Hereditary amyloidosis: evidence against early amyloid deposition.

Twelve members of the Indiana hereditary amyloidosis type II kindred were tested for the presence of amyloid deposits. All were young adults (age 26-37), with no evidence of disease and with 1 affected parent. Six were found to be carriers of the variant gene, by DNA testing and/or reduced serum retinol-binding protein levels. Nevertheless, no amyloid could be found in any skin, rectal, or carpal tunnel biopsy specimens. Our results suggest that hereditary amyloidosis type II is a true late-onset disease, in which accumulation of amyloid does not start until late in life--perhaps only a short time before symptoms appear.