Avaliação Cintilográfica e Ecocardiográfica em Portadores de Variantes Patogênicas ou Provavelmente Patogênicas do Gene TTR sem Envolvimento Cardíaco Manifesto / Scintigraphic and Echocardiographic Study of Patients with Pathogenic or Probably Pathogenic Variants of the TTR Gene without Overt Cardiac Involvement

Resumo Fundamento: A amiloidose por transtirretina (ATTR) é uma doença infiltrativa causada pela deposição anormal de proteína principalmente no coração e no sistema nervoso periférico. Quando acomete o coração, a doença manifesta-se como uma cardiomiopatia restritiva e, quando afeta o sistema nervoso periférico e autônomo, apresenta-se como uma polineuropatia, podendo ser chamada de Polineuropatia Amiloidótica Familiar (PAF). Existem dois subtipos de ATTR, a ATTR selvagem, em que não há variantes genéticas, e a ATTR hereditária, caracterizada por uma variante no gene que codifica a proteína transtirretina (T/TR). Em ambos os subtipos, o envolvimento cardíaco é o principal marcador prognóstico. Objetivos: Avaliar a prevalência do envolvimento cardíaco subclínico em uma amostra de pacientes com variantes genéticas no gene TTR usando a cintilografia com pirofosfato e o ecocardiograma com strain; comparar os achados cintilográficos e as medidas de strain; avaliar a associação entre PAF e o envolvimento subclínico; e analisar se existe uma associação entre uma variante genética específica e o envolvimento cardíaco. Métodos: Estudo transversal com carreadores de variantes no gene TTR sem sintomas cardiovasculares e sem alterações nos parâmetros da eletrocardiografia ou do ecocardiograma convencional. Todos os pacientes foram submetidos à cintilografia com pirofosfato e à ecocardiografia com análise de strain. O envolvimento cardíaco subclínico, definido como um escore de Perugini ≥ 2, razão Coração (C)/ Hemitórax Contralateral (CL) ≥ 1,5 em uma hora, C/CL ≥ 1,3 na terceira hora, ou um strain longitudinal global (SGL) ≤ −17%. Realizadas análises descritiva e analítica, e aplicados o teste exato de Fisher e o teste de Mann-Whitney. Um valor de p<0,05 foi considerado significativo. Resultados: Os 23 pacientes avaliados apresentavam uma idade mediana de 51 (37-57) anos, 15 (65,2%) eram do sexo feminino, 12 (52,2%) eram pardos, nove (39,1%) apresentavam hipertensão arterial sistêmica, e nove (39,1%) tinham um diagnóstico prévio de PAF. Dos nove pacientes com PAF, oito (34,8%) usavam tafamidis. As variantes genéticas identificadas foram Val142IIe, Val50Met e IIe127Val. O valor mediano do SGL foi −19% (-16% - −20%). Dos 23 pacientes, nove (39,1%; 95% CI = 29-49%) preencheram os critérios de envolvimento cardíaco, seis (26%) somente pelo critério do SGL. Não houve associação entre PAF e um carreador assintomático avaliado por ecocardiograma com análise de strain e pela cintilografia com pirofostato (p=0,19). A prevalência de hipertensão arterial sistêmica, diabetes mellitus, dislipidemia, tabagismo e SGL reduzido não foi diferente entre os grupos. A velocidade da onda e' septal foi a única variável que apresentou diferença significativa entre os indivíduos com e sem SGL reduzido, com uma área sob a curva ROC de 0,80 (IC95% = 0,61-0,98, p = 0,027). A melhor acurácia diagnóstica foi alcançada com uma velocidade e' septal ≤ 8,5 cm/s. Não houve associação entre o tipo de variante genética e o envolvimento cardíaco pré-clínico, nem entre o uso de tafamidis e este mesmo envolvimento (37,5% versus 40,0%, p = 0,90). Conclusão: O envolvimento cardíaco subclínico foi frequente em uma amostra de carreadores da variante genética do gene TTR. Um valor do SGL reduzido foi o achado mais comum. Não houve associação entre a presença de polineuropatia amiloidótica e o envolvimento subclínico. O tipo de variante genética não foi associado com envolvimento cardíaco precoce. Nesta amostra, o uso de tafamidis (20mg/dia) não foi associado com uma menor prevalência de envolvimento cardíaco subclínico.

Abstract Background: Transthyretin amyloidosis (ATTR) is an infiltrative disease caused by abnormal protein deposition mainly in the heart and peripheral nervous system. When it affects the heart, the disease presents as restrictive cardiomyopathy; when it affects the peripheral and autonomic nervous system, it manifests as polyneuropathy, and is called familial amyloid polyneuropathy (FAP). There are two ATTR subtypes: wild-type ATTR, where there is no mutation, and mutant ATTR (ATTRm), which is characterized by a mutation in the gene encoding the transthyretin protein (TTR). In both subtypes, cardiac involvement is the major marker of poor prognosis. Objectives: To assess the prevalence of subclinical cardiac involvement in a sample of patients with TTR gene mutation by using pyrophosphate scintigraphy and strain echocardiography; to compare scintigraphy and strain findings; to evaluate the association between neurological manifestations (FAP) and subclinical cardiac involvement; and to analyze whether there is an association between any specific mutation and cardiac involvement. Methods: This is a cross-sectional study with carriers of the TTR gene mutation, without cardiovascular symptoms or changes in electrocardiographic or conventional echocardiographic parameters. All patients underwent pyrophosphate scintigraphy and strain echocardiography. Subclinical cardiac involvement was defined as a Perugini score ≥ 2, heart-to-contralateral lung (H/CL) ratio ≥ 1.5 at 1 h, H/CL ≥1.3 at 3 h, or global longitudinal strain (GLS) ≤ −17%. Descriptive and analytical analyses were performed and Fisher's exact test and Mann-Whitney test were applied. A value of p < 0.05 was considered significant. Results: The 23 patients evaluated had a median age of 51 years (IQR 37-57 years), 15 (65.2%) were female, 12 (52.2%) were Pardo, nine (39.1%) had systemic arterial hypertension, and nine (39.1%) had a previous diagnosis of FAP. Of the nine patients with FAP, 8 (34.8%) were on tafamidis. The associated mutations were Val142IIe, Val50Met, and IIe127Val. The median GLS in the sample was −19% (−16% to −20%). Of the 23 patients, nine (39.1%; 95% CI = 29-49%) met criteria for cardiac involvement, six (26%) by the GLS-based criteria only. There was no association between having FAP and being an asymptomatic carrier, as assessed by strain echocardiography and pyrophosphate scintigraphy (p = 0.19). The prevalence of systemic arterial hypertension, diabetes mellitus, dyslipidemia, smoking, and reduced GLS did not differ between groups. Septal e' wave velocity was the only variable that significantly differed between individuals with and without reduced GLS, with an area under the ROC curve of 0.80 (95% CI = 0.61-0.98, p = 0.027). The best diagnostic accuracy was achieved with a septal e' velocity ≤ 8.5 cm/s. There was no association between mutation type and preclinical cardiac involvement, nor between tafamidis use and lower degree of cardiac involvement (37.5% versus 40.0%, p = 0.90). Conclusion: Subclinical cardiac involvement was common in a sample of TTR mutation carriers without cardiac involvement. Reduced left ventricular GLS was the most frequent finding. There was no association between the presence of amyloid polyneuropathy and subclinical cardiac involvement. Type of mutation was not associated with early cardiac involvement. In this sample, the use of tafamidis 20 mg/day was not associated with a lower prevalence of subclinical cardiac involvement.

Late-onset familial amyloidosis polyneuropathy associated with c.186G>C in transthyretin.

INTRODUCTION: The most common form of hereditary amyloidosis is associated with variants of transthyretin (TTR). Familial amyloidosis polyneuropathy associated with variants of TTR (FAP-TTR) is an infrequent, multisystemic disease, with predominant involvement of the peripheral nervous system. More than 130 pathogenic variants have been identified so far and most of them are amyloidogenic, being Val30Met the most frequently described. CASE REPORT: A 74 year-old male was evaluated for progressive decreased sensitivity and associated loss of strength in four limbs in the previous two years, needing assistance for walking. Areflexia, bilateral tibialis anterior and gastrocnemius atrophy, bilateral anesthesia and apalesthesia were found in lower limbs. Bilateral hypoesthesia was reported in upper limbs. No painful dysesthesia, hyperalgesia or allodynia were found. DNA sequencing of the TTR gene led to the detection of the variant c.186G>C in heterozygous state. The resulting variant (Glu62Asp), located in the critical functional domain, has not been published before. CONCLUSION: The importance of considering late onset, sporadic FAP-TTR as a differential diagnosis of cryptogenic polyneuropathy is highlighted.

Introducción: La forma más común de amiloidosis hereditaria está asociada con variantes de la transtiretina. La polineuropatía amiloidótica familiar asociada con variantes de la TTR (FAP-TTR) es una enfermedad multisistémica poco frecuente, con afectación predominante del sistema nervioso periférico. Hasta ahora se han identificado más de 130 variantes patogénicas y la mayoría de ellas son amiloidogénicas, siendo Val30Met la más frecuentemente descrita. Caso clínico: Un paciente de 74 años fue evaluado por disminución progresiva de la sensibilidad y pérdida asociada de fuerza en las cuatro extremidades de dos años de evolución, necesitando ayuda para caminar. En las extremidades inferiores se observó arreflexia, atrofia bilateral del tibial anterior y del gastrocnemio, anestesia bilateral y apalestesia. Los miembros superiores presentaban hipoestesia bilateral. No se observaron disestesias dolorosas, hiperalgesia ni alodinia. La secuenciación del ADN del gen TTR permitió detectar la variante c.186G>C en estado heterocigoto. La variante resultante (Glu62Asp), localizada en el dominio funcional crítico de la proteína, no ha sido informada con anterioridad. Conclusión: Se destaca la importancia de considerar la FAP-TTR esporádica de aparición tardía como un diagnóstico diferencial de la polineuropatía criptogénica.

Real-life experience with inotersen at CEPARM, Hospital Universitário Clementino Fraga Filho, Universidade Federal do Rio de Janeiro / Experiência de vida-real com inotersena no CEPARM, Hospital Universitário Clementino Fraga Filho, Universidade Federal do Rio de Janeiro

Abstract Background Hereditary transthyretin amyloidosis (ATTRv) is an inherited, progressive, and fatal disease still largely underdiagnosed. Mutations in the transthyretin (TTR) gene cause the TTR protein to destabilize, misfold, aggregate, and deposit in body tissues, which makes ATTRv a disease with heterogeneous clinical phenotype. Objective To describe the long-term efficacy and safety of inotersen therapy in patients with ATTRv peripheral neuropathy (ATTRv-PN). Methods Patients who completed the NEURO-TTR pivotal study and the NEURO-TTR OLE open-label extension study migrated to the present study and were followed-up for at least 18 more months to an average of 67 months and up to 76 months since day 1 of the inotersen therapy (D1-first dose of inotersen). Disease progression was evaluated by standard measures. Results Ten ATTRv-PN patients with Val30Met mutation were included. The mean disease duration on D1 was of 3 years, and the mean age of the patients was of 46.8 years. During an additional 18-month follow up, neurological function, based on the Neuropathy Impairment Score and the Polyneuropathy Disability Score, functionality aspects (Karnofsky Performance Status), and nutritional and cardiac aspects were maintained. No new safety signs have been noted. Conclusion The treatment with inotersen was effective and well tolerated for the average of 67 months and up to 76 months. Our results are consistent with those of larger phase-III trials.

Resumo Antecedentes Amiloidose hereditária por transtirretina (ATTRv) é uma doença hereditária, progressiva e fatal ainda largamente subdiagnosticada. Mutações no gene transtirretina (TTR) promovem desestabilização, desdobramento, agregação e depósito da proteína TTR em tecidos do corpo, o que faz da ATTRv uma doença de fenótipo clínico heterogêneo. Objetivo Descrever a eficácia e segurança da terapia com inotersena no longo prazo em pacientes com neuropatia periférica ATTRv (ATTRv-PN). Métodos Pacientes que completaram o estudo pivotal NEURO-TTR e o estudo de extensão aberta NEURO-TTR OLE migraram para este estudo e foram acompanhados por no mínimo 18 meses adicionais, em média por 67 meses, e por até 76 meses, desde o dia 1 da terapia com inotersena (D1-primeira dose de inotersena). A progressão da doença foi avaliada por medidas padronizadas. Resultados Dez pacientes com ATTRv-PN com mutação Val30Met foram incluídos. A duração média da doença no D1 era de 3 anos, e a média de idade dos pacientes era de 46,8 anos. Durante o período de acompanhamento adicional de 18 meses, a função neurológica, baseada no Neuropathy Impairment Score e no Polyneuropathy Disability Score, os aspectos de funcionalidade (Karnofsky Performance Status), nutricional e cardíacos estavam mantidos. Não se observou nenhum novo sinal de segurança. Conclusão O tratamento com inotersena foi eficaz e bem tolerado por 67 meses em média, e por até 76 meses. Nossos resultados são consistentes com os de estudos maiores de fase III.

¿Qué hay de nuevo en el diagnóstico de amiloidosis? / What is new in diagnosis of amyloidosis?

La amiloidosis siempre ha representado un desafío diagnóstico. En el año 2020, el Grupo de Estudio de Amiloidosis (GEA), confeccionó la Guía de Práctica Clínica para el Diagnóstico de Amiloidosis. Nuevas líneas de investigación se han desarrollado posteriormente. Esta revisión narrativa tiene como intención explorar el estado del arte en el diagnóstico de la amiloidosis. En pacientes con amiloidosis se recomienda la tipificación de la proteína mediante espectrometría de masa, técnica de difícil ejecución por requerir de microdisectores láser para la preparación de la muestra. Algunas publicaciones recientes proponen otros métodos para obtener la muestra de amiloide que se va a analizar, permitiendo prescindir de la microdisección. Por otra parte, en pacientes con Amiloidosis ATTR confirmada, la recomendación de secuenciar el gen amiloidogénico se encontraba destinada a los casos sospechosos de ATTR hereditaria (ATTRv,), pero actualmente esta se ha extendido a todos los pacientes sin importar la edad. En lo que respecta a los estudios complementarios orientados al diagnóstico de compromiso cardíaco, se ha propuesto el uso de la inteligencia artificial para su interpretación, permitiendo la detección temprana de la enfermedad y el correcto diagnóstico diferencial. Para el diagnóstico de neuropatía, las últimas publicaciones proponen el uso de la cadena ligera de neurofilamento sérica, que también podría resultar un indicador útil para seguimiento. Finalmente, con referencia a la amiloidosis AL, la comunidad científica se encuentra interesada en definir qué características determinan el carácter amiloidogénico de las cadenas livianas. La N-glicosilación de dichas proteínas impresiona ser uno de los determinantes en cuestión. (AU)

Amyloidosis has always represented a diagnostic challenge. In 2020, the Amyloidosis Study Group (ASG) developed the "Clinical Practice Guideline for the Diagnosis of Amyloidosis". New lines of research have subsequently emerged. This narrative review aims to explore the state of the art in the diagnosis of amyloidosis diagnosis. In patients with amyloidosis, protein typing by mass spectrometry is recommended, a technique hard to perform because it requires laser microdissection for sample preparation. Recent publications propose other methods to obtain the amyloid sample to be analyzed, making it possible to dispense with microdissection. On the other hand, in patients with confirmed TTR amyloidosis (aTTR), the recommendation to sequence the amyloidogenic gene was intended for suspected cases of hereditary aTTR but has now been extended to all patients regardless of age. (AU)

[Neurological manifestations of ATTR amyloidosis]. / Neurologische Manifestationen der ATTR-Amyloidose.

Transthyretin amyloidosis (ATTR) is a rare disease in which the protein transthyretin (TTR) is deposited in the form of amyloid fibrils in various tissues and organs and secondarily leads to functional impairment, especially in peripheral nerves and the heart. A differentiation is made between hereditary and sporadic forms. The hereditary variant is inherited in an autosomal dominant manner and usually occurs in the younger to middle-aged, while the sporadic form occurs in older age and has no known genetic cause. Typical signs of hereditary ATTR amyloidosis (ATTRv, v for variant) include a rapidly progressing sensorimotor and autonomic polyneuropathy (PNP), cardiac dysfunction as well as ocular and gastrointestinal symptoms. A carpal tunnel syndrome often precedes the manifestation. Various options (tafamidis, patisiran, inotersen or vutrisiran) are available for the treatment of patients with ATTRv with PNP in Germany, depending on the severity. In the sporadic variant of wild-type ATTR amyloidosis (ATTRwt), symptoms of progressive cardiomyopathy are usually prominent; however, neurological assessment of these patients often also reveals a concomitant sensory ataxic PNP. The tetramer stabilizer tafamidis can be used for treatment. Because of this complex presentation, the management of patients with ATTR amyloidosis should be performed in interdisciplinary centers specialized in amyloidosis.

Brazilian consensus for diagnosis, management and treatment of hereditary transthyretin amyloidosis with peripheral neuropathy: second edition / Consenso brasileiro para o diagnóstico, manejo e tratamento da polineuropatia amiloidótica familiar associada à transtirretina: segunda edição

Abstract Hereditary transthyretin amyloidosis with peripheral neuropathy (ATTRv-PN) is an autosomal dominant inherited sensorimotor and autonomic polyneuropathy with over 130 pathogenic variants identified in the TTR gene. Hereditary transthyretin amyloidosis with peripheral neuropathy is a disabling, progressive and life-threatening genetic condition that leads to death in ~ 10 years if untreated. The prospects for ATTRv-PN have changed in the last decades, as it has become a treatable neuropathy. In addition to liver transplantation, initiated in 1990, there are now at least 3 drugs approved in many countries, including Brazil, and many more are being developed. The first Brazilian consensus on ATTRv-PN was held in the city of Fortaleza, Brazil, in June 2017. Given the new advances in the area over the last 5 years, the Peripheral Neuropathy Scientific Department of the Brazilian Academy of Neurology organized a second edition of the consensus. Each panelist was responsible for reviewing the literature and updating a section of the previous paper. Thereafter, the 18 panelists got together virtually after careful review of the draft, discussed each section of the text, and reached a consensus for the final version of the manuscript.

Resumo Polineuropatia amiloidótica familiar associada a transtirretina (ATTRv-PN) é uma polineuropatia sensitivo-motora e autonômica hereditária autossômica dominante com mais de 130 variantes patogênicas já identificadas no gene TTR. A ATTRv-PN é uma condição genética debilitante, progressiva e que ameaça a vida, levando à morte em ~ 10 anos se não for tratada. Nas últimas décadas, a ATTRv-PN se tornou uma neuropatia tratável. Além do transplante de fígado, iniciado em 1990, temos agora 3 medicamentos modificadores de doença aprovados em muitos países, incluindo o Brasil, e muitas outras medicações estão em desenvolvimento. O primeiro consenso brasileiro em ATTRv-PN foi realizado em Fortaleza em junho de 2017. Devido aos novos avanços nesta área nos últimos 5 anos, o Departamento Científico de Neuropatias Periféricas da Academia Brasileira de Neurologia organizou uma segunda edição do consenso. Cada panelista ficou responsável por rever a literatura e atualizar uma parte do manuscrito. Finalmente, os 18 panelistas se reuniram virtualmente após revisão da primeira versão, discutiram cada parte do artigo e chegaram a um consenso sobre a versão final do manuscrito.

[Systemic forms of amyloidosis with cardiac manifestation]. / Systemische Amyloidoseformen mit kardialer Manifestation.

The term amyloidosis summarizes heterogeneous diseases in which a misfolding of protein structures occurs. These misfolded proteins can fundamentally be deposited anywhere in the body and lead to malfunction of the affected organ. There are preferential sites of deposition depending on which protein is misfolded. Cardiac transthyretin (ATTR) amyloidosis is a rare cause of cardiomyopathy and part of an underdiagnosed systemic disease. For cardiac ATTR amyloidosis, which involves deposition of misfolded tranthyretin either as a wild type (wtATTR) or as a mutated form (mATTR or hATTR), evidence-based treatment options have recently become available with slowing of the progression of the cardiomyopathy and a significant reduction of hospitalization rates. Therefore, it is important to diagnose this severe disease at an early stage and to differentiate it from other forms of amyloidosis. A clinical screening is easily possible by determination of free light chains using imaging examinations (cardiac magnetic resonance imaging or scintigraphic procedures) and immunofixation before the definitive diagnosis is made based on a biopsy and/or genetic tests. An interdisciplinary work-up involving hemato-oncology, nephrology, neurology and other disciplines, is indispensable when cardiac amyloidosis is suspected.

Clinical, genetic characteristics and follow-up in 14 patients with transthyretin familial amyloid polyneuropathy / 中华神经科杂志

Objective:To summarize the clinical and genetic characteristics in patients with transthyretin familial amyloid polyneuropathy (TTR-FAP).Methods:Fourteen unrelated TTR-FAP patients diagnosed at Xuanwu Hospital, Capital Medical University from September 2014 to February 2022 were retrospectively reviewed. The clinical manifestation, electrophysiology, cardiac function, biopsy and gene mutation were analyzed.Results:In the 14 patients (13 males, 1 female) diagnosed as TTR-FAP, the mean age at onset was 53.9 years (range: 33.0-71.0 years), with a mean course from symptom-onset to diagnosis of 4.1 years. The late-onset type occurred in 9 cases. Seven patients had a family history of TTR-FAP. Distal paresthesia of lower limbs was the commonest initial symptom (8 cases), with sensorimotor neuropathy and autonomic dysfunction seen initially in 4 and 2 cases, respectively. Cardiac involvement occurred in 6/8 of the patients. Nerve conduction studies indicated extremely axonal impairment with demyelinating features. Sural nerve biopsies showed moderate to severe axonal loss of myelinated fibers and the positive rate of Congo red staining was 8/14. Of 8 different TTR mutations detected, V50M was the most common (appearing in 5 cases). No obvious neuropathy progression was seen in the 5 patients who received tafamidis and 2 patients died of dyscrasia. Conclusions:TTR-FAP is more common in males, with sensorimotor axonal polyneuropathy, autonomic dysfunction and cardiac subclinical damage as the predominant symptoms. V50M is the commonest mutation. Tafamidis can delay the progression of disability.

Riesgos potenciales de la estimulación nerviosa eléctrica cubital para monitorización de la transmisión neuromuscular: reporte de un caso de polineuropatía amiloidótica familiar / Pitfalls of cubital electrical nerve stimulation for neuromuscular transmission monitoring: a case report of familial amyloid polyneuropathy

La polineuropatía amiloidótica familiar (PAF) por transtiretina es una enfermedad dominante autosómica rara que provoca depósitos sistémicos de amiloides. Afecta al sistema nervioso y se caracteriza por neuropatía progresiva de tipo sensorial, motora y autonómica. Los pacientes con PAF requieren a menudo cirugía y cuidados anestésicos para transplante hepático e implantación de cardioversores-desfibriladores/marcapasos. La neuropatía periférica es un hallazgo común, aunque no existen casos reportados sobre su interferencia en la monitorización de la transmisión neuromuscular de la anestesia. Reportamos el caso de un paciente con PAF en el que la falta de concienciación y los factores de distracción condujeron a la malinterpretación de la monitorización neuromuscular y originaron sedación y ventilación innecesarias en la unidad de cuidados post-anestésicos. PAF puede interferir con la monitorización neuromuscular habitual del nervio cubital. Los anestesiólogos deben estar al tanto del compromiso neuromuscular potencial para encontrar la mejor localización de la monitorización en cada paciente. En este caso sugammadex fue seguro y fiable para el antagonismo del bloqueo neuromuscular del rocuronio, a pesar de la falta de monitorización cuantitativa adecuada.(AU)

Transthyretin familial amyloid polyneuropathy (FAP) is a rare autosomal dominant disease that provokes systemic deposition of amyloid. It affects the nervous system and it is characterized by progressive sensory, motor, and autonomic neuropathy. Patients with FAP often require surgery and anesthetic care for hepatic transplantation and cardioverter-defibrillator/pacemaker implantation. Peripheric neuropathy is a common finding, but there are no reported cases of its interference with anesthetic neuromuscular transmission monitoring. We report a case of a FAP patient where lack of awareness and distracting factors led to misinterpretation of neuromuscular monitoring and unnecessary sedation and ventilation in the post anesthetic care unit. FAP may interfere with the usual cubital nerve neuromuscular monitoring. Anesthesiologists should be aware of potential neuromuscular compromise to find the best monitoring location for each patient. Sugammadex was safe and reliable in the antagonism of rocuronium neuromuscular blockade in this case, despite the lack of adequate quantitative monitoring.(AU)

Pitfalls of cubital electrical nerve stimulation for neuromuscular transmission monitoring: A case report of familial amyloid polyneuropathy.

Transthyretin familial amyloid polyneuropathy (FAP) is a rare autosomal dominant disease that provokes systemic deposition of amyloid. It affects the nervous system and it is characterized by progressive sensory, motor, and autonomic neuropathy. Patients with FAP often require surgery and anesthetic care for hepatic transplantation and cardioverter-defibrillator/pacemaker implantation. Peripheric neuropathy is a common finding, but there are no reported cases of its interference with anesthetic neuromuscular transmission monitoring. We report a case of a FAP patient where lack of awareness and distracting factors led to misinterpretation of neuromuscular monitoring and unnecessary sedation and ventilation in the post anesthetic care unit. FAP may interfere with the usual cubital nerve neuromuscular monitoring. Anesthesiologists should be aware of potential neuromuscular compromise to find the best monitoring location for each patient. Sugammadex was safe and reliable in the antagonism of rocuronium neuromuscular blockade in this case, despite the lack of adequate quantitative monitoring.

The Frequency of V122I Transthyretin Mutation in a Cohort of African American Individuals With Bilateral Carpal Tunnel Syndrome.

Introduction: Hereditary transthyretin amyloidosis (hATTR) can cause multisystem organ disorders including polyneuropathy and cardiomyopathy. Amongst the many known pathologic mutations of the transthyretin (TTR) gene, the Val122Ile (V122I) mutation can be found in 3-4% of African Americans. Up to 47% of patients with the V122I hATTR cardiomyopathy had a history of carpal tunnel syndrome (CTS). This raises the question should we screen for this mutation in African Americans with bilateral CTS for the purpose of preventing advanced disease associated with hATTR. This is a prospective pilot study to determine the likelihood of African Americans with bilateral CTS having the V122I mutation and whether various clinical factors contribute to that probability. Methodology: Adult African American patients without prior history of amyloidosis diagnosed with bilateral CTS were recruited for the study. They received genetic testing to screen for a TTR mutation. They also completed questionnaires to screen for symptoms of cardiomyopathy and neuropathy, other risk factors for CTS, and family history of CTS and cardiomyopathy. Result: Two of the sixteen patients (12.5%) in this cohort were found to have the V122I mutation. The absence of polyneuropathy and cardiomyopathy symptoms, presence of other CTS risk factors, and absence of family history of CTS and cardiomyopathy did not decrease the likelihood of V122I mutation in this cohort. Conclusion: The frequency of V122I transthyretin mutation in African Americans with bilateral CTS may be higher than 3-4%. The presence of bilateral CTS alone may be a justification to screen for TTR mutation in this population.

Expert opinion on monitoring symptomatic hereditary transthyretin-mediated amyloidosis and assessment of disease progression.

BACKGROUND: Hereditary transthyretin-mediated amyloidosis, also known as ATTRv amyloidosis (v for variant), is a rare, autosomal dominant, fatal disease, in which systemic amyloid progressively impairs multiple organs, leading to disability and death. The recent approval of disease-modifying therapies offers the hope of stabilization or eventual reversal of disease progression, and yet highlights a lack of disease-management guidance. A multidisciplinary panel of expert clinicians from France and the US came to consensus on monitoring the disease and identifying progression through a clinical opinion questionnaire, a roundtable meeting, and multiple rounds of feedback. MONITORING DISEASE AND PROGRESSION: A multidisciplinary team should monitor ATTRv amyloidosis disease course by assessing potential target organs at baseline and during follow-up for signs and symptoms of somatic and autonomic neuropathy, cardiac dysfunction and restrictive cardiomyopathy, and other manifestations. Variability in penetrance, symptoms, and course of ATTRv amyloidosis requires that all patients, regardless of variant status, undergo regular and standardized assessment in all these categories. Progression in ATTRv amyloidosis may be indicated by: worsening of several existing quantifiable symptoms or signs; the appearance of a new symptom; or the worsening of a single symptom that results in a meaningful functional impairment. CONCLUSIONS: We suggest that a multisystem approach to monitoring the signs and symptoms of ATTRv amyloidosis best captures the course of the disease. We hope this work will help form the basis of further, consensus-based guidance for the treatment of ATTRv amyloidosis.

Pitfalls of cubital electrical nerve stimulation for neuromuscular transmission monitoring: a case report of familial amyloid polyneuropathy. / Riesgos potenciales de la estimulación nerviosa eléctrica cubital para monitorización de la transmisión neuromuscular: reporte de un caso de polineuropatía amiloidótica familiar.

Transthyretin familial amyloid polyneuropathy (FAP) is a rare autosomal dominant disease that provokes systemic deposition of amyloid. It affects the nervous system and it is characterized by progressive sensory, motor, and autonomic neuropathy. Patients with FAP often require surgery and anesthetic care for hepatic transplantation and cardioverter-defibrillator/pacemaker implantation. Peripheric neuropathy is a common finding, but there are no reported cases of its interference with anesthetic neuromuscular transmission monitoring. We report a case of a FAP patient where lack of awareness and distracting factors led to misinterpretation of neuromuscular monitoring and unnecessary sedation and ventilation in the post anesthetic care unit. FAP may interfere with the usual cubital nerve neuromuscular monitoring. Anesthesiologists should be aware of potential neuromuscular compromise to find the best monitoring location for each patient. Sugammadex was safe and reliable in the antagonism of rocuronium neuromuscular blockade in this case, despite the lack of adequate quantitative monitoring.

Condutas clínicas e barreiras no tratamento da polineuropatia amiloidótica familiar associada à transtirretina (PAF-TTR) no Brasil / Clinical practice and barriers in familial transthyretinrelated amyloidotic polyneuropathy (FAP) care in Brazil

Objetivo: Identificar as condutas terapêuticas e a variabilidade na prática clínica, assim como necessidades não atendidas e barreiras para a adequada assistência a pacientes com polineuropatia amiloidótica familiar relacionada à transtirretina (PAF-TTR), no Brasil. Métodos: Estudo transversal, por meio de questionário semiestruturado on-line enviado por e-mail. Foram incluídos médicos com experiência no manejo clínico-assistencial de pacientes com PAF-TTR no Brasil. O questionário foi composto por 30 questões envolvendo características gerais da população brasileira com PAF-TTR, características das escolhas terapêuticas e da falha, definições de progressão de doença e estadiamento, e métodos para mensuração do impacto na qualidade de vida. Resultados: Seis profissionais responderam ao inquérito. Quanto ao diagnóstico e à classificação da doença, houve consenso quanto ao uso de quadro clínico associado a testagem genética para o diagnóstico, e foram considerados adequados os critérios de Coutinho e do Ministério da Saúde, apesar de serem pouco úteis na avaliação da progressão da doença. Entre os especialistas, 83,3% entendem que a terapia atualmente disponível no Sistema Único de Saúde (SUS) atende às necessidades dos pacientes no estágio I da doença, entretanto todos os especialistas apontam necessidades assistenciais não atendidas, uma vez que esse medicamento não possui benefício definido para os estágios II e III da doença. A progressão da doença é definida como qualquer novo sintoma ou piora daqueles preexistentes, não sendo necessária modificação no estágio da doença para caracterizar tal evento. Conclusões: A condução deste estudo permitiu a identificação de aspectos importantes para auxiliar no entendimento da prática clínico-assistencial no país e das necessidades em saúde desses pacientes

Objective: To identify therapeutic approaches and variability in clinical practice, as well as unmet needs and barriers to adequate care for patients with familial transthyretin-related amyloidotic polyneuropathy (FAP) in Brazil. Methods: Cross-sectional study using an online semi-structured questionnaire sent by email. Physicians with experience in the clinical-care management of patients with FAP in Brazil were included. The questionnaire consisted of 30 questions involving general characteristics of the Brazilian population with FAP; characteristics of therapeutic choices and failure; definitions of disease progression and staging; and methods for measuring the impact on quality of life. Results: Six professionals responded to the survey. As for the diagnosis and classification of the disease, there was a consensus regarding the use of a clinical picture associated with genetic testing for the diagnosis and, as appropriate, the criteria proposed by Coutinho and the Ministry of Health, although not very useful in evaluating the progression of the disease. 83.3% of experts understand that the therapy currently available in the SUS meets the needs of patients in stage I of the disease, however, all experts point out unmet care needs, since this drug has no defined benefit for stages II and III of the disease. Disease progression is defined as any new symptom or worsening of pre-existing ones, and no change in the stage of the disease is necessary to characterize such an event. Conclusions: The conduction of this study allowed to identify important aspects to a better understanding of the clinical care practice in the country and unmet needs of these patients

Hereditary Transthyretin Amyloidosis- Clinical and Genetic Characteristics of a Multiracial South-East Asian Cohort in Singapore.

BACKGROUND AND AIMS: Studies of hereditary transthyretin amyloidosis (ATTRv amyloidosis) in South-East Asia are underrepresented in the literature. We report the unique phenotypic and genetic characteristics of this disorder in a multiracial South-East Asian cohort. METHODS: Patients with genetically proven ATTRv amyloidosis were identified over a 13-year period (2007-2020) at the National Neuroscience Institute, Singapore. Clinical, laboratory, genotypic and electrophysiological features were retrospectively reviewed. RESULTS: 29 patients comprising Chinese, Malay, Burmese, Vietnamese and Indonesians with ATTRv amyloidosis were identified. Somatic neuropathy was the most common initial presentation, followed by carpal tunnel syndrome, autonomic dysfunction and cardiac dysfunction. ATTR-A97S (p.Ala117Ser) was the most common variant found in 14 patients, constituting 66.7%of ethnic Chinese patients and 48.3%of the entire cohort. Five patients had early-onset disease (age < 50 years) with the following variants: ATTR-V30M (p.Val50Met), ATTR-G47A (p.Gly67Ala), ATTR-S50I (p.Ser70Ile) and ATTR-A97S (p.Ala117Ser); one patient with ATTR-A97S (p.Ala117Ser) had isolated unilateral carpal tunnel syndrome with amyloid deposits identified on histological examination of the transverse carpal ligament. All early-onset patients had a positive parental history; two patients, with ATTR-S50I (p.Ser70Ile) and ATTR-Ala97Ser (p.Ala117Ser) respectively, demonstrated anticipation with mother-to-daughter inheritance. Amongst the 24 patients with late-onset disease (age≥50 years), two patients had novel variants, ATTR-G66D (p.Glu86Asp) and ATTR-A81V (p.Ala101Val) that were confirmed to be pathogenic based on the histological identification of transthyretin amyloid. Other identified variants included ATTR-V30M (p.Val50Met), ATTR-R34T (p.Arg54Thr), ATTR-S50I (p.Ser70Ile), ATTR-H88R (p.His108Arg) and ATTR-A97S (p.Ala117Ser). CONCLUSION: Our study further expands the genotypic and phenotypic knowledge regarding ATTRv amyloidosis.

Evolución a mediano plazo de pacientes con diagnóstico de cardiopatía amiloidótica por transtiretina / Mid-term Outcome of Patients with Diagnosis of Transthyretin Cardiac Amyloidosis

RESUMEN Introducción: El compromiso cardíaco es la principal causa de morbimortalidad en la amiloidosis, independientemente de la patogenia productora del amiloide subyacente. La amiloidosis por transtiretina (TTR) es una de las variantes más frecuentes, por lo cual el objetivo de este trabajo fue evaluar las características de una cohorte de pacientes con diagnóstico de cardiopatía amiloidótica por TTR (CA-TTR) Material y métodos: Se recabaron datos de los estudios basales, de la metodología diagnóstica y de la evolución de 49 pacientes en seguimiento en la Clínica de Miocardiopatías de nuestra institución. Resultados: La mediana del tiempo de seguimiento fue de 1258 días (410-2004) y la edad promedio de 79 ± 9 años. Al inicio del seguimiento, el 57% de los pacientes estaban en clase funcional I, el 26%, en II y el 16%, en III-IV. El diagnóstico se basó en centellograma con difosfonatos en el 92%; en el 24% requirió biopsia. La mortalidad global fue del 19%, con 15% de muerte cardiovascular. La tasa de internación por insuficiencia cardíaca fue 29%; el 63% de los pacientes empeoró su clase funcional. Conclusiones: El seguimiento de nuestros pacientes con CA-TTR expresa los cambios que ha sufrido el proceso diagnóstico, con una reducción de estudios invasivos y tiempo para la caracterización. El diagnóstico de pacientes en etapas "tempranas" de la enfermedad parece impactar en los resultados a mediano plazo.

ABSTRACT Background: Cardiac involvement is the main cause of morbidity and mortality in amyloidosis, regardless of the underlying pathogenesis of amyloid production, and transthyretin (TTR) amyloidosis is one of the most frequent variants. Objective: The aim of this study was thus to assess the characteristics of a cohort of patients with diagnosis of TTR cardiac amyloidosis (ATTR-CA). Methods: Baseline data and diagnostic and follow-up methodology were collected from 49 patients treated at the cardiomy-opathy clinic of our institution. Results: Median follow-up was 1,258 days (410-2004). Mean age was 79±9 years, and 57% of patients were in functional class (FC) I, 26% in FC II and 16% in FC III-IV at follow-up onset. Diagnosis was made with diphosphonate scintigraphy in 92% of patients and 24% required a biopsy. Overall mortality was 19%, with 15% of cardiovascular death. The rate of hospitalization for heart failure was 29% and 63% of patients worsened their FC. Conclusions: Follow-up of patients with ATTR-CA expresses the changes undergone by the diagnostic process, with a reduction of invasive studies and time to characterization. The diagnosis of patients at "early stages of the disease" seems to have an impact on mid-term outcomes.

Amyloid Proteins and Peripheral Neuropathy.

Painful peripheral neuropathy affects millions of people worldwide. Peripheral neuropathy develops in patients with various diseases, including rare familial or acquired amyloid polyneuropathies, as well as some common diseases, including type 2 diabetes mellitus and several chronic inflammatory diseases. Intriguingly, these diseases share a histopathological feature-deposits of amyloid-forming proteins in tissues. Amyloid-forming proteins may cause tissue dysregulation and damage, including damage to nerves, and may be a common cause of neuropathy in these, and potentially other, diseases. Here, we will discuss how amyloid proteins contribute to peripheral neuropathy by reviewing the current understanding of pathogenic mechanisms in known inherited and acquired (usually rare) amyloid neuropathies. In addition, we will discuss the potential role of amyloid proteins in peripheral neuropathy in some common diseases, which are not (yet) considered as amyloid neuropathies. We conclude that there are many similarities in the molecular and cell biological defects caused by aggregation of the various amyloid proteins in these different diseases and propose a common pathogenic pathway for "peripheral amyloid neuropathies".