No abstract

Three members of a family who died with renal amyloidosis were found to share a single nucleotide substitution in the fibrinogen alpha-chain gene. The predicted arginine to leucine mutation (Arg554Leu) was proven by amino acid sequence analysis of amyloid fibril protein isolated from postmortem kidney of an affected individual. Direct genomic DNA sequencing and restriction fragment length polymorphism analysis demonstrated that all three affected individuals had the guanine to thymine 4993 transversion. This is the first demonstration of hereditary amyloidosis associated with a variant fibrinogen alpha-chain. Variants of circulating fibrinogen may be the cause of a number of systemic amyloidoses with primarily renal involvement.

Two families with hereditary renal amyloidosis were found to have a novel mutation in the fibrinogen Aa chain gene. This form of amyloidosis is an autosomal dominant condition characterized by proteinuria, hypertension, and subsequent azotemia.DNAs of patients with amyloidosis were screened for a polymorphism in fibrinogen Aa chain gene by single-strand conformation polymorphism analysis, and affected individuals from two kindreds were found to have a mutation. Both of these kindreds are American of Irish descent presenting with nonneuropathic, nephropathic amyloidosis in the fifth to the seventh decade of life. DNA sequencing showed a point mutation in the fibrinogen Aa chain gene that is responsible for substitution of valine for glutamic acid at position 526. By restriction fragment length polymorphism analysis, 7 affected individuals and 14 asymptomatic individuals in these two kindreds were positive for the fibrinogen Aa chain Val 526 gene. Fibrinogen was isolated from plasma of a heterozygous gene carrier and shown to contain -50% variant fibrinogen.Discovery of this new mutation confirms the association between fibrinogen Aa chain variant and hereditary renal amyloidosis and establishes a new biochemical subtype of amyloidosis. (J. Clin. Invest. 1994. 93:731-736.)

In this kindred, oculoleptomeningeal amyloidosis is related to a mutation in transthyretin (Phe64Ser).

Autosomal dominant hereditary amyloidosis with a unique cutaneous and cardiac presentation and death from heart failure by the sixth or seventh decade was found to be associated with a previously unreported point mutation (thymine to cytosine , nt 1389) in exon 4 of the apolipoprotein A1 (apoA1) gene. The predicted substitution of proline for leucine at amino acid position 90 was confirmed by structural analysis of amyloid protein isolated from cardiac deposits of amyloid. The subunit protein is composed exclusively of NH 2 -terminal fragments of the variant apoA1 with the longest ending at residue 94 in the wild-type sequence. Amyloid fibrils derived from four previously described apoA1 variants are composed of similar fragments with carboxyl-terminal heterogeneity, but contrary to those variants , which all carry one extra positive charge , the substitution Leu90Pro does not result in any charge modification. It is unlikely , therefore , that amyloid fibril formation is related to change of charge for a specific residue of the precursor protein. This is in agreement with studies on transthyretin amyloidosis in which no unifying factor such as change of charge for amino acid residues has been noted. (Am J Pathol 1999, 154:221-227)

A new American kindred with amyloidosis was found by single-strand conformation polymorphism analysis to have a mutation in the fibrinogen A alpha chain gene. Affected members in this kindred have autosomal dominant amyloid nephropathy. DNA sequencing showed a single nucleotide deletion at the third base of codon 524 of the fibrinogen A alpha chain genes (4904delG) that resulted in a frame shift and premature termination of the protein at codon 548. Antiserum was produced to a portion of the abnormal peptide predicted by the DNA sequence and amyloid deposits were immuno-histologically proven to contain this abnormal peptide. Two of the propositus' 4 children were positive for the mutant fibrinogen A alpha chain gene by restriction fragment length polymorphism analysis based on polymerase chain reaction. These two mutant gene carriers now in the second decade of life show no clinical symptoms of amyloidosis as yet but have lower plasma fibrinogen concentrations when compared with their normal siblings. This the first description of a kindred with renal amyloidosis and low plasma fibrinogen and also the first report of amyloidosis caused by a frame shift mutation.

No abstract

Systemic amyloidosis results from the deposition of insoluble protein fibrils in various organs and tissues. To date, several different proteins have been associated with amyloid fibril formation, including immunoglobulin light chain, serum amyloid A protein, and transthyretin. Recent reports have shown that variant fibrinogen chains can form amyloid in certain kindreds. Hepatic transplantation has previously been reported in the treatment of hereditary amyloidosis associated with variant transthyretin proteins, which are mainly synthesized in the liver. This article reports the first use and long-term follow-up of combined hepatic and renal transplantation in the successful treatment of two patients with hereditary fibrinogen amyloidosis. Both patients experienced sustained improvement in renal function and nutritional status at 61/2 years and 28 months of follow-up, respectively. Orthotopic liver transplantation is effective and potentially curative treatment of hereditary fibrinogen amyloidosis.