Familial amyloid polyneuropathy Adams, David; Cauquil, Cécile; Labeyrie, Céline
Current opinion in neurology,
10/2017, Letnik:
30, Številka:
5
Journal Article
Recenzirano
Transthyretin familial amyloid polyneuropathy is the most disabling hereditary polyneuropathy of adult onset because of a point mutation of transthyretin gene. This review updates our knowledge about ...natural history of the disease, phenotypes, diagnosis tools for small and large fibers involvement, expert's consensus for both symptomatic and asymptomatic follow-up, and treatment's research.
Access to TTR gene sequencing permit diagnosis and first reports of the disease in nonendemic countries (EU countries, United States, China, India). Most studies showed a more severe natural history of the neuropathy in nonendemic countries. First European consensus for management has been established. New long-term results allow selection of best candidates for liver transplantation based on phenotype and cardiac involvement. Multimodal evaluation of small fiber neuropathy and resonance magnetic neurography are under development. New results are available for long-term effect of tafamidis in late-onset patients. TTR gene silencing drugs are subject to phase 3 clinical trials.
New methods for the evaluation of the disease are being developed. The TTR gene silencing strategy will be available by the end of 2017.
Transthyretin Familial Amyloid Polyneuropathy (TTR-FAP) is a rare disease with autosomal dominant transmission due to a point mutation of the TTR gene. By removing the main source of systemic mutant ...TTR, liver transplantation (LT) has become the reference therapy of this severe and fatal polyneuropathy of adult-onset, stopping disease progression in subgroup of patients. Recently, new therapeutic strategies have emerged, which intend to stabilize TTR or to silence the TTR gene. Amongst them, the TTR kinetic stabilizer tafamidis is the first drug approved in the EU.
We shall review the natural history of TTR-FAP and the best indications for LT. Data on the efficacy, safety and tolerability of the TTR kinetic stabilizers, tafamidis and diflunisal, have been reviewed, from the pivotal Phase III clinical trials published in PubMed medical journals or presented at international meetings. We will review the ongoing phase III clinical trials of TTR gene silencing with RNAi therapeutics and ASO published in clinicaltrialgov.
Due to the data on efficacy, tolerability, safety, tafamidis and diflunisal became the first line anti-amyloid treatment in stage 1 TTR-FAP. Both drugs slow progression of the disease. Only tafamidis got marketing authorization. We are waiting for results of the 2 phase III clinical trials of TTR gene silencing in varied stages of the disease.
Introduction
IgG4 antibodies against neurofascin (Nfasc155 and Nfasc140/186), contactin (CNTN1) and contactin-associated protein (Caspr1) are described in specific subtypes of chronic inflammatory ...demyelinating polyradiculoneuropathy (CIDP). Our objective was to assess, in a real-life practice, the incidence, the clinical features and the response to treatment of these forms of CIDP.
Methods
1500 sera of patients suspected of having CIDP from France, Belgium and Switzerland were prospectively tested using a flow cytometry technique. The characteristics of patients with antibodies against the node of Ranvier were compared to 100 seronegative CIDP from our department.
Results
IgG4 antibodies against Nfasc155, CNTN1, and Caspr1 were, respectively, detected in 15 (prevalence 1%), 10 (0.7%) and 2 (0.2%) sera. Antibodies specific of the Nfasc140/186 were not detected.
All subjects with antibodies against the node of Ranvier fulfilled diagnostic criteria for CIDP.
CIDP with anti-Nfasc155 were younger, had more sensory ataxia and postural tremor than seronegative CIDP. CIDP with anti-CNTN1 had more frequent subacute onset and facial paralysis, commoner renal involvement with membranous glomerulonephritis and greater disability, than seronegative CIDP. CIDP with anti-Caspr1 had more frequent respiratory failure and cranial nerve involvement but not more neuropathic pain than seronegative CIDP. Intravenous immunoglobulins were ineffective in most seropositive patients. Rituximab produced dramatic improvement in disability and decreased antibodies titres in 13 seropositive patients (8 with anti-Nfasc155 and 5 with anti-CNTN1 antibodies).
Conclusions
Although rare, anti-paranodal antibodies are clinically valuable, because they are associated with specific phenotypes and therapeutic response.
Introduction Progressive Multifocal Leukoencephalopathy (PML) is a rare and deadly demyelinating disease caused by JC virus (JCV) replication in the central nervous system. PML occurs exclusively in ...patients with severe underlying immune deficiencies, including AIDS and hematological malignancies. PML has also emerged as a significant threat to patients on potent new immunosuppressive biologics, including natalizumab in multiple sclerosis. Methods Here, we developed an IFN-γ release assay (IGRA) that mainly detects JCV-specific effector memory T cells and effectors T cells in the blood. Results This assay was frequently positive in patients with active PML (with a positive JCV PCR in CSF) of various underlying immunosuppression causes (84% sensitivity). Only 3% of healthy donors had a positive response (97% specificity). The frequency of positivity also increased in multiple sclerosis patients according to the time on natalizumab (up to 36% in patients treated for more than 48 months, who are considered at a higher risk of PML). Discussion The results show this assay’s frequent or increased positivity in patients with PML or an increased risk of PML, respectively. The assay may help to stratify the risk of PML.
Background and purpose
This study was undertaken to assess skin biopsy as a marker of disease onset and severity in hereditary transthyretin amyloidosis with polyneuropathy (ATTRv‐PN), a treatable ...disease.
Methods
In this single center retrospective study, skin Congo red staining and intraepidermal nerve fiber density (IENFD) were evaluated in symptomatic ATTRv‐PN patients and asymptomatic TTR gene mutation carriers between 2012 and 2019. Non‐ATTRv subjects with suspected small fiber neuropathy who underwent skin biopsy during the same timespan were used as controls.
Results
One hundred eighty‐three symptomatic ATTRv‐PN patients, 36 asymptomatic carriers, and 537 non‐ATTRv patients were included. Skin biopsy demonstrated amyloid depositions in 80% of the 183 symptomatic cases. Skin amyloid deposits were found in 75% of early stage ATTRv‐PN patients, and in 14% of asymptomatic carriers. All 183 symptomatic and 34 of 36 asymptomatic patients displayed decreased ankle IENFD with a proximal–distal gradient distribution, and reduced IEFND correlated with disease severity and duration.
Conclusions
Our study demonstrates skin amyloid deposits are a marker of ATTRv‐PN disease onset, and decreased IENFD a marker of disease progression. These results are of major importance for the early identification of ATTRv‐PN patients in need of disease‐modifying treatments.
Skin biopsy provides useful information in hereditary transthyretin amyloidosis with polyneuropathy. Amyloid deposition in skin is a biomarker of disease onset in paucisymptomatic subjects, especially in early onset Val30Met. Small nerve fiber reduction, which often precedes disease onset, correlates with disease severity.
To investigate the relationship between the ophthalmic and systemic phenotypes in patients with hereditary transthyretin amyloidosis with the S77Y mutation (ATTRS77Y).
In this cross-sectional study, ...patients with genetically confirmed ATTRS77Y amyloidosis were enrolled. All patients underwent complete neurological examination, including staging with the Neuropathy Impairment Score (NIS), Polyneuropathy Disability (PND) score; complete cardiological evaluation, including echocardiography, cardiac MRI and/or cardiac scintigraphy and complete ophthalmic evaluation, including slit lamp examination and fundus examination. Ocular ancillary tests (fluorescein and indocyanine green angiography, and anterior segment optical coherence tomography) were performed in cases with abnormal findings. The Kruskal-Wallis test was used for quantitative outcomes and Fisher's exact test for qualitative outcomes. Statistical significance was indicated by p<0.05 (two tailed).
The study sample was composed of 24 ATTRS77Y patients. The mean patient age was 58.4±12.4 years. None of the patients presented with amyloid deposits in the anterior chamber, secondary glaucoma or vitreous amyloidosis. Retinal angiopathy was observed in four patients, complicated with retinal ischaemia in one patient. Conjunctival lymphangiectasia (CL) was detected in 13 patients (54%), associated with perilymphatic amyloid deposits. The presence of CL was statistically associated with more severe neurological disease (NIS=43.3±31.9 vs 18.9±20.4; PND=2.6±1.0 vs 1.4±0.7 in patients with and without CL, respectively; both p<0.05) and amyloid cardiomyopathy (p=0.002).
In ATTRS77Y patients, CL is common and could serve as a potential biomarker for severe systemic disease. There were neither anterior chamber deposits, secondary glaucoma nor vitreous deposits in ATTRS77Y patients.
Hereditary transthyretin amyloidosis is a life-threatening autosomal dominant systemic disease due to pathogenic
variants (ATTRv), mostly affecting the peripheral nerves and heart. The disease is ...characterised by a combination of symptoms, organ involvement and histological amyloid deposition. The available disease-modifying ATTRv treatments (DMTs) are more effective if initiated early. Pathological nerve conduction studies (NCS) results are the cornerstone of large-fibre polyneuropathy diagnosis, but this anomaly occurs late in the disease. We investigated the utility of a multimodal neurological and cardiac evaluation for detecting early disease onset in ATTRv carriers.
We retrospectively analysed a cohort of ATTRv carriers with normal NCS results regardless of symptoms. Multimodal denervation and infiltration evaluations included a clinical questionnaire (Lauria and New York Heart Association (NYHA)) and examination, intra-epidermal nerve fibre density assessment, autonomic assessment based on heart rate variability, Sudoscan, meta-iodo-benzyl-guanidine scintigraphy, cardiac biomarkers, echocardiography, MRI and searches for amyloidosis on skin biopsy and bone scintigraphy.
We included 130 ATTRv carriers (40.8% men, age: 43.6±13.5 years), with 18 amyloidogenic
gene mutations, the majority of which was the late-onset Val30Met variant (42.3%). Amyloidosis was detected in 16.9% of mutation carriers, including 9 (6.9%) with overt disease (Lauria>2 or NYHA>1) and 13 asymptomatic carriers (10%) with organ involvement (small-fibre neuropathy or cardiomyopathy). Most of these patients received DMT. Abnormal test results of unknown significance were obtained for 105 carriers (80.8%). Investigations were normal in only three carriers (2.3%).
Multimodal neurological and cardiac investigation of TTRv carriers is crucial for the early detection of ATTRv amyloidosis and initiation of DMT.
•Patients with antibodies against the node of Ranvier fulfil electrodiagnostic criteria for definite CIDP.•Patients with anti-CNTN1 and anti-NfascC155 antibodies have similar electrophysiological ...patterns.•Electrophysiological abnormalities are more marked in patients with antibodies.
Chronic inflammatory demyelinating polyradiculoneuropathies (CIDP) with antibodies against neurofascin 155 (Nfasc155) or contactin-1 (CNTN1) have distinctive clinical features. Knowledge on their electrophysiological characteristics is still scarce. In this study, we are investigating whether these patients have specific electrophysiological characteristics.
The electrophysiological data from 13 patients with anti-Nfasc155 IgG4 antibodies, 9 with anti-CNTN1 IgG4 antibodies were compared with those of 40 consecutive CIDP patients without antibodies.
All the patients with antibodies against Nfasc155 or CNTN1 fulfilled the EFNS/PNS electrodiagnostic criteria for definite CIDP. There was no electrophysiological difference between patients with anti-CNTN1 and anti-Nfasc155 antibodies. Nerve conduction abnormalities were heterogeneously distributed along nerves trunks and roots. They were more pronounced than in CIDP without antibodies. Motor conduction velocity on median nerve <24 m/s or motor velocity on ulnar nerve <26 m/s or motor distal latency on ulnar nerve >7.4 ms were predictive of positive antibodies against the node of Ranvier with a sensitivity of 59% and a specificity of 93%.
Marked conduction abnormalities may suggest the presence of positive antibodies against the node of Ranvier.
Anti-Nfasc155 and anti-CNTN1 antibodies target the the paranodal axo-glial domain but are associated with nerve conduction abnormalities mimicking a “demyelinating” neuropathy.
Amyloidosis is a complex group of rare conditions. For patients, amyloidosis is severely debilitating: physically and psychologically. Currently, data are lacking to evaluate the medical, economic, ...and social burden of systemic amyloidosis.
To analyse the patient burden according to the main types of systemic amyloidosis.
The French Daily Impact of Amyloidosis study was an observational, cross-sectional and non-interventional study. Adults diagnosed with light chain (AL), transthyretin (ATTR), amyloid A (AA) and other rare forms of amyloidosis were eligible. Data regarding amyloidosis prevalence, diagnosis, management, and impact on everyday life were collected using a study-specific survey built by the Association Française Contre l'Amylose (AFCA) and the four French National Referral Centres for Amyloidosis.
A total of 603 patients, predominantly male (65%) with an average age of 66.8 years, including 170 AL, 224 ATTRv, 109 ATTRwt and 25 AA amyloidosis patients, completed the study-specific survey. The median delay from presentation to confirmed diagnosis was 27.4 months but varied according to amyloidosis type. Patients before diagnosis had breathlessness (49%), tingling sensation (33%), pain (28%), difficulty in walking (28%) and weight loss (22%). Amyloidosis was most frequently suspected (49%) and confirmed (57%) in local hospitals but managed in French amyloidosis referral centres (58%). Patients often reported problems with mobility, usual activities, pain/discomfort and anxiety/depression, but not with self-care.
Systemic amyloidosis severely impacts daily life. The delay to confirmed amyloidosis diagnosis needs to be reduced. Early, effective treatment is required to optimise patient benefits.
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