Recurrent subarachnoid hemorrhage associated with a new transthyretin variant (Gly53Glu)

Hereditary transthyretin amyloidosis: a comprehensive review with a focus on peripheral neuropathy

Amyloidoses represent a group of diseases characterized by the pathological accumulation in the extracellular area of insoluble misfolded protein material called "amyloid". The damage to the tissue organization and the direct toxicity of the amyloidogenic substrates induce progressive dysfunctions in the organs involved. They are usually multisystem diseases involving several vital organs, such as the peripheral nerves, heart, kidneys, gastrointestinal tract, liver, skin, and eyes. Transthyretin amyloidosis (ATTR) is related to abnormalities of transthyretin (TTR), a protein that acts as a transporter of thyroxine and retinol and is produced predominantly in the liver. ATTR is classified as hereditary (ATTRv) and wild type (ATTRwt). ATTRv is a severe systemic disease of adults caused by mutations in the TTR gene and transmitted in an autosomal dominant manner with incomplete penetrance. Some pathogenic variants in TTR are preferentially associated with a neurological phenotype (progressive peripheral sensorimotor polyneuropathy); others are more frequently associated with restrictive heart failure. However, many mutations express a mixed phenotype with neurological and cardiological involvement. ATTRv is now a treatable disease. A timely and definite diagnosis is essential in view of the availability of effective therapies that have revolutionized the management of affected patients. The purpose of this review is to familiarize the clinician with the disease and with the correct diagnostic pathways in order to obtain an early diagnosis and, consequently, the possibility of an adequate treatment.

An Exploratory Study of Cognitive Involvement in Hereditary Transthyretin Amyloidosis

OBJECTIVES

Hereditary amyloidogenic transthyretin (ATTRv) amyloidosis is an autosomal dominant disorder caused by mutations of the transthyretin (TTR) gene. The mutant ATTRv protein causes a systemic accumulation of amyloid fibrils in various organs. TTR is an important protein in the central nervous system physiology for the maintenance of normal cognitive process during aging, amidated neuropeptide processing, and nerve regeneration. The neuroprotective effect of transthyretin has been widely documented in animal models. Cognitive consequences of the mutant TTR in hereditary ATTRv amyloidosis patients remain still to be elucidated. We designed this study to investigate the cognitive involvement in ATTRv amyloidosis.

METHODS

Detailed neuropsychological tests and cranial MRIs were performed. Biomarkers including amyloid beta 1-42, total tau, and phosphorylated tau were investigated in the cerebrospinal fluid samples.

RESULTS

Median age of the cohort was 52 years (ranges 34-72). Neuropsychological assessment results were compatible with impaired executive functions (in all patients except one with only bilateral carpal tunnel syndrome, long-term visual and long-term verbal memory (severe in four patients and moderate in one). Visuospatial judgment and perception were impaired in six. Mean cerebrospinal fluid Aβ1-42 (pg/ml) was 878.0 ± 249.5 in patients with cortical atrophyin MRI whereas 1210.0 ± 45.9 in patients without any cortical atrophy. Cranial MRI showed cortical atrophy in six patients (6/10).

CONCLUSION

Our data showed the significance of the TTR protein in cognitive functions and highlighted the importance of the close follow-up of cognitive functions in ATTRv amyloidosis patients.

CNS Involvement in Hereditary Transthyretin Amyloidosis

Hereditary transthyretin amyloidosis (ATTRv amyloidosis) is predominantly a disease of the peripheral nerves, heart, kidney and eye. CNS involvement has been a marginal issue in research and the clinical setting, until recently. Growing evidence shows that leptomeningeal amyloid accumulation is frequent and present from early stages of ATTRv amyloidosis. Several recent studies show CNS symptoms arise as a common late complication in patients with the V30M mutation, after at least 14 years of symptomatic peripheral nerve disease. Conversely, in non-V30M patients, there are several descriptions, mostly case reports, of patients presenting with severe phenotypes of ocular and CNS dysfunction (oculoleptomeningeal amyloidosis), with little systemic involvement. This phenotype is found in rare families worldwide, associated with at least 14 mutations.In both patients with late and early onset CNS dysfunction, symptoms include transient focal neurological episodes, haemorrhagic and ischemic stroke, cognitive decline and cranial nerve dysfunction. Pathologically, there is severe amyloid deposition in the leptomeninges and cerebral amyloid angiopathy of leptomeningeal and penetrating vessels. These amyloid aggregates are formed mostly by CSF produced TTR and seem resistant to the available ATTRv therapies that increase the stability or reduce the production of plasma TTR. This indicates that CNS involvement will become a meaningful issue in patient management in upcoming years.

Current Review of Leptomeningeal Amyloidosis Associated With Transthyretin Mutations

INTRODUCTION

Leptomeningeal amyloidosis (LA) represents a rare subtype of familial transthyretin (TTR) amyloidosis, characterized by deposition of amyloid in cranial and spinal leptomeninges. Of >120 TTR mutations identified, few have been associated with LA.

CASE REPORT

A 27-year-old male presented with a 2-year history of progressive symptoms including cognitive decline and right-sided weakness and numbness. Cerebrospinal fluid (CSF) analyses demonstrated high protein level. Gadolinium-enhanced magnetic resonance imaging (MRI) revealed extensive leptomeningeal enhancement over the surface of the brain and spinal cord. Pathologic analyses revealed a TTR mutation c.113A>G (p.D38G).

REVIEW SUMMARY

Fifteen mutations and genotype-phenotype correlation of 72 LA patients have been summarized to provide an overview of LA associated with transthyretin mutations. The mean age of clinical onset was 44.9 years and the neurological symptoms primarily included cognitive impairment, headache, ataxia seizures and hearing, visual loss. CSF analysis showed elevated high CSF protein level and MRI revealed extensive leptomeningeal enhancement.

CONCLUSION

Clinicians should be aware of this rare form of familial transthyretin amyloidosis as well as its typical MRI enhancement and high CSF protein. The important role of biopsy, genetic testing and the potential early diagnosis value of contrast MRI were suggested. Early recognition of these characteristics is important to provide misdiagnosis and shorten the time before correct diagnosis. These findings expand the phenotypic spectrum of TTR gene and have implications for the diagnosis, treatment, and systematic study of LA.

Familial Amyloid Polyneuropathy

Transthyretin-related familial amyloid polyneuropathy (TTR-FAP) is a life-threatening disease caused by the accumulation of amyloidogenic transthyretin (TTR) protein in tissues. Mutations in TTR gene destabilize TTR protein to misfold from its native tetramer form to amyloidogenic monomer form. In endemic countries, TTR-FAP presents with length-dependent small fiber neuropathy, however in non-endemic countries clinical features can be highly variable. Genetic testing for TTR gene is mandatory for the diagnosis. Demonstrating amyloid deposits in tissues may be necessary for distinguishing symptomatic patients from asymptomatic carriers. Routine follow-up should include a wide range of tests to demonstrate systemic involvement. In recent years, treatment of TTR-FAP has significantly improved with new therapeutic approaches. TTR stabilizers and TTR-gene silencing drugs prevent the progression of the disease. Monoclonal antibodies that target amyloid deposits are currently under development. Early initiation of the treatment is important for better functional outcome.

The identification of a transthyretin variant p.D38G in a Chinese family with early-onset leptomeningeal amyloidosis

Familial amyloid polyneuropathies (FAPs) are life-threatening, autosomal dominant diseases resulting, in most instances, from transthyretin gene (TTR) variants. A small number of TTR variants lead to leptomeningeal amyloidosis (LA), which is a rare FAP subtype with late-onset central nervous system (CNS) impairment symptoms. Previous studies suggest that LA's CNS selectivity was due to complete endoplasmic reticulum-associated degradation of highly destabilized mutants in peripheral tissues. LA's later age at onset (AAO) was due to lower choroid plexus secretory efficacy. This study reports on a family with LA, including six symptomatic and three presymptomatic members. The LA diagnosis was confirmed by leptomeningeal enhancement on contrast MRI, elevated cerebrospinal fluid protein levels, and positive Congo red staining. The predominant symptoms included headaches, dizziness, vomiting, hallucinations, and cognitive impairments which associated with obstructive hydrocephalus. The TTR p.D38G variant with the lowest secretory efficacy was identified as the genetic cause by whole exome sequencing. The family had a statistically significantly earlier mean AAO of 31.3 ± 7.4 (p = 0.001). These uncommon phenotypes indicate unknown factors influencing the progress of CNS impairment via TTR mutants. Medical imaging examinations suggest the potential early diagnosis value of contrast MRI and the importance of ependyma involvement in LA. LA genetic and clinical data were reviewed and summarized. These findings expand the FAPs' phenotypic spectrum and are valuable in FAP diagnosis, treatment, and further research.

APP Mutations in Cerebral Amyloid Angiopathy with or without Cortical Calcifications: Report of Three Families and a Literature Review

BACKGROUND

Specific APP mutations cause cerebral amyloid angiopathy (CAA) with or without Alzheimer's disease (AD).

OBJECTIVE

We aimed at reporting APP mutations associated with CAA, describe the clinical, cerebrospinal fluid AD biomarkers, and neuroimaging features, and compare them with the data from the literature.

METHODS

We performed a retrospective study in two French genetics laboratories by gathering all clinical and neuroimaging data from patients referred for a genetic diagnosis of CAA with an age of onset before 66 years and fulfilling the other Boston revised criteria. We studied the segregation of mutations in families and performed a comprehensive literature review of all cases reported with the same APP mutation.

RESULTS

We screened APP in 61 unrelated French patients. Three mutations, located in the Aβ coding region, were detected in five patients from three families: p.Ala692Gly (Flemish), p.Glu693Lys (Italian), and p.Asp694Asn (Iowa). Patients exhibited CAA and progressive cognitive impairment associated with cortical calcifications in the Iowa and Italian mutation carriers, but not the patient carrying the Flemish mutation.

CONCLUSIONS

This is the first evidence of cortical calcification in patients with an APP mutation other than the Iowa mutation. We discuss the radiological, cerebrospinal fluid, and clinical phenotype of patients carrying these mutations in the literature.

Ocular Manifestations of Familial Transthyretin Amyloidosis

PURPOSE

Among patients with familial amyloidosis, mutation in the transthyretin (TTR) protein is the most common type. Patients with TTR amyloidosis have been noted to have ocular, especially vitreous, involvement. In this report, an analysis of the types and frequency of ocular manifestations in TTR amyloidosis is presented.

DESIGN

Observational case series.

METHODS

Two hundred and sixty-three patients who presented to Mayo Clinic with TTR amyloidosis between January 1, 1970, and November 1, 2014, consented to be included in the Mayo Clinic amyloidosis database maintained by the Department of Hematology. Fifty-four patients had ocular examinations at a mean of 4.25 ± 3.93 months after systemic symptoms.

RESULTS

Of 108 examined eyes in 54 patients with TTR amyloidosis, there were 26 eyes (24%) in 13 patients with ocular involvement. Patients with ocular involvement were more likely to be women than those without ocular involvement (46% vs 15%, respectively, P = .008) and have significantly worse visual acuity (VA) at presentation (logMAR 0.24 [Snellen equivalent 20/30] vs logMAR 0.00 [Snellen equivalent 20/20], P = .017). The ophthalmic findings included vitreous amyloid (26/26, 100%), neurotrophic keratitis (2/26, 8%), glaucoma (5/26, 19%), and tortuous retinal vessels (4/26, 15%). The glaucoma was classified as open-angle (2/26), exfoliative (2/26), and neovascular following central retinal vein occlusion from amyloidosis (1/26). Ten patients underwent vitrectomy for visually significant vitreous amyloidosis, which significantly improved VA from a baseline of logMAR 0.70 (Snellen equivalent 20/100) to logMAR 0.05 (Snellen equivalent ∼20/20), P = .003. Three TTR mutations, Glu89Lys, Gly47Arg, and homozygous Gly6Ser, not previously described, were associated with vitreous amyloid.

CONCLUSION

In this large cohort of patients with TTR amyloidosis, female sex and decreased VA were associated with ocular amyloid. Three mutations that have not been previously reported to have vitreous involvement were described: Glu89Lys, Gly47Arg, and homozygous Gly6Ser.

Current and future treatment of amyloid diseases

There are more than 30 human proteins whose aggregation appears to cause degenerative maladies referred to as amyloid diseases or amyloidoses. These disorders are named after the characteristic cross-β-sheet amyloid fibrils that accumulate systemically or are localized to specific organs. In most cases, current treatment is limited to symptomatic approaches and thus disease-modifying therapies are needed. Alzheimer's disease is a neurodegenerative disorder with extracellular amyloid β-peptide (Aβ) fibrils and intracellular tau neurofibrillary tangles as pathological hallmarks. Numerous clinical trials have been conducted with passive and active immunotherapy, and small molecules to inhibit Aβ formation and aggregation or to enhance Aβ clearance; so far such clinical trials have been unsuccessful. Novel strategies are therefore required and here we will discuss the possibility of utilizing the chaperone BRICHOS to prevent Aβ aggregation and toxicity. Type 2 diabetes mellitus is symptomatically treated with insulin. However, the underlying pathology is linked to the aggregation and progressive accumulation of islet amyloid polypeptide as fibrils and oligomers, which are cytotoxic. Several compounds have been shown to inhibit islet amyloid aggregation and cytotoxicity in vitro. Future animal studies and clinical trials have to be conducted to determine their efficacy in vivo. The transthyretin (TTR) amyloidoses are a group of systemic degenerative diseases compromising multiple organ systems, caused by TTR aggregation. Liver transplantation decreases the generation of misfolded TTR and improves the quality of life for a subgroup of this patient population. Compounds that stabilize the natively folded, nonamyloidogenic, tetrameric conformation of TTR have been developed and the drug tafamidis is available as a promising treatment.

Cerebral amyloid angiopathy in posttransplant patients with hereditary ATTR amyloidosis

OBJECTIVE

To investigate the prevalence and clinical features of posttransplant CNS symptoms in patients with hereditary ATTR amyloidosis and their Pittsburgh compound B (PiB)-PET imaging correlates.

METHODS

We monitored prevalence and type of CNS symptoms in 53 consecutive posttransplant patients with hereditary ATTR amyloidosis. (11)C-PiB-PET was performed in 15 patients with various disease durations. We also analyzed pathologic and biochemical characteristics of ATTR amyloid deposition in the brain of a posttransplant patient.

RESULTS

Transient focal neurologic episodes (TFNEs) attributed to ATTR-type cerebral amyloid angiopathy (CAA) were found in 11.3% of posttransplant hereditary ATTR amyloidosis patients. TFNE occurred on average 16.8 years after onset of the disease. Patients with longer duration of illness (≥10 years) showed increased (11)C-PiB retention in the brain. The (11)C-PiB accumulation pattern in hereditary ATTR amyloidosis was unique and different from those in Alzheimer disease or Aβ-type CAA. In the autopsy case, ATTR amyloid deposition was mainly localized to leptomeningeal vessels and leptomeninges of the brain. Amyloid fibrils in the brain were almost completely composed of variant transthyretin (TTR).

CONCLUSIONS

TFNE due to ATTR-type CAA occurred frequently in posttransplant patients with long disease durations. (11)C-PiB-PET is a useful diagnostic tool for ATTR-type CAA. ATTR amyloid deposition in the CNS, as measured by PiB-PET, was detected approximately 10 years before onset of TFNE.

Genotypic and phenotypic presentation of transthyretin-related familial amyloid polyneuropathy (TTR-FAP) in Turkey

Transthyretin-related familial amyloid polyneuropathy (TTR-FAP) is an autosomal dominant disorder caused by mutations of the transthyretin (TTR) gene. The mutant amyloidogenic transthyretin protein causes the systemic accumulation of amyloid fibrils that result in organ dysfunction. TTR-associated FAP is a progressive and fatal disease, if left untreated, and should be considered in the differential diagnosis of any person presenting with a progressive polyneuropathy, particularly with accompanying autonomic involvement. The clinical, electrophysiological, histopathological, and genetic characteristics of 17 patients from Turkey (5 female, 13 male) from nine families with polyneuropathy and mutations in TTR were evaluated. Sequence analysis of the TTR gene revealed five mutations (Val30Met, Glu89Gln, Gly53Glu, Glu54Gly and Gly47Glu). Mean age at disease onset was 40.4 ± 13.9 years (range 21-66 years). The most commonly reported initial complaint was paresthesia in the feet (asymmetric in three patients). Three patients (2 male) with the Glu89Gln mutation presented with carpal tunnel syndrome. Two patients with the Gly53Glu mutation showed episodes of dysarthria and hemiparesis, consistent with this genotype. Seven patients died during the period of follow-up as a result of systemic involvement. Our study suggests that a cohort of patients from Turkey with TTR-FAP exhibits clinical and genetic heterogeneity.

CNS involvement in V30M transthyretin amyloidosis: clinical, neuropathological and biochemical findings

OBJECTIVES

Since liver transplant (LT) was introduced to treat patients with familial amyloid polyneuropathy carrying the V30M mutation (ATTR-V30M), ocular and cardiac complications have developed. Long-term central nervous system (CNS) involvement was not investigated. Our goals were to: (1) identify and characterise focal neurological episodes (FNEs) due to CNS dysfunction in ATTR-V30M patients; (2) characterise neuropathological features and temporal profile of CNS transthyretin amyloidosis.

METHODS

We monitored the presence and type of FNEs in 87 consecutive ATTR-V30M and 35 non-ATTR LT patients. FNEs were investigated with CT scan, EEG and extensive neurovascular workup. MRI studies were not performed because all patients had cardiac pacemakers as part of the LT protocol. We characterised transthyretin amyloid deposition in the brains of seven ATTR-V30M patients, dead 3-13 years after polyneuropathy onset.

RESULTS

FNEs occurred in 31% (27/87) of ATTR-V30M and in 5.7% (2/35) of the non-ATTR transplanted patients (OR=7.0, 95% CI 1.5 to 33.5). FNEs occurred on average 14.6 years after disease onset (95% CI 13.3 to 16.0) in ATTR-V30M patients, which is beyond the life expectancy of non-transplanted ATTR-V30M patients (10.9, 95% CI 10.5 to 11.3). ATTR-V30M patients with FNEs had longer disease duration (OR=1.24; 95% CI 1.07 to 1.43), renal dysfunction (OR=4.65; 95% CI 1.20 to 18.05) and were men (OR=3.57; 95% CI 1.02 to 12.30). CNS transthyretin amyloidosis was already present 3 years after polyneuropathy onset and progressed from the meninges and its vessels towards meningocortical vessels and the superficial brain parenchyma, as disease duration increased.

CONCLUSIONS

Our findings indicate that CNS clinical involvement occurs in ATTR-V30M patients regardless of LT. Longer disease duration after LT can provide the necessary time for transthyretin amyloidosis to progress until it becomes clinically relevant. Highly sensitive imaging methods are needed to identify and monitor brain ATTR. Disease modifying therapies should consider brain TTR as a target.

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.

Molecular tweezers targeting transthyretin amyloidosis

Transthyretin (TTR) amyloidoses comprise a wide spectrum of acquired and hereditary diseases triggered by extracellular deposition of toxic TTR aggregates in various organs. Despite recent advances regarding the elucidation of the molecular mechanisms underlying TTR misfolding and pathogenic self-assembly, there is still no effective therapy for treatment of these fatal disorders. Recently, the "molecular tweezers", CLR01, has been reported to inhibit self-assembly and toxicity of different amyloidogenic proteins in vitro, including TTR, by interfering with hydrophobic and electrostatic interactions known to play an important role in the aggregation process. In addition, CLR01 showed therapeutic effects in animal models of Alzheimer's disease and Parkinson's disease. Here, we assessed the ability of CLR01 to modulate TTR misfolding and aggregation in cell culture and in an animal model. In cell culture assays we found that CLR01 inhibited TTR oligomerization in the conditioned medium and alleviated TTR-induced neurotoxicity by redirecting TTR aggregation into the formation of innocuous assemblies. To determine whether CLR01 was effective in vivo, we tested the compound in mice expressing TTR V30M, a model of familial amyloidotic polyneuropathy, which recapitulates the main pathological features of the human disease. Immunohistochemical and Western blot analyses showed a significant decrease in TTR burden in the gastrointestinal tract and the peripheral nervous system in mice treated with CLR01, with a concomitant reduction in aggregate-induced endoplasmic reticulum stress response, protein oxidation, and apoptosis. Taken together, our preclinical data suggest that CLR01 is a promising lead compound for development of innovative, disease-modifying therapy for TTR amyloidosis.

Amyloid neuropathies

Peripheral neuropathy is a common complication of many of the systemic amyloidoses. Although the cause of neuropathy is not entirely clear, it is likely related to amyloid deposition within the nerve. This may lead to focal, multifocal, or diffuse neuropathies involving sensory, motor and/or autonomic fibers. The presenting symptoms depend on the distribution of nerves affected. One of the most common phenotypes is sensorimotor polyneuropathy, which is characterized by symptoms of neuropathic pain, numbness, and in advanced cases weakness. Symptoms begin in the feet and ultimately progress to the proximal legs and hands. The most common focal neuropathy is a median neuropathy at the wrist, clinically known as carpal tunnel syndrome. Carpal tunnel symptoms may include pain and sensory disturbances in the lateral palm and fingers; hand weakness may ensue if the focal neuropathy is severe. Autonomic neuropathy may affect a variety of organ systems such as the cardiovascular, gastrointestinal, and genitourinary systems. Symptoms may be non-specific making the diagnosis of autonomic neuropathy more difficult to identify. However, it is important to recognize and distinguish autonomic neuropathy from diseases of the end-organs themselves. This article reviews the inherited and acquired amyloidoses that affect the peripheral nervous system including familial amyloid polyneuropathy, and primary, secondary and senile amyloidosis. We emphasize the clinical presentation of the neurologic aspects of these diseases, physical examination findings, appropriate diagnostic evaluation, treatment and prognosis.

Detection of metals and metalloproteins in the plasma of stroke patients by mass spectrometry methods

Stroke is the leading cause of adult disability, worldwide. Metalloproteins and metals play key roles in epigenetic events in living organisms, including hypertension, the most important modifiable risk factor for stroke. Thus, metalloproteins may be important target biomarkers for disease diagnosis. The primary goal of this study was to assess metal containing proteins in blood plasma, detected by ICP-MS, followed by ESIMS for peptide/protein identification. We then compared the relative concentration differences between samples from patients with ischemic stroke, hemorrhagic stroke and stroke mimics. In 29 plasma samples (10 stroke mimics, 10 ischemic stroke and 9 hemorrhagic stroke patients) previously collected from patients who presented to the University of Cincinnati Emergency Department within 12 hours of symptom onset for a plasma banking project. For the metal associated protein study, Mg, Mn, Cu, Se concentrations were statistically different when compared between stroke mimics vs. ischemic stroke patients and ischemic stroke patients vs. hemorrhagic stroke patients. Pb concentrations were statistically different when compared between stroke mimics vs. ischemic stroke patients and Mo levels were statistically the same among the three groups. In addition, we also report concentration levels and preliminary correlation studies for total elemental analysis among the three sets of patients. This pilot study demonstrates that mass spectrometry methods may be highly valuable in detecting novel stroke biomarkers in blood plasma. Expanded studies are warranted to confirm these findings.

The hemorrhage caused by sporadic-type cerebral amyloid angiopathy occurs primarily in the cerebral sulci

We examined a solitary hematoma in a patient with sporadic cerebral amyloid angiopathy (CAA). The hematoma affected the middle frontal sulcus, cerebral cortex (CC) and subcortical frontal white matter (sfWM). We embedded the hematoma in four paraffin blocks, each of which was cut serially into 6-µm-thick sections. The first section and every 18th section from each block were subjected to Elastica-Goldner (E-G) staining, and the distribution and diameter of the ruptured blood vessels (rBVs) were examined. The rBVs were then marked on diagrams representing each E-G-stained section. The present study yielded the following important findings: (i), early- and recently ruptured Aβ-positive arteries were present mainly in the intrasulcal hematoma (ISH), rather than in the CC; (ii) many early-ruptured arteries in the ISH were larger in diameter than those in the CC; and (iii) ruptures of the cortical arteries, even near the cortical surface, did not occur so frequently and the ruptured vessels were small in size. We concluded that in patients with subcortical hematoma caused by sporadic-type CAA, successive rupturse of the meningeal vessels, mainly arteries, occur in the cerebral sulcus initially, followed by formation of an ISH and development of a fresh hemorrhagic or anemic infarct in the CC surrounding the ISH, the latter in most cases then extending into the brain parenchyma through the necrotic CC at the depth of the sulcus, finally creating a secondary hematoma in the subcortical white matter.

The neuromuscular manifestations of amyloidosis

Amyloidosis is a systemic disease that may be acquired or hereditary and which results in the deposition of amyloid fibrils in a variety of tissues causing their progressive dysfunction. Although the clinical presentation often is dominated by cardiac or renal failure, peripheral neuropathy may be a significant or the initial manifestation, resulting in presentation to the neurologist. Diagnosis often is challenging and may require multiple diagnostic procedures, including more than one biopsy. Acquired and hereditary amyloidosis can be definitively distinguished from one another only by immunohistochemical staining or molecular genetic testing. Treatment remains a challenge, although chemotherapy and autologous stem cell transplantation offer hope for those with primary systemic amyloidosis, whereas liver transplantation is effective for some forms of hereditary amyloid neuropathy. Much less commonly, myopathy may be a clinically significant manifestation of amyloidosis.

Suppression of choroid plexus transthyretin levels by antisense oligonucleotide treatment

Leptomeningeal amyloidosis associated with mutations in transthyretin (TTR) is a rare but fatal form of amyloidosis. Dementia and intracerebral haemorrhage are prominent features of this disease for which no specific therapy is known. In previous studies, we have shown that antisense oligonucleotides (ASOs) specific for human TTR could inhibit hepatic synthesis of TTR in mice transgenic for a human amyloid-associated TTR and may offer a medical means of treating systemic TTR amyloidosis. Parenteral administration of TTR-specific ASO, however, had no effect on the expression of TTR by the choroid plexus, which is believed to be the source of the amyloid protein in patients who have leptomeningeal amyloidosis. In the present study, mice transgenic for the human TTR amyloid-associated mutation Ile84Ser were treated by administration of TTR-specific ASO (50 microg or 75 microg per day) via an osmotic pump into the cerebral ventricular system over a 4-week period. Intraventricular administration of TTR-specific ASO significantly reduced choroid human TTR mRNA levels, and these findings correlated with decreased TTR in choroid plexus epithelial cells as demonstrated by immunohistochemistry. Suppression of choroid TTR expression by intraventricular administered ASO may offer a medical means of treating leptomeningeal amyloidosis.

[Focal subarachnoid hemorrhage and cerebral amyloid angiopathy: a non-fortuitous association]

INTRODUCTION

Cerebral amyloid angiopathy is a degenerative angiopathy due to amyloid deposits in the walls of the meningeal and cortical vessels. It is considered as a major cause of cerebral hemorrhage to the elderly. It was recently demonstrated that the association of focal meningeal bleedings and cerebral hemorrhage is very suggestive of cerebral amyloid angiopathy. In contrast, the links between subarachnoid hemorrhage and amyloid angiopathy are less well-known.

CASES REPORTS

We report nine cases of cerebral amyloid angiopathy. The clinical presentation was variable, but all had at least one inaugural meningeal bleeding. As cortico-meningeal biopsies were not performed the Boston criteria were used to establish the diagnosis.

CONCLUSION

Cerebral amyloid angiopathy is an underestimated cause of subarachnoid hemorrhage. Our observations show that this diagnosis should be evoked when focal meningeal bleeding occurs without head trauma or when focal subarachnoid hemorrhage is followed by a subcortical hematoma in an elderly subject.

Benefits of magnetic resonance image scanning in progressive, bilateral, sensorineural hearing loss: a case of leptomeningeal haemosiderosis

OBJECTIVE

Magnetic resonance imaging is a routine investigation in cases of asymmetric sensorineural hearing loss, but it is not routinely used to investigate bilateral sensorineural hearing loss.

METHOD

This case report illustrates the benefits of magnetic resonance image scanning in the latter patient group.

RESULTS

A 53-year-old man with rapidly progressive, symmetrical, bilateral, sensorineural hearing loss was found also to have anosmia, imbalance and incoordination. Magnetic resonance image scanning demonstrated leptomeningeal haemosiderosis. Progressive, bilateral, sensorineural hearing loss is the most common presentation of this condition and magnetic resonance imaging is the diagnostic investigation of choice.

CONCLUSION

There are potential treatments for leptomeningeal haemosiderosis which prevent further irreversible damage, if a bleeding source can be found. Hearing loss may be due to cochlear or retrocochlear pathology. Cochlear implantation may be indicated.

Superficial siderosis: a potential diagnostic marker of cerebral amyloid angiopathy in Alzheimer disease

BACKGROUND AND PURPOSE

Superficial siderosis of the central nervous system results from chronic bleeding in the superficial layers of the cortex and spinal cord. In cerebral amyloid angiopathy (CAA), there is amyloid deposition in meningeal and meningo-cortical arteries and capillaries, predisposing them to rupture. CAA is frequently associated with Alzheimer disease (AD).

METHODS

We report a series of 3 AD patients with MRI evidence of superficial siderosis. Two had neuropathological examination confirming superficial siderosis, AD, and CAA.

CONCLUSIONS

Superficial siderosis should be recognized within the spectrum of AD with CAA and considered as a possible antemortem diagnostic feature.

Oculoleptomeningeal amyloidosis in a patient with a TTR Val30Gly mutation in the transthyretin gene

OBJECTIVE

To describe a patient with oculoleptomeningeal amyloidosis associated with infiltration of the vitreous, elevated intraocular pressures (IOPs), and seizures caused by a TTR Val30Gly mutation in the transthyretin gene.

DESIGN

Interventional clinicopathologic report.

PARTICIPANT

A 44-year-old man with refractory bilateral intermediate uveitis, elevated IOPs, and seizures.

INTERVENTION

The patient underwent diagnostic pars plana vitrectomy in both eyes. Intraocular and intracerebral pressures were controlled by trabeculectomy and cerebroventricular shunt placement, respectively.

MAIN OUTCOME MEASURES

Visual acuity, histopathologic analysis of vitreous and leptomeningeal tissue, genetic testing, and magnetic resonance imaging of the brain.

RESULTS

After failure of the patient to respond to topical and periocular corticosteroid therapy, a pars plana vitrectomy was performed and revealed amorphous material that showed green birefringence and dichroism on Congo red staining, establishing the diagnosis of vitreous amyloidosis. A full medical workup, including genetic testing, revealed a TTR Val30Gly mutation in the transthyretin gene. The patient subsequently developed elevated IOPs requiring bilateral trabeculectomy surgery and episodic seizures associated with leptomeningeal enhancement on magnetic resonance imaging. Histopathological analysis of a leptomeningeal biopsy taken at the time of surgery revealed amyloid infiltration, confirming the diagnosis of oculoleptomeningeal involvement by his amyloidosis. A ventriculoperitoneal shunt was placed.

CONCLUSION

Amyloidosis should be considered in patients who present with vitritis that is unresponsive to corticosteroid therapy. Vitreous biopsy with histopathological analysis is recommended in these cases. Additionally, sequencing of the transthyretin gene should be considered in patients with vitreous amyloidosis to help establish known genetic syndromes and predict both ocular and systemic comorbidities. Although not described previously, elevated IOP may develop in patients with vitreous amyloidosis due to a TTR Val30Gly mutation in the transthyretin gene.

Clinical phenotypes of Cerebral Amyloid Angiopathy

The term Cerebral Amyloid Angiopathy (CAA) is used to describe the pathological changes occurring in cerebral blood vessels, both leptomeningeal and cortical that result from the deposition of amyloid proteins. This CNS vasculopathy is associated with a spectrum of clinical phenotypes that include both ischemic and hemorrhagic presentations. Dementia, cognitive impairment and transient neurological symptoms or signs are also being increasingly recognized as part of the CAA clinical spectrum. This review covers the clinical, pathological and neuroimaging aspects of CAA.

A novel amyloidogenic transthyretin variant, Gly53Ala, associated with intermittent headaches and ataxia

We report a novel transthyretin variant, Gly53Ala, in a 44-year-old British woman who presented with severe episodic headaches, often with focal neurological deficit, before developing progressive ataxia, depression, dementia and eventually peripheral neuropathy. Transthyretin amyloidosis was confirmed on biopsy of the heart muscle. Serum amyloid P component scintigraphy did not show visceral amyloid in extra-cardiac sites, but magnetic resonance imaging indicated diffuse leptomeningeal amyloidosis.

Angiopathie amyloïde cérébrale sporadique

INTRODUCTION

Sporadic cerebral amyloid angiopathy (CAA) is a microangiopathy identified by neuropathological examination in more than 30 percent of patients over 85 years of age.

STATE OF ART

Boston criteria for diagnosis of CAA--related hemorrhage are as follows: "definite CAA", "Probable CAA with supporting pathology", "Probable CAA" and "Possible CAA". Clinical manifestations of CAA are either lobar, cortical, corticosubcortical or cerebellar hemorrhages associated with progressive dementia. Dementia, corresponding either to Alzheimer disease, vascular or mixed dementia, precedes hemorrhages in 25 to 40 percent of cases. Brain MRI can demonstrate microbleeding.

PERSPECTIVES

This review compares data regarding CAA prevalence, intracranial hemorrhages, and their risk factors in old patients. Diagnosis and preventive strategies are discussed. It would be useful to identify those affected by CAA among elderly demented patients with atrial fibrillation requiring anticoagulation therapy.

CONCLUSIONS

CAA is suspected in the presence of recurrent lobar or cerebellar hemorrhages, and moreover if associated with pre-existing dementia. In elderly demented patients, MRI criteria to detect CAA should be considered in order to prevent hemorrhage risk, particularly after anticoagulation therapy.

Biochemical characteristics of variant transthyretins causing hereditary leptomeningeal amyloidosis

Transthyretin (TTR) is a tetrameric protein that can dissociate into amyloidogenic monomers and cause TTR-related amyloidosis. A rare phenotype, called hereditary leptomeningeal TTR amyloidosis, in which TTR amyloid deposition occurs mainly in leptomeninges and subarachnoid vessels, has been reported in patients with several different TTR variants. In the present study, we examined TTR variants immunoprecipitated from the serum and cerebrospinal fluid (CSF) of patients with hereditary leptomeningeal TTR amyloidosis using matrix-assisted laser desorption ionization/time-of-flight mass spectrometry (IP-Mass method). The leptomeningeal-type TTR variants were not detected in the serum but were found at low levels in the CSF. The undetectable levels of the leptomeningeal-type TTR variants in serum could explain the minute amounts of systemic deposition of these variants. The relatively high level of unstable TTR variants in CSF, probably due to increased secretion from the choroid plexus, is considered to be the pathogenesis of the leptomeningeal-type of TTR amyloidosis.

Cardiomyopathy in Swedish patients with the Gly53Glu and His88Arg transthyretin variants

We report two new amyloidogenic transthyretin (TTR) variants detected in the Swedish population. One variant was previously unknown, while the other has been described in a French family. In Swedish patients, both variants have caused late-onset cardiac amyloidosis characterised by heart failure. In both cases, the diagnosis was determined by the detection of amyloid deposits in skin and/or rectal biopsies and identification of TTR mutations by genetic analysis. The index case of the previously unknown mutation (ATTR His88Arg) was a 66-year-old Swedish man, who sought medical attention for increasing dyspnea. Echocardiographic examination disclosed a restrictive cardiomyopathy, and subsequent examinations disclosed TTR amyloidosis. The patient is alive with moderate symptoms one year after the onset of disease. The index case for the new Swedish mutation (ATTR Gly53Glu) is a woman who sought medical attention at the age of 57 because of increasing dyspnea. Echocardiographic examination disclosed a hypertrophic cardiomyopathy with diastolic impairment. The diagnosis of systemic amyloidosis was made by fat aspiration biopsy and histopathology. The patient developed severe intractable heart failure, with pulmonary effusion and ascites. She died four years after the onset of her disease of intractable heart and kidney failure. Post mortem examination of biopsy specimens and blood revealed TTR amyloid deposits and the ATTR Gly53Glu mutation was detected.

Genetics of cerebrovascular disorders

Physicians must be able to recognize stroke caused by a mendelian or mitochondrial disorder. Some genetic disorders such as sickle cell anemia and Fabry disease have proven disease-specific treatments, whereas others have no effective treatment, including cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) and mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS). Proper diagnosis of a genetic disorder has prognostic value and prevents patient exposure to unnecessary and potentially harmful therapeutic agents and diagnostic tests. This article reviews the clinical and genetic features of some mendellan and mitochondrial disorders associated with ischemic stroke, hemorrhagic stroke, and cerebrovascular malformations.

Longitudinal Analysis of Hearing Loss in a Case of Hemosiderosis of the Central Nervous System

OBJECTIVE

To describe cochleovestibular aspects of superficial hemosiderosis of the central nervous system.

BACKGROUND

Superficial hemosiderosis of the central nervous system is a rare disease in which cochleovestibular impairment, cerebellar ataxia, and myelopathy are the most frequent signs. Chronic recurrent subarachnoidal hemorrhage with bleeding into the cerebrospinal fluid is the cause of deposition of hemosiderin in leptomeningeal and subpial tissue, cranial nerves, and spinal cord. Removing the cause of bleeding can prevent irreversible damage to these structures. Because this is the only effective treatment, an early diagnosis is crucial.

STUDY DESIGN

Retrospective case review.

SETTING

Tertiary referral center.

PATIENT

A 72-year-old woman with superficial hemosiderosis of the central nervous system that developed when she was age 39.

METHODS

Neurologic and imaging diagnostic examinations and longitudinal evaluation of cochleovestibular features were performed. Neurosurgery was not performed.

RESULTS

Progressive bilateral sensorineural hearing loss and severe vestibular hyporeflexia developed within 15 years, which can be attributed to lesions in the cochleovestibular system. Additional pathology of the central nervous system developed later.

CONCLUSION

The patient demonstrated cochlear and vestibular findings that are typical of this pathologic condition. It is the first documented case with extensive serial audiometry used to precisely outline the degree of hearing deterioration during the course of the disease.

Energetic characteristics of the new transthyretin variant A25T may explain its atypical central nervous system pathology

Transthyretin (TTR) is a tetrameric protein that must misfold to form amyloid fibrils. Misfolding includes rate-limiting tetramer dissociation, followed by fast tertiary structural changes that enable aggregation. Amyloidogenesis of wild-type (WT) TTR causes a late-onset cardiac disease called senile systemic amyloidosis. The aggregation of one of > 80 TTR variants leads to familial amyloidosis encompassing a collection of disorders characterized by peripheral neuropathy and/or cardiomyopathy. Prominent central nervous system (CNS) impairment is rare in TTR amyloidosis. Herein, we identify a new A25T TTR variant in a Japanese patient who presented with CNS amyloidosis at age 42 and peripheral neuropathy at age 44. The A25T variant is the most destabilized and fastest dissociating TTR tetramer published to date, yet, surprising, disease onset is in the fifth decade. Quantification of A25T TTR in the serum of this heterozygote reveals low levels relative to WT, suggesting that protein concentration influences disease phenotype. Another recently characterized TTR CNS variant (D18G TTR) exhibits strictly analogous characteristics, suggesting that instability coupled with low serum concentrations is the signature of CNS pathology and protects against early-onset systemic amyloidosis. The low A25T serum concentration may be explained either by impaired secretion from the liver or by increased clearance, both scenarios consistent with A25T's low kinetic and thermodynamic stability. Liver transplantation is the only known treatment for familial amyloid polyneuropathy. This is a form of gene therapy that removes the variant protein from serum preventing systemic amyloidosis. Unfortunately, the choroid plexus would have to be resected to remove A25T from the CSF-the source of the CNS TTR amyloid. Herein we demonstrate that small-molecule tetramer stabilizers represent an attractive therapeutic strategy to inhibit A25T misfolding and CNS amyloidosis. Specifically, 2-[(3,5-dichlorophenyl)amino]benzoic acid is an excellent inhibitor of A25T TTR amyloidosis in vitro.