Congenital myasthenic syndrome in a cohort of patients with 'double' seronegative myasthenia gravis / Síndrome miastênica congênita em uma série de pacientes com miastenia gravis duplo soronegativa

ABSTRACT Background: Congenital myasthenic syndromes (CMS) have some phenotypic overlap with seronegative myasthenia gravis (SNMG). Objective: The aim of this single center study was to assess the minimum occurrence of CMS misdiagnosed as double SNMG in a Brazilian cohort. Methods: The genetic analysis of the most common mutations in CHRNE, RAPSN, and DOK7 genes was used as the main screening tool. Results: We performed genetic analysis in 22 patients with a previous diagnosis of 'double' SNMG. In this study, one CMS patient was confirmed due to the presence of compound heterozygous variants in the CHRNE gene (c.130insG/p.Cys210Phe). Conclusions: This study confirmed that CMS due to CHNRE mutations can be mistaken for SNMG. In addition, our study estimated the prevalence of misdiagnosed CMS to be 4.5% in 'double' SNMG patients of our center. Based on our findings, genetic screening could be helpful in the diagnostic workup of patients with 'double' SNMG in whom differential diagnosis is recommended.

RESUMO Antecedentes: As síndromes miastênicas congênitas (SMC) podem ter sobreposição fenotípica com a miastenia gravis soronegativa (MG-SN). Objetivo: Estabelecer a prevalência mínima de SMC diagnosticada inicialmente como MG duplo soronegativa em uma série de casos brasileiros. Métodos: A análise genética das mutações mais comuns nos genes CHRNE, RAPSN e DOK7 foi usada como o principal exame de triagem. Resultados: Vinte e dois pacientes com diagnóstico prévio de MG-SN foram geneticamente analisados, sendo que uma paciente foi confirmada com SMC devido a presença de variante em heterozigose composta no gene CHRNE (c.130insG/p.Cys210Phe). Conclusões: O presente estudo confirma que SMC devido mutação no gene CHNRE pode ser inicialmente diagnosticada como MG-SN. O estudo estimou como 4,5% a prevalência de diagnóstico de SMC entre nossos pacientes préviamente diagnosticados como MG-SN. Com base nesse estudo, a análise genética pode ser recomendada para investigação do diagnóstico diferencial em pacientes com MG-SN.

Centronuclear myopathy: clinical characteristics and MRI image features of oral and maxillofacial region / 中华口腔医学杂志

Objective@#To provide biomechnical basis for orthodontics of centronuclear myopathy (CNM) patients, we studied the oral and maxillofacial clinical features and MRI image manifestations to explore application of MRI to objective evaluation the affected facial muscles.@*Methods@#The study consisted of 8 patients who were diagnosed as CNM (CNM group) and 20 healthy volunteers (control group). Their medical information were gathered and then we examined the ptosis situation and the facial index calculation of them. To measure the maximal hight of palate and the width of palate, patients and volunteers were made impressions. We also checked their maximum bite force with occlusion pressure tester. And they took lateral cephalometric radiographs to measure mandibular plane-Frankfort horizontal plane angle (MP-FH). At last, they were taken oral and maxillofacial region MRI to observe the affected situation of masseter muscle, medial pterygoid muscle and lateral pterygoid muscle.@*Results@#Six patients were ptosis; 6 patients had inverse V-shaped mouth; 3 patients were difficulty in swallowing; 4 patients were anterior open bites; 4 patients were mouth breathing; 7 patients liked to eat soft foods. Morphological facial index ([91.3±0.5]%), MP-FH (34.9°±2.0°) of CNM group were greater than the control group, male maximal hight of palate ([19.0±0.2] mm), female maximal hight of palate ([18.0±0.6] mm) of CNM group were greater than the control group (P<0.05). Male width of palate ([34.5±0.8] mm), female width of palate ([33.4±1.0] mm), male maximum bite force ([464.3±78.2] N), female maximum bite force ([320.7±13.8] N), maximal opening of mouth ([3.4±0.3] cm) of CNM group were less than the control group (P<0.05). And these had significant difference compared with the control group (P<0.05). In MRI examination, there were 7 patients' masseter muscles, 4 patients' medial pterygoid muscles and 6 patients' lateral pterygoid muscles to atrophy asymmetrically. These three pieces of muscular fatty infiltration were inordinately, focused on Grade 0 to 4 and the both sides were similar.@*Conclusions@#CNM patients with long and thin face, high palatine arches and low bite force together were the biomechanical basis of the maxillofacial deformities. MRI can clearly show the affected masseter muscle, medial pterygoid muscle, lateral pterygoid muscle, and can serve as an objective examination method for the evaluation of facial muscles. It can be worth of clinical popularization and application.

Clinical phenotypes and pathological features in myopathies with tubular aggregates / 中华神经科杂志

Objective To summarize clinical phenotypes and pathological characteristics in myopathies with tubular aggregates (TAs).Methods We reviewed 5 697 patients who performed muscle biopsies in our department between January 2001 and July 2015.We collected the cases with TAs and made classification based on their clinical diagnoses and pathological changes.Results Fifty-seven patients (1.00％) showed TAs in muscle specimens,including 50 (87.72％) males and 7 (12.28％) females.According to clinical,neurophysiological,pathological and genetic analysis,the diagnoses included 23 (40.35％) cases of periodic paralysis,7 (12.28％) cases of chronic alcohol intoxication,6 (10.53％) cases of congenital myasthenic syndrome,5 (8.77％) cases of exercise-induced cramps,3 (5.26％) cases of necrotizing myopathy,1 (1.75％) case of stromal interaction molecule 1-associated myopathy,limbgirdle muscular dystrophy 2E,myotonic dystrophy,myotonia congenita,paramyotonia congenitia,hypothyroid myopathy respectively.Other cases of unknown cause included unclassified distal myopathy,external ophthalmoplegia,white matter lesions,mental retardation,stroke,early onset weakness,pulmonary arterial hypertension.Besides TAs,pathological changes also included necrosis of muscle fibers (3 cases,5.26％),neurogenic changes (3 cases,5.26％) and muscular dystrophic changes (1 case,1.75％).Conclusions Our results indicated that TAs are usually found in males and could present in many types of hereditary or acquired neuromuscular disease as independent or accompanying changes.Periodic paralysis,chronic alcohol intoxication and congenital myasthenic syndrome are 3 major diseases causing myopathies with TAs.