1/8. Identification of a novel transthyretin Thr59Lys/Arg104His. A case of compound heterozygosity in a Chinese patient diagnosed with familial transthyretin amyloidosis.Transthyretin (TTR) is a 127-amino acid residue protein synthesized mainly in the liver and in several minor sites, including the choroid plexus and the eye. In plasma, TTR circulates as a homotetramer and transports the hormone thyroxine and the retinol-binding protein-vitamin a complex. It is hypothesized that amino acid substitutions in TTR destabilize the tetramer by causing each subunit toform intermediates that may self-associate into amyloid fibrils. Deposition of wild type TTR, its variants and/or fragments as amyloid fibrils in tissues and organs is associated with familial transthyretin amyloidosis (ATTR). Reported herein is the characterization of a novel TTR Thr59Lys/Arg104His in a patient of Chinese ancestry, who was diagnosed with ATTR. The two variant proteins and the double gene mutations in this compound heterozygous case were detected and identified using a multifaceted approach consisting of isoelectric focusing, electrospray ionization mass spectrometry (MS), matrix-assisted laser desorption/ionization time-of-flight MS in combination with enzymatic digestion, and direct dna sequence analysis. Previous studies have shown that the TTR Arg104His variant is non-pathologic. It appeared to provide a protective effect in another compound heterozygous case (TTR Val30Met/Arg104His). However, the TTR Arg104His variant when presented with the TTR Thr59Lys variant did not seem to have any protective role.- - - - - - - - - - ranking = 1keywords = organ (Clic here for more details about this article) |
2/8. Orthotopic liver transplantation for hereditary fibrinogen amyloidosis.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.- - - - - - - - - - ranking = 1keywords = organ (Clic here for more details about this article) |
3/8. Identification of S-sulfonation and S-thiolation of a novel transthyretin Phe33Cys variant from a patient diagnosed with familial transthyretin amyloidosis.Familial transthyretin amyloidosis (ATTR) is an autosomal dominant disorder associated with a variant form of the plasma carrier protein transthyretin (TTR). Amyloid fibrils consisting of variant TTR, wild-type TTR, and TTR fragments deposit in tissues and organs. The diagnosis of ATTR relies on the identification of pathologic TTR variants in plasma of symptomatic individuals who have biopsy proven amyloid disease. Previously, we have developed a mass spectrometry-based approach, in combination with direct dna sequence analysis, to fully identify TTR variants. Our methodology uses immunoprecipitation to isolate TTR from serum, and electrospray ionization and matrix-assisted laser desorption/ionization mass spectrometry (MS) peptide mapping to identify TTR variants and posttranslational modifications. Unambiguous identification of the amino acid substitution is performed using tandem MS (MS/MS) analysis and confirmed by direct dna sequence analysis. The MS and MS/MS analyses also yield information about posttranslational modifications. Using this approach, we have recently identified a novel pathologic TTR variant. This variant has an amino acid substitution (Phe --> Cys) at position 33. In addition, like the Cys10 present in the wild type and in this variant, the Cys33 residue was both S-sulfonated and S-thiolated (conjugated to cysteine, cysteinylglycine, and glutathione). These adducts may play a role in the TTR fibrillogenesis.- - - - - - - - - - ranking = 1keywords = organ (Clic here for more details about this article) |
4/8. Two different types of amyloid deposits--apolipoprotein A-IV and transthyretin--in a patient with systemic amyloidosis.Certain forms of systemic amyloidosis have been associated with the pathologic deposition as fibrils of three different apolipoprotein-related proteins--apolipoprotein A-I, apolipoprotein a-ii, and serum amyloid A. We have previously reported (Bergstrom et al, Biochem Biophys Res Commun 2001;285:903-908) that amyloid fibrils extracted from the heart of an elderly male with senile systemic amyloidosis contained, in addition to wild-type transthyretin-related molecules, an N-terminal fragment of yet a fourth apolipoprotein--apolipoprotein A-IV (apoA-IV). We now provide the results of our studies that have established the complete amino-acid sequence of this approximately 70-residue component and, additionally, have shown this protein to be the product of an unmutated apoA-IV gene. Notably, the apoA-IV and transthyretin fibrils were not codeposited but, rather, had anatomically distinct patterns of distribution within the heart and other organs, as evidenced immunohistochemically, by variation in the ultra structural morphology and by differences in the intensity of congo red birefringence. These findings provide the first conclusive evidence that two separate forms of amyloid, each derived from a wild-type amyloidogenic precursor protein, were present in a patient with systemic amyloidosis.- - - - - - - - - - ranking = 1keywords = organ (Clic here for more details about this article) |
5/8. Mutant fibrinogen A-alpha-chain associated with hereditary renal amyloidosis and peripheral neuropathy.A middle age Portuguese woman was investigated for renal amyloidosis. She presented with progressive renal failure, proteinuria, hypertension, and sensory symptoms in the feet. Clinical and neurophysiological evaluation disclosed sensory-autonomic neuropathy. Cardiovascular tests and 123-MIBG investigation showed parasympathetic dysfunction and decrease of myocardial innervation, in accordance with small fiber neuropathy, as usually observed in amyloidosis. Immunohistochemical studies revealed AFib amyloidosis and genetic studies the amino acid exchange Glu526Val of the fibrinogen Aalpha-chain mutation, which was also present in one of her sons. The mutant gene in this patient was associated with the same haplotype as all other reported cases of Glu526Val mutations. This is the first reported AFibamyloidosis in portugal, and the first case of AFib in which sensory and autonomic nerve fiber dysfunction is described, indicating that small nerve fiber lesion can occur in the fibrinogen Aalpha chain mutation. This can be important for prognosis, in particular when liver transplantation is considered for treatment.- - - - - - - - - - ranking = 1.1450269947014keywords = nerve (Clic here for more details about this article) |
6/8. Renal apolipoprotein A-I amyloidosis associated with a novel mutant Leu64Pro.Apolipoprotein A-I amyloidosis (Apo A-I) is an inherited systemic disease that results from the pathologic deposition in tissues throughout the body of fibrils composed of Apo A-I-related molecules. This disorder has been linked to mutations occurring within the coding region of the Apo A-I gene and, to date, 11 such substitutions have been documented. In 4 of these cases, the kidney was the target organ of the disease process. The authors report their studies on a patient with renal amyloidosis and a heretofore undescribed alteration in the amyloidogenic precursor protein. Analyses of genomic dna evidenced a transition in the second base of codon 64 (T-->C) in one Apo A-I allele that resulted in the replacement of leucine by proline at position 64 (Leu64Pro). Additionally, fibrils extracted from the kidney and characterized chemically were found to be composed almost exclusively of an approximately 96-residue N-terminal Apo A-I fragment that contained the Leu64Pro substitution. These studies have provided further evidence for Apo A-I amyloidogenicity and the propensity of certain mutants to deposit in renal parenchyma.- - - - - - - - - - ranking = 1keywords = organ (Clic here for more details about this article) |
7/8. Two familial cases with tumor necrosis factor receptor-associated periodic syndrome caused by a non-cysteine mutation (T50M) in the TNFRSF1A gene associated with severe multiorganic amyloidosis.An adolescent boy had had recurrent episodes of fever, abdominal pain, and arthralgias since the age of 7 years. Progressive renal failure due to renal amyloidosis developed, leading to renal transplant at the age of 14.5 years. Five years later, he developed AA amyloidosis in the transplant as well as the thyroid gland. His father had had similar symptoms including systemic amyloidosis since the age of 6 years. dna sequence analysis revealed a heterozygous mutation in the TNFRSF1A (TNFa-receptor 1) gene (T50M) in both father and son causing tumor necrosis factor receptor-associated periodic syndrome (TRAPS). Previous phenotype/genotype analyses have proposed that this mutation is usually not associated with the occurrence of amyloidosis. This difference in the clinical course in different families may indicate a strong influence of modifier genes. Treatment with a TNFRSF1B fusion protein TNF antagonist (etanercept) favorably influenced the disease course.- - - - - - - - - - ranking = 4keywords = organ (Clic here for more details about this article) |
8/8. cutis laxa in hereditary gelsolin amyloidosis.BACKGROUND: Hereditary gelsolin amyloidosis (AGel amyloidosis) is an age-associated systemic disease with global distribution, caused by a G654A or G654T gelsolin gene mutation. cutis laxa is a principal clinical manifestation of this disease. However, only few data on the dermatological involvement are available, and the pathogenesis of this amyloidosis-associated form of cutis laxa has remained unknown. OBJECTIVES: To elucidate the pathomechanism of this less well-known genodermatosis. methods: We performed systematic clinical, histological, immunohistochemical and ultrastructural skin biopsy studies in 12 patients with a G654A gelsolin gene mutation. For comparison, skin specimens from 10 control subjects were analysed. RESULTS: All patients had clinically characteristic cutis laxa, and frequently other signs of symptomatic skin disease such as increased fragility and risk for intracutaneous bleeding. All patients showed cutaneous deposition of gelsolin amyloid (AGel), mainly attached to basement membranes or basal laminae of various cutaneous structures, dermal nerves and blood vessel walls, and elastic fibres, particularly in the lower reticular dermis. AGel often encircled the elastic fibres, and colocalized with amyloid P component (AP), an elastic fibre microfibrillar sheath-associated protein. Fragmentation and loss of elastic fibres, epidermal atrophy, and reduction of dermal appendages were also common. antibodies to wild-type gelsolin bound to S-100-positive epidermal dendritic cells, a previously unrecognized immunoreaction. patients had fewer gelsolin-positive dendritic cells than controls. CONCLUSIONS: Widespread skin involvement with AGel deposition and elastic fibre involvement are essential pathological features in AGel amyloidosis, and contribute to the characteristic cutis laxa, dramatic in old age. Codistribution of AGel and AP, with demonstrated specific binding affinity for amyloid fibrils, suggests that elastic fibre-associated AP acts as a matrix for cutaneous amyloid deposition in AGel amyloidosis.- - - - - - - - - - ranking = 0.57251349735071keywords = nerve (Clic here for more details about this article) |