Renal amyloidosis in related Abyssinian cats.

Renal amyloidosis was diagnosed in 8 related Abyssinian cats. The kidneys were characterized pathologically by medullary interstitial and glomerular amyloid deposition, interstitial fibrosis, and papillary necrosis. Amyloid deposits were birefringent under polarized light after Congo red staining, were thioflavine-T positive, and lost Congo red staining after permanganate oxidation. Four of the cats were evaluated clinically. Two of these cats were terminally uremic, with nonregenerative anemia, azotemia, hyperphosphatemia, metabolic acidosis, mild hyperglycemia, isosthenuria, proteinuria, cylindruria, and mild hematuria. The remaining 2 cats were only moderately azotemic. Three of the cats had severe gingivitis and all 4 cats had hyperproteinemia due to hyperglobulinemia.