Amyloid in hereditary amyloid polyneuropathy is related to prealbumin

The origin of amyloid in the several subsets of hereditary amyloid polyneuropathy (HAP) is unknown. A recent biochemical study of extracted amyloid indicated that in the "portuguese" type of HAP it consists of a prealbumin-related protein. With the use of specific antibodies against human prealbumin, AA, and kappa and lambda type proteins, we demonstrated by indirect immunofluorescence that the amyloid in muscle biopsy specimens from five Americans and one Brazilian with HAP and one Brazilian without a family history (but with typical clinical disease and no plasma cell dyscrasia) was stained exactly and specifically only with antiprealbumin. In contrast, amyloid in muscle biopsy specimens from patients with plasma cell dyscrasic polyneuropathy and in amyloid-negative control muscle biopsy specimens from patients with nonamyloid neuropathies did not bind antiprealbumin antibodies. Our findings suggest that prealbumin-like protein may be a commonality of amyloid deposits in many, and possibly all, subsets of HAP.