¿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)

Polineuropatía por amiloidosis por transtiretina de inicio tardío. Caso clínico / Late-onset hereditary transthyretin amyloidosis with polyneuropathy. Report of one case

Hereditary transthyretin amyloidosis is a multisystemic autosomal dominant genetic disorder characterized by progressive distal sensory-motor polyneuropathy or restrictive cardiomyopathy, secondary to amyloid deposits. Its pathogenesis lies in the TTR gene mutation, and the Val50Met mutation is the most frequent. Patients have significant differences in the onset and severity of clinical presentation according to their country of origin. The diagnosis of this pathology is complex, even more in countries where it is not considered endemic. However, early suspicion and management are essential to improve survival and avoid unnecessary diagnostic and therapeutic strategies. We report a 69-year-old woman who presented a sensory-motor polyneuropathy, predominantly sensory, associated with distal neuropathic pain and bilateral vitritis. The history of her Italian father with polyneuropathy of unspecified etiology stood out. A vitreous biopsy identified amyloid substance deposits (congo red positive). These were also confirmed on a superficial peroneal nerve biopsy. During the etiological study of her polyneuropathy, an increased Kappa/Lambda index of 2.55 mg/L stood out. Therefore, light chain amyloidosis was suspected, and chemotherapy treatment was indicated without favorable response. After 10 years of progressive neurological and ophthalmological involvement, a genetic study confirmed the first case of late-onset hereditary transthyretin amyloidosis Val50Met with polyneuropathy in Chile.

Familial amyloid polyneuropathy: a proposal for an epidemiological study through the creation of a virtual platform / Polineuropatia amiloidótica familiar: uma proposta de estudo epidemiológico por meio da criação de uma plataforma virtual

Amyloidosis are characterized by mutations in the gene coding for transthyretin (TTR), located on chromosome 18. TTR is a set of four 127-aminoacid polypeptides structured as homotetrameric protein of 56 kDa with a secondary ß sheet structure. It plays the role of thyroxin (T4) carrier, and has a binding domain for retinol (vitamin A). It is synthesized in the liver, although a small quantity is also produced by the choroid plexus, and retinal cells. Mutations of this gene result in loss of tetramer stability. Insoluble amyloid fibrils (AF) are formed and deposited in tissues and organs. The abnormal aggregation of TTR protein trigger several syndromes, such as familial amyloid polyneuropathy (FAP-TTR), cardiomyopathies (CMP), and senile systemic amyloidosis (SSA). It is estimated there are 5,000 to 10,000 cases of FAP-TTR globally. OBJECTIVE: The study intends to develop an online platform for the diagnosis of FAP-TTR. The aim is to facilitate the diagnosis process and promote a tool for epidemiological study. METHODS: The project was based on a literature review featuring clinical and epidemiological evidence for the development of a practical platform (applied research). RESULTS: It was elaborated a platform containing a questionnaire to allow a more dynamic, cheaper, and efficient operation, mediated by a better characterization of the disease to enable its early diagnosis. CONCLUSION: The platform might become a valuable resource for the characterization, diagnosis, and future epidemiological study of FAP-TTR

As amiloidoses se caracterizam por mutações no gene codificante da transtirretina (TTR) no cromossomo 18. A proteína TTR compõe-se de uma corrente de polipeptídios de 127 resíduos, que constituem uma proteína homotetramérica de 56kDa com estrutura secundária de folha ß, que serve como proteína de deslocamento para a tiroxina (T4), e uma proteína de ligação ao retinol (vitamina A). O principal local de produção dessa proteína é o fígado, embora uma pequena quantidade seja produzida pelo plexo coroide e pelas células retinianas. O gene codificante da TTR (18q11.2-12) é pequeno (7 kb) e contém quatro éxons. As mutações convertem-se em perda do equilíbrio do tetrâmero proteico. Surgem assim, fibrilas amiloides (FA) em cadeias não ramificadas de 10 a 12 nm de diâmetro e fibrilas indissolúveis, que se condensam nos tecidos e órgãos. As síndromes concernentes ao acúmulo da proteína TTR são: polineuropatia amiloidótica familiar (PAFTTR), miocardiopatias (MCP) e amiloidose sistêmica senil (ASS). Estimativa recente relatou a existência de 5.000 a 10.000 casos de PAFTTR no mundo. OBJETIVO: O estudo objetiva elaborar uma plataforma de diagnóstico PAFTTR on-line para auxiliar como ferramenta de contribuição para o estudo da epidemiologia e facilitar o diagnóstico. MÉTODOS: O projeto baseou-se em uma pesquisa bibliográfica capaz de levantar evidências clínicas e epidemiológicas na elaboração de uma plataforma facilitadora (pesquisa aplicada). RESULTADOS: O resultado alcançado foi a elaboração da plataforma contendo um questionário, que tornará o trabalho dos profissionais mais dinâmico, barato e eficiente, caracterizando melhor a doença e promovendo um diagnóstico precoce. CONCLUSÃO: A plataforma poderá tornar-se recurso valioso para caracterização, diagnóstico e futuro estudo epidemiológico da PAF-TTR

Cardiomiopatía amiloídea por transtiretina: diagnóstico y manejo en la actualidad / Transthyretin amyloid cardiomyopathy: a review

RESUMEN: La cardiomiopatía amiloide por transtiretina (CATTR) es una enfermedad caracterizada por depósito extracelular de fibrillas amiloides en el miocardio, a partir de transtiretina mal plegada, generando una miocardiopatía restrictiva. Esta proteína mal plegada puede tener origen hereditario o adquirido, siendo más frecuente en adultos mayores. La CA-TTR ha surgido como una causa subdiagnosticada de insuficiencia cardíaca con fracción de eyección preservada (IC FEp). El pilar fundamental para su diagnóstico es la alta sospecha clínica, basada en diversas banderas de alerta ya que la sintomatología que provoca suele ser inespecífica. Como veremos en esta revisión, el diagnóstico puede sustentarse con la cintigrafía ósea, reservando para situaciones particulares la toma de biopsia. Con el advenimiento de nuevas terapias que impactan en la sobrevida de esta enfermedad, el tiempo para realizar el diagnóstico certero y la diferenciación de otras causas de amiloidosis cardíaca como la de cadenas livianas, se ha tornado crucial.

ABSTRACT: Transthyretin amyloid cardiomyopathy (AT-TR-CM) is a disease characterized by extracellular deposition of amyloid fibrils in the myocardium, from misfolded transthyretin, generating a restrictive cardiomyopathy. This misfolded protein may be inherited or acquired, and is more prevalent in elderly patients. ATTR-CM has emerged as an underdiagnosed cause of heart failure with preserved ejection fraction (HF-PEF). The fundamental pillarfor its diagnosis is high clinical suspicion since the symptoms are usually nonspecific. The diagnosis can be made from bone scintigraphy, reserving myocardial biopsy for particular situations. With the advent of new therapies that affect the survival of these patients, a timely diagnosis has become crucial.

Baseline disease characteristics in Brazilian patients enrolled in Transthyretin Amyloidosis Outcome Survey (THAOS) / Características da polineuropatia amiloidotica familiar ligada à transtirretina em pacientes brasileiros participantes do "Transthyretin Amyloidosis Outcome Survey (THAOS)"

ABSTRACT Transthyretin amyloidosis (ATTR) is characterized by the deposit of mutant or wild-type transthyretin that forms amyloid fibrils, which are extracellularly deposited within tissues and organs. Clinical manifestations of familial amyloid polyneuropathy vary according to the mutation, age at onset and geographical location. This study aimed to describe baseline disease characteristics of Brazilian patients with transthyretin familial amyloid polyneuropathy (ATTR-FAP) enrolled in the Transthyretin Amyloidosis Outcome Survey (THAOS). Methods: The THAOS is an international, noninterventional, longitudinal, observational, web-based registry designed to characterize ATTR. The outcome measures included demographics (age at symptom onset, gender, time from onset of symptoms to diagnosis, family history), genotype, and clinical characteristics (presence of amyloid deposit, frequency of misdiagnosis, presenting symptomatology). The analysis was conducted in a dataset from Brazilian patients (from November 2008 to January 2016). Results: One hundred and sixty participants (52.5% male) were included in the analysis. The majority of participants (90.6%) reported a positive family history of ATTR-FAP Median age at symptom onset was 32.5 years. Val30Met mutation was found in 91.9%. Misdiagnosis was observed in 26.6% of symptomatic patients. Over one-third (35.3%) of the misdiagnosed patients experienced a delay of more than one year before receiving a correct diagnosis. At presentation, 79.7% of the patients had motor, 87.5% sensory and 93.8% autonomic symptoms. Conclusion: ATTR-FAP in Brazil starts early, has a strong family history and the majority has Val30Met mutation. Misdiagnosis is common and the most common presentation is of a sensorimotor and autonomic neuropathy.

RESUMO Amiloidose ligada à transtirretina (ATTR) é caracterizada por depósito de transtirretina que forma fibrilas amiloides, que são depositadas extracelularmente dentro de tecidos e órgãos. As manifestações clínicas de polineuropatia amiloidótica familiar (ATTR-PAF) variam de acordo com a mutação, idade de início e localização geográfica. Este estudo tem como objetivo descrever as características dos pacientes com ATTR no Brasil, com base nos dados coletados no THAOS. Métodos: THAOS é um registro internacional longitudinal observacional desenhado para caracterizar ATTR. As medidas de desfecho incluíram dados demográficos (idade do início dos sintomas, gênero, tempo do início dos sintomas até diagnóstico, histórico familiar), genotipagem e características clínicas (presença de depósito amiloide, frequências de diagnósticos errôneos, sintomatologia presente). Esta analise foi conduzida com dados de pacientes brasileiros registrados no THAOS de Novembro 2008 a Janeiro de 2016. Resultado: Cento e sessenta pacientes (52,5% homens) foram incluídos na análise. Na maioria dos casos (90,6%) observou-se história familiar positiva de ATTR-FAP A idade média de inicio dos sintomas foi 32,5 anos. A mutação Val30Met foi encontrada em 91,9%. Erros diagnósticos foram observados em 26,6% dos casos sintomáticos. Aproximadamente um terço dos pacientes diagnosticados erroneamente tiveram atraso de mais de um ano para receber um diagnostico correto. No momento do diagnóstico 79,7% dos pacientes possuíam sintomas motores, 87,5% sintomas sensitivos e 93,8% sintomas autonômicos. Conclusão: No brasil a ATTR-FAP tem início precoce, historia familiar fortemente positiva e em sua maioria são portadores da mutação Val30Met. Erros diagnósticos são comuns e a apresentação mais comum é polineuropatia sensitivo-motora com disautonomia.

Brazilian consensus for diagnosis, management and treatment of transthyretin familial amyloid polyneuropathy / Consenso Brasileiro para o diagnóstico, manejo e tratamento da Polineuropatia Amiloidótica Familiar associada à Transtirretina

ABSTRACT Transthyretin familial amyloid polyneuropathy is an autosomal dominant inherited sensorimotor and autonomic polyneuropathy, which if untreated, leads to death in approximately 10 years. In Brazil, liver transplant and tafamidis are the only disease-modifying treatments available. This review consists of a consensus for the diagnosis, management and treatment for transthyretin familial amyloid polyneuropathy from the Peripheral Neuropathy Scientific Department of the Brazilian Academy of Neurology. The first and last authors produced a draft summarizing the main views on the subject and emailed the text to 10 other specialists. Relevant literature on this subject was reviewed by each participant and used for the individual review of the whole text. Each participant was expected to review the text and send a feedback review by e-mail. Thereafter, the 12 panelists got together at the city of Fortaleza, discussed the controversial points, and reached a consensus for the final text.

RESUMO Polineuropatia amiloidótica familiar é uma polineuropatia sensitivo-motora e autonômica de herança autossômica dominante, que caso não seja tratada leva a morte em aproximadamente 10 anos. O transplante de fígado e o tafamidis são os únicos tratamentos disponíveis no Brasil. Essa revisão consiste em um consenso do Departamento Científico de Neuropatias Periféricas da Academia Brasileira de Neurologia. O primeiro e último autores produziram um texto resumindo os principais aspectos sobre o tema e enviaram para os outros 10 especialistas por email. A literatura relevante sobre o assunto foi revisada por cada participante e utilizada para revisão individual do texto. Foi esperado que cada participante revisasse o texto e enviasse suas sugestões por e-mail. Finalmente, os 12 panelistas se encontraram na cidade de Fortaleza para discutir os pontos controversos e chegar a um consenso sobre texto final.

Mid- and long-term anxiety levels associated with presymptomatic testing of Huntington's Disease, Machado-Joseph Disease, Machado-Joseph disease, and familial amyloid polyneuropathy

Objective: To study anxiety as a variable of the mid- and long-term psychological impact of pre-symptomatic testing for three autosomal dominant late-onset disorders – Huntington’s disease (HD), Machado-Joseph disease (MJD) and familial amyloid polyneuropathy (FAP) TTR V30M – in a Portuguese sample. Methods: This cross-sectional study included 203 participants: 170 (83.7%) underwent pre-symptomatic testing for FAP, 29 (14.3%) for HD, and 4 (2%) for MJD. Of the 203 participants, 73 (36.0%) were asymptomatic carriers, 29 (14.5%) were symptomatic carriers, 9 (4.5%) were diagnosed with FAP and had a liver transplant, and 89 (44.5%) were non-carriers. Most were women (58.1%) and married (66.5%). The anxiety variable was assessed using the Zung Self-Rating Anxiety Scale (SAS). Results: The anxiety scores were higher for symptomatic carriers and for those who underwent psychological support consultations over the years. For symptomatic carriers, the mean scores were superior to 40 points, which reflects clinical anxiety. Conclusion: Although it was not possible to differentiate between the mid- and long-term psychological impacts, this study supports the conclusion that the proximity to the age of symptoms onset might be a trigger for anxiety.

Clinical features and outcomes of systemic amyloidosis with gastrointestinal involvement: a single-center experience

BACKGROUND/AIMS: The gastrointestinal (GI) tract often becomes involved in patients with systemic amyloidosis. As few GI amyloidosis data have been reported, we describe the clinical features and outcomes of patients with pathologically proven GI amyloidosis. METHODS: We identified 155 patients diagnosed with systemic amyloidosis between April 1995 and April 2013. Twenty-four patients (15.5%) were diagnosed with GI amyloidosis using associated symptoms, and the diagnoses were confirmed by direct biopsy. RESULTS: Among the 24 patients, 20 (83.3%) had amyloidosis light chain (AL), three (12.5%) had amyloid A, and one (4.2%) had transthyretin-related type amyloidosis. Their median age was 57 years (range, 37 to 72), and 10 patients were female (41.7%). The most common symptoms of GI amyloidosis were diarrhea (11 patients, 45.8%), followed by anorexia (nine patients, 37.5%), weight loss, and nausea and/or vomiting (seven patients, 29.2%). The histologically confirmed GI tract site in AL amyloidosis was the stomach in 11 patients (55.0%), the colon in nine (45.0%), the rectum in seven (35.0%), and the small bowel in one (5.0%). Patients with GI involvement had a greater frequency of organ involvement (p = 0.014). Median overall survival (OS) in patients with GI involvement was shorter (7.95 months; range, 0.3 to 40.54) than in those without GI involvement (15.84 months; range, 0.0 to 114.53; p = 0.069) in a univariate analysis. A multivariate analysis of prognostic factors for AL amyloidosis revealed that GI involvement was not a significant predictor of OS (p = 0.447). CONCLUSIONS: The prognosis of patients with AL amyloidosis and GI involvement was poorer than those without GI involvement, and they presented with more organ involvement and more advanced disease than those without organ involvement.

Amiloidose familiar por transtirretina TTR Val30Met e os primórdios do Centro de Estudos de Paramiloidose Antonio Rodrigues de Mello / Principles of the Familial transthyretin amyloidosis TTR Val30Met and the beginning of the Paramyloidosis Center of Antonio Rodrigues de Mello

Objetivos: considerar as etapas de desenvolvimento do conhecimento sobre a Polineuropatia amiloidótica familiar de Corino Andrade, atualmente conhecida como Amiloidose familiar por transtirretina (TTR) TTR Val30Met - AFTTTRVal30Met; registrar os primórdios e os princípios fundamentais do Centro de Estudos de Paramiloidose Antonio Rodrigues de Mello (CEPARM) de atendimento aos sofredores de doença de herança autossômica dominante sistêmica e com polineuropatia de predomínio sensitivo-motora-autonômica; rever aspectos atuais sobre a doença, etiológicos, epidemiológicos, clínicos, diagnósticos e terapêuticos. Método: Revisão narrativa sobre a AFTTTRVal30Met baseada em: documentos da época da fundação do CEPARM e de seis casos iniciais (além de outros 23 arrolados pelo Centro Português); artigos recentes. Resultados: Três momentos básicos são registrados no desenvolvimento do conhecimento sobre os doentes: 1-o inicial, clínico-patológico (1939-52); 2-da abordagem multiprofissional (1952-80); 3-de melhor conhecimento da sua fisiopatogenia e tentativa de debelá-la ou abrandá-la, aí mencionadas as revelações genômicas e o papel da TTR mutante (TTRm) (1980-91); 4-a partir do transplante hepático e evolução do conhecimento sobre a TTRm (1991-). A criação do CEPARM surgiu na confluência dos momentos dois e três: necessidade de contemplar o atendimento integral aos sofredores da doença ultrapassando a etapa diagnóstica, e início da definição da pré-albumina anômala (TTRm). Conclusão: a abordagem multidisciplinar continua a ser a meta de atendimento aos pacientes com PAF, além das iniciativas ao aprimoramento terapêutico, diagnóstico e profilático da doença, dependentes da aliança com áreas de pesquisa das ciências biológicas.

Objective: to consider the development stages of the knowledge about the Familial amyloid neuropathy of Corino Andrade, currently known as Familial transthyretin (TTR) amyloidosis TTR Val30Met - FTATTR Val30Met; to register the beginnings and the basic principles of the Center of Studies of Paramyloidosis Antonio Rodrigues de Mello (CEPARM) of the disease sufferers consultations: systemic disease, autosomal dominant inheritance, sensorial-motor and autonomic polyneuropathy; to review the current state of knowledge on the illness, etiologic, clinical, epidemiologic, diagnostic and therapeutic. Method: Narrative review about FTAVal30Met based on: documents at the time of CEPARM foundation and the initial cases (beyond 24 others enrolled by the Portuguese Center); recent articles. Results: in the development of the knowledge on the mentioned patients: 1-initial, medical-pathological one (1939-52); 2-of multiprofessional approach (1952-80); 3 of better knowledge of its physiopathogeny and attempt to reduce or eradicate it, the genomics revelations and the paper of the mutant TTR (TTRm) (1980-91); 4-from the first liver transplant and the increasing knowledge about the TTRm (1991-). The creation of the CEPARM appeared in the confluence of moments two and three: necessity to contemplate the integrated management of the patients exceeding the diagnostic stage, and the beginning of the definition of the anomalous pre-albumin (TTRm). Conclusion: the patients' multidisciplinary approach continues to be the main goal of their management, besides the initiatives to improve therapeutic, diagnostic and prophylactics goals, based on the alliance between basic and clinical sciences.

Diagnóstico de polineuropatía amiloidótica familiar tipo I en la Argentina / Diagnosis of familial amyloid polyneuropathy type I in Argentina

La polineuropatía amiloidótica familiar (PAF) es un tipo de amiloidosis hereditaria. Constituye un desorden autosómico dominante caracterizado por el depósito sistémico de material amiloide en tejidos especialmente en nervios periféricos. El principal componente del amiloide es una variante mutada de la transtiretina (TTR), proteína transportadora de tiroxina y retinol. Han sido descriptas numerosas mutaciones en el gen TTR que causan alteración de la secuencia primaria de la proteína. La PAF portuguesa o PAF Tipo I se origina por la variante TTR Val30Met en la cual una valina en posición 30 es reemplazada por una metionina. Es fundamental la identificación temprana de portadores de la mutación porque una vez declarada la enfermedad el único tratamiento efectivo es el trasplante hepático, órgano de síntesis de la TTR. La PAF Tipo I ha sido muy estudiada en la Argentina debido al hallazgo de un área endémica donde habitan familias descendientes de inmigrantes portugueses. El presente trabajo ha sido enfocado a resolver la necesidad diagnóstica de la comunidad, ya que la ausencia de una metodología apropiada en nuestro país ha impedido, hasta ahora, que individuos con antecedentes familiares de PAF puedan tener un diagnóstico precoz y acceder al trasplante hepático temprano. En consecuencia, nuestro objetivo fue optimizar una metodología para detectar la mutación Val30Met adaptando técnicas previamente descriptas. La fiabilidad, sencillez y rapidez en la obtención de los resultados, así como el requerimiento de pequeño volumen de muestra, hacen que la técnica desarrollada en este trabajo sea una herramienta apropiada para procedimientos de screening, permitiendo contar con un marcador preclínico de la enfermedad.

Familial amyloid polyneuro- pathy (FAP) is an autosomal dominant inherited disease, characterized by systemic deposition of amyloid fibrils in various tissues, especially in peripheral nerves, being a variant of transthyretin (TTR) the principal component of amyloid fibrils. TTR is a normal plasma protein (previously called prealbumin) that functions as a transport protein binding tiroxine and retinol. Among many mutations that have been found in the TTR gene, the variant with a single amino acid substitution of methionine for valine at position 30 (TTR Val30Met) is the responsible of the Portuguese-type Familial Amyloidotic Polyneuropathy (FAP Type I). Interest in this pathology has arisen in Argentina because of the finding of an endemic area where a group of Portuguese immigrant families is localized. Since liver transplantation is a widely accepted treatment because it results in the disappearance of variant transthyretin from plasma, an early detection of the altered gene is essential. Thus, the objective of the present work was to optimize a methodology to detect the Val30Met mutation introducing modifications into techniques that were previously developed. The simple method here described is useful to confirm the diagnosis of the potential disease and, therefore, make it possible for patients to gain access to early liver transplantation.

Polineuropatía amiloidótica familiar tipo I / Familial amyloidotic polyneuropathy type I

Familial amyloidotic polyneuropathy type I is an autosomal dominant inherited disorder characterized by progressive peripheral and autonomic neuropathy, associated with neural and systemic amyloid deposits. The abnormality usually lies in the transthyretin (TTR) gene. We report a 25 years old man with 18 months history of dysesthesias and pain in the toes, abnormal micturition and sexual dysfunction. Neurophysiologically studies disclosed a sensory-motor axonal polyneuropathy. Autonomic tests showed sympathetic and parasympathetic involvement. An electron micrograph of sural nerve revealed amyloid fibrils in the endoneurium. His mother died after a clinical history suggestive, in retrospect, of familial amyloidotic polyneuropathy type I. The clinical and genetic analysis of this cause of polyneuropathy are discussed.