A study of the neuropathy associated with transthyretin amyloidosis (ATTR) in the UK.

BACKGROUND: Hereditary transthyretin amyloidosis (ATTR) is usually characterised by a progressive peripheral and autonomic neuropathy often with associated cardiac failure and is due to dominantly inherited transthyretin mutations causing accelerated amyloid deposition. The UK population is unique in that the majority of patients have the T60A missense mutation in ATTR where tyrosine is replaced by adenine at position 60. This has been traced to a single founder mutation from north-west Ireland. The neuropathy phenotype is less well described than the cardiac manifestations in this group. METHODS: We present the findings from an observational cohort study of patients with ATTR attending the National Hospital Inherited Neuropathy Clinic between 2009 and 2013. Detailed clinical neurological and electrophysiological data were collected on all patients alongside correlating autonomic and cardiac assessments. Follow-up data were available on a subset. RESULTS: Forty-four patients with genetically confirmed ATTR were assessed; 37 were symptomatic; mean age at onset=62 years, range=38-75 years; 75.7% male. T60A was the most common mutation (17/37), followed by V30M (5/37). A severe, rapidly progressive, predominantly length dependent axonal sensorimotor neuropathy was the predominant phenotype. T60A patients were distinguished by earlier and more frequent association with carpal tunnel syndrome; a predominance of negative sensory symptoms at onset; significant vibration deficits; and a non-length dependent progression of motor deficit. Progression of the neuropathy was observed over a relatively short follow-up period (2 years) in 20 patients with evidence of clinically measurable annual change in Medical Research Council (MRC) sum score (-1.5 points per year) and Charcot Marie Tooth Neuropathy Score (CMTNS:2.7 points per year), and a congruent trend in the electrophysiological measures used. CONCLUSION: The description of the ATTR neuropathy phenotype, especially in the T60A patients, should aid early diagnosis as well as contribute to the understanding of its natural history.

Renal transplantation in systemic amyloidosis-importance of amyloid fibril type and precursor protein abundance.

Renal transplantation remains contentious in patients with systemic amyloidosis due to the risk of graft loss from recurrent amyloid and progressive disease. Outcomes were sought among all patients attending the UK National Amyloidosis Centre who received a renal transplant (RTx) between January 1978 and May 2011. A total of 111 RTx were performed in 104 patients. Eighty-nine percent of patients with end-stage renal disease (ESRD) due to hereditary lysozyme and apolipoprotein A-I amyloidosis received a RTx. Outcomes following RTx were generally excellent in these diseases, reflecting their slow natural history; median graft survival was 13.1 years. Only 20% of patients with ESRD due to AA, AL and fibrinogen amyloidosis received a RTx. Median graft survival was 10.3, 5.8 and 7.3 years in these diseases respectively, and outcomes were influenced by fibril precursor protein supply. Patient survival in AL amyloidosis was 8.9 years among those who had achieved at least a partial clonal response compared to 5.2 years among those who had no response (p = 0.02). Post-RTx chemotherapy was administered successfully to four AL patients. RTx outcome is influenced by amyloid type. Suppression of the fibril precursor protein is desirable in the amyloidoses that have a rapid natural history.

Hereditary lysozyme amyloidosis -- phenotypic heterogeneity and the role of solid organ transplantation.

OBJECTIVES: Lysozyme amyloidosis (ALys) is a form of hereditary systemic non-neuropathic amyloidosis, which is inherited in an autosomal dominant fashion. Lysozyme, which is the amyloidogenic precursor protein in ALys, is a ubiquitous bacteriolytic enzyme synthesized by hepatocytes, polymorphs and macrophages. The aim of this study is to describe the phenotype and outcome of patients with ALys including the role of solid organ transplantation. DESIGN: Retrospective evaluation of patients with ALys. SETTING: UK National Amyloidosis Centre. PATIENTS: All 16 patients with ALys followed at the centre. RESULTS: A family history of amyloidosis was present in every affected individual. Although the phenotype was broadly similar amongst those from the same kindred, there were marked phenotypic differences between kindreds who possessed the same amyloidogenic mutation. Symptomatic gastrointestinal (GI) amyloid was prevalent, and macroscopically visible amyloidotic lesions were present in nine of 10 patients who underwent GI endoscopy. All symptomatic ALys individuals had hepatic amyloid. Four patients received orthotopic liver transplants (OLT), three for spontaneous hepatic rupture and one case, who had extensive hepatic amyloid and a strong family history of hepatic rupture, pre-emptively. All of the liver grafts were functioning at censor 1.7, 5.8, 9.0 and 11.0 years after OLT. Five patients had progressive amyloidotic renal dysfunction culminating in end-stage renal failure, three of whom underwent renal transplantation (RTx). There was no evidence of renal allograft dysfunction at censor 6.6, 1.8 and 0.8 years after RTx. CONCLUSIONS: Lysozyme amyloidosis is a disease of the GI tract, liver and kidneys, which has a slow natural history. There was a clear family history in all cases within this cohort, demonstrating a high clinical penetrance in the presence of an amyloidogenic lysozyme mutation. There is currently no amyloid-specific therapy for the condition which is managed symptomatically. OLT and RTx appear to be successful treatments for patients with liver rupture or end-stage renal disease, respectively, with excellent outcomes in terms of medium-term graft function and patient survival.

Solid organ transplantation in AL amyloidosis.

Vital organ failure remains common in AL amyloidosis. Solid organ transplantation is contentious because of the multisystem nature of this disease and risk of recurrence in the graft. We report outcome among all AL patients evaluated at the UK National Amyloidosis Centre who received solid organ transplants between 1984 and 2009. Renal, cardiac and liver transplants were performed in 22, 14 and 9 patients respectively, representing <2% of all AL patients assessed during the period. One and 5-year patient survival was 95% and 67% among kidney recipients, 86% and 45% among heart recipients and 33% and 22% among liver recipients. No renal graft failed due to recurrent amyloid during median (range) follow up of 4.8 (0.2-13.3) years. Median patient survival was 9.7 years among 8/14 cardiac transplant recipients who underwent subsequent stem cell transplantation (SCT) and 3.4 years in six patients who did not undergo SCT (p = 0.01). Amyloid was widespread in all liver transplant recipients. Solid organ transplantation has rarely been performed in AL amyloidosis, but these findings demonstrate feasibility and support a role in selected patients.

Spinal Stenosis in Familial Transthyretin Amyloidosis.

Here we describe a patient with genetically confirmed ATTR, a family history of the disease and histological confirmation following carpal tunnel release surgery but no other manifestations. The first major neurological or systemic manifestation was cauda equina syndrome with ATTR deposits contributing to lumbar spinal stenosis. Recent gene therapy trials showed improvement in the neuropathy in TTR amyloidosis. This case highlights the need for awareness of the heterogeneous neurological phenotype seen in ATTR to aid earlier diagnosis especially now that disease modifying therapies are available.

Measurement of liver and spleen interstitial volume in patients with systemic amyloid light-chain amyloidosis using equilibrium contrast CT.

OBJECTIVES: To investigate equilibrium contrast-enhanced CT (EQ-CT) measurement of extracellular volume fraction (ECV) in patients with systemic amyloid light-chain (AL) amyloidosis, testing the hypothesis that ECV becomes elevated in the liver and spleen and ECV correlates with other estimates of organ amyloid burden. METHODS: 26 patients with AL amyloidosis underwent EQ-CT, and ECV was measured in the liver and spleen. Patients also underwent serum amyloid P (SAP) component scintigraphy with grading of liver and spleen involvement. Mann-Whitney U test was used to test for a difference between patients with amyloid deposition (SAP grade 1-3) and those without (SAP grade 0). Variation in ECV across SAP grades was assessed using the Kruskal-Wallis test and association between ECV and SAP grades with Spearman correlation. RESULTS: Mean ECV in the spleen and liver was significantly greater (p < 0.0005) in amyloidotic organs (SAP grade 1-3) [spleen, liver: 0.430, 0.375] compared with healthy tissues [spleen, liver: 0.304, 0.269]. ECV increased with increasing amyloid burden, showing positive correlation with SAP grade in both the liver (r = 0.758) and spleen (r = 0.867). CONCLUSION: In patients with systemic AL amyloidosis, EQ-CT can demonstrate increased spleen and liver ECV, which is associated with amyloid disease burden.

Renal amyloidosis in intravenous drug users.

BACKGROUND: Intravenous drug abuse is associated with a wide variety of acute and chronic medical complications. The increased longevity of drug users has seen the emergence of new diseases as a result of chronic bacterial and viral infection. We recently observed an increase in the number of cases of renal amyloidosis among intravenous drug users in central London. AIM: To describe here the demographic and clinical characteristics of such patients. METHODS: Patients were identified retrospectively from computerized patient renal biopsy records at University College London and Royal Free Hospitals from 1990-2005. Clinical information was collected from patient hospital records. RESULTS: We identified 20 cases of AA amyloidosis; 65% occurred between January 2000 and September 2005. All were proteinuric (mean 7.3 g/l, range 0.5-14.8 g/l) and 13 required dialysis within 1 month of diagnosis. Of the remaining seven, four developed end-stage renal failure after mean follow-up of 16 months (range 6-30). Nine died, with median survival of 19 months (range 1-62); all deaths were due to sepsis. DISCUSSION: Secondary AA amyloidosis is a serious complication of chronic soft tissue infection in intravenous drug users in central London. Affected individuals invariably presented with nephrotic range proteinuria and advanced renal failure. Treatment options are limited and the outcome for such patients on renal replacement was poor. Cross-disciplinary strategies are needed to prevent this serious complication of long-term intravenous drug abuse.

Transthyretin V122I amyloidosis with clinical and histological evidence of amyloid neuropathy and myopathy.

Hereditary transthyretin amyloidosis (ATTR) is a genetically and clinically heterogeneous disease manifesting with predominant peripheral and autonomic neuropathy; cardiomyopathy, or both. ATTR V122I is the most common variant associated with non-neuropathic familial amyloid cardiomyopathy. We present an unusual case of V122I amyloidosis with features of amyloid neuropathy and myopathy, supported by histological confirmation in both sites and diffuse tracer uptake on (99m)Tc-3,3-Diphosphono-1,2-Propanodicarboxylic acid (DPD) scintigraphy throughout skeletal and cardiac muscle. A 64 year old Jamaican man presented with cardiac failure. Cardiac MR revealed infiltrative cardiomyopathy; abdominal fat aspirate confirmed the presence of amyloid, and he was homozygous for the V122I variant of transthyretin. He also described general weakness and EMG demonstrated myopathic features. Sural nerve and vastus lateralis biopsy showed TTR amyloid. The patient is being treated with diflunisal, an oral TTR stabilising agent. Symptomatic myopathy and neuropathy with confirmation of tissue amyloid deposition has not previously been described. Extracardiac amyloidosis has implications for diagnosis and treatment.

Oculoleptomeningeal Amyloidosis associated with transthyretin Leu12Pro in an African patient.

Oculoleptomeningeal amyloidosis is a rare manifestation of hereditary transthyretin (TTR) amyloidosis. Here, we present the first case of leptomeningeal amyloidosis associated with the TTR variant Leu12Pro mutation in an African patient. A 43-year-old right-handed Nigerian man was referred to our centre with rapidly progressive neurological decline. He presented initially with weight loss, confusion, fatigue, and urinary and erectile dysfunction. He then suffered recurrent episodes of slurred speech with right-sided weakness. He went on to develop hearing difficulties and painless paraesthesia. Neurological examination revealed horizontal gaze-evoked nystagmus, brisk jaw jerk, increased tone, brisk reflexes throughout and bilateral heel-shin ataxia. Magnetic resonance imaging showed extensive leptomeningeal enhancement. Cerebrospinal fluid analysis showed a raised protein of 6.4 g/dl. Nerve conduction studies showed an axonal neuropathy. Echocardiography was characteristic of cardiac amyloid. TTR gene sequencing showed that he was heterozygous for the leucine 12 proline mutation. Meningeal and brain biopsy confirmed widespread amyloid angiopathy. TTR amyloidosis is a rare cause of leptomeningeal enhancement, but should be considered if there is evidence of peripheral or autonomic neuropathy with cardiac or ocular involvement. The relationship between different TTR mutations and clinical phenotype, disease course, and response to treatment remains unclear.

Clinical and biochemical outcome of hepatorenal transplantation for hereditary systemic amyloidosis associated with apolipoprotein AI Gly26Arg.

BACKGROUND: Treatment of systemic amyloidosis comprises measures to support failing organ function coupled with attempts to reduce the supply of the respective amyloid fibril precursor protein. Orthotopic hepatic transplantation is effective in familial amyloid polyneuropathy associated with variant transthyretin, because this protein is produced almost exclusively in the liver. Hepatic transplantation has not been performed in hereditary apolipoprotein AI (apoAI) amyloidosis, and the liver's contribution to plasma apoAI levels has not been determined in vivo. METHODS: A 57-year-old Irish man with hereditary systemic amyloidosis associated with apoAI Gly26Arg, which had led to end-stage renal failure and progressive liver dysfunction, underwent hepatorenal transplantation. His outcome was followed clinically and his amyloid deposits were monitored with serum amyloid P component scintigraphy. The proportion of variant apoAI in the plasma was estimated by quantitative isoelectric focusing before and after liver transplantation. RESULTS: Plasma levels of variant apoAI decreased by 50% after liver transplantation, and the patient was asymptomatic 2 years after surgery. Subclinical amyloid deposits that were present in his spleen and heart preoperatively have regressed and stabilized respectively. CONCLUSIONS: Orthotopic liver transplantation substantially reduces the supply of the amyloid fibril precursor protein in hereditary apoAI amyloidosis, and the excellent outcome in this patient probably reflects the balance between deposition and turnover of amyloid having been altered in favor of the latter. These findings support the use of liver transplantation in patients with hereditary apoAI amyloidosis who develop hepatic dysfunction.

SAA1 alleles as risk factors in reactive systemic AA amyloidosis.

SAA1 is the predominant isoform of acute phase human SAA deposited as AA amyloid fibrils in reactive systemic amyloidosis. It has recently been reported that in the Japanese population, in whom the SAA1 gamma allele occurs with a frequency of 37%, possession of, and especially, homozygosity for this allele is a significant risk factor for AA amyloidosis in adult patients with rheumatoid arthritis (RA). In contrast we report here that in a control sample of 95 healthy adult male Caucasians the SAA1 gamma allele occurs at the much lower frequency of 5.3% and that, among 41 patients with juvenile chronic arthritis (JCA) and AA amyloidosis, there was a highly significantly increased frequency of the SAA1 alpha allele (90.2%), and particularly homozygosity for this allele (80.5%), compared both to the healthy controls (75.8% and 57.9% respectively) and to 8 JCA cases without amyloid (56.3% and 12.5%). A similar trend with respect to frequency of the SAA1 alpha allele and homozygosity for it was observed among 26 adult Caucasian RA patients with AA amyloid and 26 such cases without amyloid, although it did not reach statistical significance. These results suggest that there is probably differential amyloidogenicity amongst the different SAA1 isoforms and indicate that homozygosity for SAA1 alpha and SAA1 gamma in the different populations is a significant risk factor for development of AA amyloidosis. In Caucasian patients with JCA, the presence of the homozygous SAA1 alpha genotype indicates high risk of amyloidosis and should encourage early and aggressive anti-inflammatory therapy to keep circulating SAA levels as low as possible.

Prevalence and significance of the familial Mediterranean fever gene mutation encoding pyrin Q148.

Familial Mediterranean fever (FMF) is caused by more than 25 mutations in the gene MEFV, which encodes pyrin (marenostrin), a protein implicated in the regulation of neutrophil activity. Pyrin Q148, is one of the five most common variants in populations in which FMF typically occurs. Our identification of the pyrin Q148 allele in several patients from ethnic groups in which FMF is not classically recognized who had longstanding fevers or AA amyloidosis prompted us to study the prevalence of pyrin Q148 in healthy British, Indian and Chinese subjects. The gene frequency was also sought in 50 British Caucasian patients with inflammatory arthritis, 25 of whom had AA amyloidosis, five Punjabi Indians with AA amyloidosis complicating inflammatory arthritis, and seven British Caucasian patients with uncharacterized longstanding fever syndromes. The allele frequency for pyrin Q148 was 21%, 15% and 0%, respectively, among Punjabi Indian, Chinese and Caucasian British controls, and was significantly increased among the patients with AA amyloidosis and the patients with obscure fever syndromes (p<0.01). Pyrin Q148 is a polymorphism and occurs widely in global terms, and, although it may cause FMF when associated with certain other MEFV mutations, homozygosity for Q148 alone must usually be insufficient to produce FMF in the populations studied. The association of pyrin Q148 with AA amyloidosis and with obscure chronic inflammatory diseases suggests the variant may augment inflammation non-specifically, which might have been beneficial during evolution, but could potentially exacerbate many chronic inflammatory disorders.

Unicentric Castleman's disease complicated by systemic AA amyloidosis: a curable disease.

BACKGROUND: Castleman's disease (angiofollicular lymph node hyperplasia) is a group of rare lymphoproliferative disorders sharing characteristic clinical and histological features, and usually accompanied by a marked systemic inflammatory response. All types may be complicated by acquired systemic amyloidosis, usually of AA type, but occasionally of AL type associated with monoclonal gammopathy. DESIGN: Descriptive study of five patients with unicentric Castleman's disease complicated by systemic AA amyloidosis. METHODS: A diagnosis of amyloidosis was confirmed by microscopy and immunohistochemical staining. Serum concentrations of C-reactive protein (CRP) and serum amyloid A protein (SAA) were measured by immunoassays. Radiolabelled serum amyloid P component scintigraphy was used to monitor the progress of amyloid deposition. RESULTS: In four patients the primary diagnosis was made only after years of investigation of systemic symptoms. The tumours were resected in all cases, leading to remission of the systemic inflammatory state. Long-term follow-up in four patients, including scintigraphy, showed regression of amyloid deposits. DISCUSSION: This rare but usually fatal condition can be cured surgically even in advanced cases. Awareness of the diagnosis and its correct management are important in investigation of patients with unexplained systemic symptoms, especially associated with systemic amyloidosis.

Pyrin/marenostrin mutations in familial Mediterranean fever.

Familial Mediterranean fever (FMF) is an inherited inflammatory disease that is frequently complicated by reactive systemic (AA) amyloidosis. It is principally recognized in certain Mediterranean populations, and the diagnosis depends on clinical features. Four mutations strongly linked to FMF have lately been identified in a gene encoding a novel protein that has been named pyrin or marenostrin. We studied 27 consecutive patients of varied ethnic origin, including an English man, who had classical, probable or possible FMF. Pyrin/marenostrin genotypes were determined, and AA amyloidosis was sought using serum amyloid P component scintigraphy. Among the 23 patients with classical or probable FMF, 17 were homozygotes or compound heterozygotes for pyrin/marenostrin mutations, and in five, only single allele mutations were identified. Two new mutations, T6811 and delta M694, were discovered in addition to the four described previously. No mutations were identified in three of the four patients with possible FMF. Nine patients had AA amyloidosis, but this association was not restricted to any particular genotype. Most patients with FMF have mutations in both pyrin/marenostrin alleles, and genotyping at this locus is a valuable diagnostic test. Unidentified second mutations are likely to occur in FMF patients who have apparently solitary mutations, and therefore genotype results must be interpreted in conjunction with the clinical picture.

Curative hepatorenal transplantation in systemic amyloidosis caused by the Glu526Val fibrinogen alpha-chain variant in an English family.

A 53-year-old English woman who had been thought to have systemic monoclonal immunoglobulin light chain (AL) amyloidosis was investigated further because of her unusually long 17-year history and a suggestion of renal disease in the family. She was found to have the Glu526Val fibrinogen alpha-chain variant that causes autosomal dominant hereditary systemic amyloidosis. This has not previously been described in a British family. The mutant gene was associated with the same haplotype as in all other reported cases, suggesting a common founder. The patient had already received a renal transplant, but the graft failed within 6 years due to amyloid deposition. Progressive hepatic amyloidosis eventually caused liver failure, although the function of other organs was well preserved. She therefore received hepatic and renal transplants to replace the failed organs and the hepatic source of the amyloidogenic variant fibrinogen. Three years later she is completely well and has no amyloid deposits identifiable by serum amyloid P component scintigraphy. This is the first detailed report of hepatic transplantation for liver failure caused by amyloidosis of any type. The substantial follow-up suggests that fibrinogen alpha-chain amyloidosis is one of the inherited metabolic diseases that can be cured by liver transplantation. The mutation underlying Glu526Val fibrinogen alpha-chain amyloidosis is incompletely penetrant and has a variable phenotype that can clinically mimic AL amyloidosis. Hereditary fibrinogen amyloidosis may be more prevalent than previously suspected and, since AL amyloid is sometimes a diagnosis of exclusion, genotyping for other amyloidogenic proteins is mandatory in all cases in which the amyloid fibrils cannot be positively identified as AL.

The genetic basis of autosomal dominant familial Mediterranean fever.

Familial Mediterranean fever (FMF) is classically an autosomal recessive periodic inflammatory disease occurring in Mediterranean and Middle Eastern populations. It is caused by mutations affecting both alleles of MEFV, a gene that encodes pyrin (marenostrin), an uncharacterized neutrophil protein. Occasional reports of autosomal dominant FMF have often been discounted, on the basis that asymptomatic FMF carriers are common in certain populations, and give rise to pseudo-dominant inheritance. We performed comprehensive MEFV genotyping in five families in whom FMF appeared to be inherited dominantly. Transmission proved to be pseudo-dominant in two cases, but true dominant inheritance of FMF with variable penetrance was supported by the genotyping results in the other three families. The disease in these cases was associated with heterozygosity for either pyrin DeltaM694 alone or the compound pyrin variant E148Q/M694I, the latter occurring in two unrelated families. Complete MEFV sequencing failed to identify any coding region abnormality in the other allele in any of these cases, and, in the largest kindred, single-allele disease transmission was further supported by analysis of silent single nucleotide polymorphisms, which proved that affected individuals had at least three different complementary alleles. Studies of two further unrelated British patients with FMF associated with simple heterozygosity for pyrin DeltaM694 were also consistent with autosomal dominant inheritance. The clinical features of dominantly inherited FMF were absolutely typical, including AA amyloidosis in a patient with pyrin DeltaM694. These findings extend the spectrum of FMF, and suggest that the methionine residue at position 694 makes a crucial contribution to pyrin's function, and that a 50% complement of normal pyrin activity does not prevent susceptibility to FMF.

Expression of capsules by Haemophilus influenzae in mixed infections.

The pathogenicity of eight clinical isolates of non-type b Haemophilus influenzae was investigated by inoculating them subcutaneously into mice, alone or mixed with viable or non-viable bacteria of certain other species. Three of the H. influenzae isolates were non-capsulated while five were slightly capsulated (less than 1% of organisms had capsules). The other strains of bacteria tested were four isolates of capsulated and four isolates of non-capsulated pigmented strains of Prevotella sp. and Porphyromonus sp. as well as a capsulate Klebsiella pneumoniae ("helpers"). None of the non-capsulated strains induced an abscess when inoculated alone. Following co-inoculation of viable or non-viable "helpers" with H. influenzae, abscesses were formed in all instances in which the "helper" had a capsule. Profusely capsulated cells of H. influenzae were recovered, however, only from abscesses induced with the five slightly capsulated strains of H. influenzae. These capsulated organisms were found serologically to be of type b and induced abscesses when inoculated alone. Our findings illustrate the ability of non-capsulated strains of H. influenzae to produce progeny of capsulated type b organisms after co-inoculation with certain other species.