Familial amyloid polyneuropathy type I (Portuguese): Distribution and characterization of renal amyloid deposits

Abstract

Renal amyloidosis has been considered rare and late in the evolution of the transthyretin (TTR) familial amyloid polyneuropathy (FAP) of the Portuguese type (type I). Renal biopsy has been performed systematically in 14 patients with FAP type I before liver transplantation. In all patients, TTR Met30 mutation was shown. Seven had proteinuria or abnormal microalbuminuria, whereas seven others had no urinary abnormalities. All had renal amyloid deposition predominantly in the medulla. Glomerular and vascular involvement was more prominent in patients with urinary abnormalities. Patients with the most extensive renal lesions represented a subgroup with a low score of polyneuropathy disability, a high prevalence of nephropathy in the proband generation, or a late onset for relatives with nephropathy. Immunohistochemistry studies showed that the amyloid substance corresponded to transthyretin. We have shown that renal TTR-derived amyloid deposition is common in patients with FAP type I, even in the absence of urinary abnormalities. The clinical presentation of nephropathy is not a late occurrence in the disease. PMID:9631837 [PubMed -indexed for MEDLINE]http://www.ncbi.nlm.nih.gov/pubmed?term=PMID%3A%209631837%20

Pathological characteristics of fifty patients with renal amyloidosis in Sri Lanka

“…In the present study we found that the severity of renal amyloid deposition does not correlate with the severity of renal impairment, which has been shown before [1,2]. However, the degree of renal impairment correlated with severity of glomerulosclerosis which is a secondary effect of amyloidosis induced renal damage.…”

Transthyretin Amyloidosis and the Kidney

“…Proximal tubules positively react with anti-TTR antibody inside the cells, which can be sustained by internalization of TTR by megalin (45,46). Renal dysfunction and the degree of proteinuria are correlated with heavy amyloid deposition in the glomeruli, arterioles, and medium vessels, but not with deposition in medullary tissues (42). Renal deposition does not parallel that of myelinated nerve fiber loss in the sural nerve, suggesting that evolution and severity of nephropathy are not correlated with the degree of neuropathy (21,44,47).…”

“…In one report, in which half the patients studied had normoalbuminuria, amyloid was found in all cases (42). In another report, which involved only 4 patients with proteinuria, 13 of the 14 patients had amyloid deposits (36).…”

Liver transplantation for hereditary transthyretin amyloidosis

“…Kidney amyloidosis is a common finding in FAP, 15,80 although renal impairment is not as common as in secondary (AA) or primary (AL) amyloidosis. However, renal insufficiency has been present in several of our transplant recipients.…”