"Sporadic" prealbumin-related amyloid polyneuropathy: report of two cases.

Two "sporadic" cases of amyloid polyneuropathy are reported. There was no family history or plasma cell dyscrasia. Both showed sensorimotor and autonomic polyneuropathy with onset in the seventh decade. Amyloid deposits in both cases reacted with anti-human prealbumin sera but not with antisera to human AA and anti-human immunoglobulin light-chain amyloids, including A kappa and A lambda. One patient had the abnormal serum prealbumin and abnormal DNA sequence found in type I familial amyloid polyneuropathy (FAP)(Japanese type). Investigations in "sporadic" amyloid polyneuropathy should include immunohistochemistry, using antisera to the different amyloid proteins, and the radioimmunoassay and recombinant DNA techniques for diagnosis of FAP.