The protein has a molecular weight of 11,800 and is normally filtered by the kidney. Its increased concentration in the plasma of patients with end-stage renal disease probably accounts for the abnormal deposition of amyloid. The nephrotic syndrome is a serious, relatively common complication of the disease. Lower limb neuropathy is a common finding in this form of amyloidosis. This condition, termed senile amyloidosis, is presumed to be an incidental finding, but the deposits may have caused organ dysfunction during life.
Some authors caution against liver biopsy because of the danger of hepatic rupture and hemorrhage.
If involved tissues are not easily accessible, a rectal biopsy, which reportedly yields the correct diagnosis in about 80 percent of cases, can be done. In 50 percent of cases, the diagnosis is apparent on examination of skin biopsy specimens. Marrow biopsy samples and rectal and subcutaneous fat-pad biopsies, when appropriately stained with Congo red, occasionally can also provide the diagnosis. Deposits of amyloid in the hemodialysis-associated variant can also be visualized by this technique. This procedure, however, is not widely available in hospitals.