Charcot-Marie-Tooth disease: from historical landmarks in Brazil to current care perspectives / Doença de Charcot-Marie-Tooth: dos marcos históricos no Brasil até as perspectivas atuais de cuidado

Abstract Hereditary motor and sensory neuropathy, also known as Charcot-Marie-Tooth disease (CMT), traditionally refers to a group of genetic disorders in which neuropathy is the main or sole feature. Its prevalence varies according to different populations studied, with an estimate between 1:2,500 to 1:10,000. Since the identification of PMP22 gene duplication on chromosome 17 by Vance et al., in 1989, more than 100 genes have been related to this group of disorders, and we have seen advances in the care of patients, with identification of associated conditions and better supportive treatments, including clinical and surgical interventions. Also, with discoveries in the field of genetics, including RNA interference and gene editing techniques, new treatment perspectives begin to emerge. In the present work, we report the most import landmarks regarding CMT research in Brazil and provide a comprehensive review on topics such as frequency of different genes associated with CMT in our population, prevalence of pain, impact on pregnancy, respiratory features, and development of new therapies.

Resumo A neuropatia sensitivo-motora hereditária, também conhecida como doença de Charcot-Marie-Tooth (CMT), tradicionalmente se refere a um grupo de doenças genéticas em que a neuropatia é a principal ou única manifestação. Sua prevalência varia de acordo com as diferentes populações estudadas, com estimativa entre 1:2.500 a 1:10.000. Desde a identificação da duplicação do gene PMP22 no cromossomo 17, por Vance et al., em 1989, mais de 100 genes foram relacionados a esse grupo de doenças e temos visto avanços no atendimento aos pacientes, com identificação de condições associadas e melhores tratamentos de suporte, incluindo intervenções clínicas e cirúrgicas. Além disso, com as descobertas no campo da genética, incluindo técnicas de interferência de RNA e de edição genética, novas perspectivas de tratamento começaram a surgir. No presente trabalho, relatamos os marcos mais importantes sobre a pesquisa de CMT no Brasil e fornecemos uma revisão abrangente sobre tópicos como frequência de diferentes genes associados à CMT em nossa população, prevalência de dor, impacto na gravidez, alterações respiratórias e desenvolvimento de novas terapias.

Hereditary neuropathy with liability to pressure palsies / 中华神经科杂志

Hereditary neuropathy with liability to pressure palsies (HNPP) is an autosomal dominant hereditary sensory and motor neuropathy characterized by recurrent numbness and limb weakness. In clinical practice, some patients may present with mild or atypical clinical symptoms, which tends to result in missed diagnosis or misdiagnosis of HNPP. This article summarizes the pathogenesis, epidemiology, clinical manifestations, auxiliary examination, diagnosis and differential diagnosis, management, and prognosis of HNPP.

Analysis of clinical and electrophysiological features in patients with hereditary neuropathy with liability to pressure palsy diagnosed by gene analysis / 中华神经科杂志

Objective To study the clinical and electrophysiological features of the patients with hereditary neuropathy with liability to pressure palsy ( HNPP) diagnosed by gene analysis.Methods Seven patients from two HNPP families were assessed on medical history, physical examination, electrophysiology findings and gene analysis.Results A clinical manifestation of acute, painless, recurrent peripheral nerve palsies was typical for HNPP.Median, ulnar and peroneal nerves were usually affected.Electrophysiology study revealed that prolonged distal motor latency and slowing nerve conduction velocity were prominent.Gene studies exhibited a deletion of the peripheral myelination protein 22 gene in all the seven patients.Conclusions HNPP usually affects areas where nerves are subject to entrapment, and many episodes are preceded by minor compression on the affected nerve.As a reliable screening tool in detecting HNPP, the electrophysiological study shows that segmental demyelination is most commonly seen at common nerve entrapment sites.

Charcot Marie Tooth disease (CMT4A) due to GDAP1 mutation: report of a colombian family / Enfermedad de Charcot Marie Tooth (CMT4A) por mutacion en el gen GDAP1: reporte de una familia colombiana

Background: Mutations of GDAP1 gene cause autosomal dominant and autosomal recessive Charcot-Marie-Tooth disease and more than 40 different mutations have been reported. The recessive Q163X mutation has been described in patients of Spanish ancestry, and a founder mutation in South American patients, originating in Spain has been demonstrated. Objective: We describe physical and histological features, and the molecular impact of mutation Q163X in a Colombian family. Methods: We report two female patients, daughters of consanguineous parents, with onset of symptoms within the first two years of life, developing severe functional impairment, without evidence of dysmorphic features, hoarseness or diaphragmatic paralysis. Electrophysiology tests showed a sensory and motor neuropathy with axonal pattern. Sequencing of GDAP1 gene was requested and the study identified a homozygous point mutation (c.487 C>T) in exon 4, resulting in a premature stop codon (p.Q163X). This result confirms the diagnosis of Charcot-Marie-Tooth disease, type 4A. Results: The patients were referred to Physical Medicine and Rehabilitation service, in order to be evaluated for ambulation assistance. They have been followed by Pulmonology service, for pulmonary function assessment and diaphragmatic paralysis evaluation. Genetic counseling was offered. The study of the genealogy of the patient, phenotypic features, and electrophysiological findings must be included as valuable tools in the clinical approach of the patient with Charcot-Marie-Tooth disease, in order to define a causative mutation. In patients of South American origin, the presence of GDAP1 gene mutations should be considered, especially the Q163X mutation, as the cause of CMT4A disease.

Antecedentes: Las mutaciones del gen GDAP1 son causantes de la enfermedad de Charcot Marie Tooth tanto autosómica dominante como recesiva, y se han reportado más de 40 mutaciones distintas. La mutación recesiva Q163X ha sido descrita en pacientes de ascendencia española y se ha demostrado una mutación fundadora originaria de España en pacientes de origen suramericano. Describimos las características físicas e histológicas y el impacto molecular de la mutación Q163X en una familia colombiana. Objetivo: Se describe el impacto de la mutación Q163X en las características físicas, histológicas y moleculares en una familia colombiana. Métodos: Se describe dos pacientes de sexo femenino, hijas de padres consanguíneos, quienes presentaron inicio de síntomas en los dos primeros años de vida, mostrando deterioro funcional severo, sin evidencia de dismorfía, disfonía o parálisis diafragmática. Los estudios de electrofisiología mostraron una neuropatía sensitiva y motora con patrón axonal. Se solicitó la secuenciación del gen GDAP1, y el estudio identificó una mutación homocigota puntual (c. 487 C>T) en el exón 4, causando un codón de parada prematuro (p. Q163X). Este resultado confirma el diagnóstico de Enfermedad de Charcot Marie Tooth, tipo 4A (recesiva, tipo axonal). Resultados: Las pacientes fueron remitidas al servicio de Fisiatría para evaluación de métodos de asistencia para deambulación. Ellas reciben seguimiento por el servicio de Neumología, quienes vigilan la función pulmonar y el desarrollo de parálisis diafragmática. Se brindó asesoramiento genético. La genealogía del paciente, las características fenotípicas y los hallazgos en los estudios electrofisiológicos son herramientas valiosas en el enfoque clínico del paciente con CMT, de forma que se pueda plantear una posible mutación causal. Se debe considerar la presencia de mutaciones en el gen GDAP1 en pacientes de origen suramericano, en especial la mutación Q163X, como causa de CMT4A.

Rapid diagnosis of hereditary neuropathy with liability to pressure palsies by multiplex ligation-dependent probe amplification / 中华神经科杂志

Objective To introduce the application of multiplex ligation-dependent probe amplification (MLPA) assays in the diagnosis of patients with hereditary neuropathy with liability to pressure palsies (HNPP).Methods Copy numbers of the exons in peripheral myelin prolein 22 (PMP22) gene,tektin 3 (TEKT3) gene and cytochrome c oxidase assembly protein 10 (COX10) gene were analyzed by MLPA in 8 patients diagnosed with HNPP clinically and 5 normal controls.Results Among the 8 patients,7 patients were identified to have deletion mutations according to their reduced peak area of PMP22 gene,TEKT3 gene and COX10 gene compared with that of normal controls.One patient with normal peak area of PMP22 gene,TEKT3 gene and COX10 gene showed no deletion of these genes.Conclusions MLPA assays can detect the copy numbers of genes in HNPP region through semi-quantitative analysis in a rapid,accurate way,which may be utilized widely in the genetic diagnosis among HNPP patients.

Complicações osteoarticulares da analgesia congênita / Osteoarticular complications of congenital analgesia

Os autores apresentam dois irmãos com diagnóstico de analgesia congênita, com suas características clínicas e evolução. Essa doença é rara, apresenta alta morbidade e gera complicações osteoarticulares de difícil solução. O objetivo dos autores foi ressaltar a importância do diagnóstico tanto para o tratamento de suas afecções secundárias, quanto para seu aspecto jurídico.

The authors present two brothers with congenital pain insensitivity, with their clinical characteristics and evolution. This disease is rare, has high morbidity and originates complex osteoarticular complications. The aim of the authors was to emphasize the value of the diagnosis for a better treatment and to avoid legal problems to the parents.