glutamate at position 89 (TTR Gln-89).