A rare, systemic amyloidosis characterized by slowly progressive renal dysfunction, increased serum creatinine, mostly normal urine analysis with no significant proteinuria and associated heart disease. Cardiac involvement presents as hypertrophic obstructive cardiomyopathy, left ventricular outflow tract obstruction, coronary artery disease and conduction system abnormalities. Histology reveals renal tubular atrophy, interstitial fibrosis, glomerular sclerosis, and medullar amyloid deposits.

The presence of renal tubules with thick redundant basement membranes, or a reduction of greater than 50% in tubular diameter compared to surrounding non-atrophic tubules.