Progression of GNE Myopathy Based on the Patient-Reported Outcome

BACKGROUND AND PURPOSE: GNE myopathy is a rare progressive myopathy caused by biallelic mutations in the GNE gene, and frequently accompanied by rimmed vacuoles in muscle pathology. The initial symptom of foot drop or hip-girdle weakness eventually spreads to all limbs over a period of decades. Recent advances in pathophysiologic research have facilitated therapeutic trials aimed at resolving the core biochemical defect. However, there remains unsettled heterogeneity in its natural course, which confounds the analysis of therapeutic outcomes. We performed the first large-scale study of Korean patients with GNE myopathy. METHODS: We gathered the genetic and clinical profiles of 44 Korean patients with genetically confirmed GNE myopathy. The clinical progression was estimated retrospectively based on a patient-reported questionnaire on the status of the functional joint sets and daily activities. RESULTS: The wrist and neck were the last joints to lose antigravity functionality irrespective of whether the weakness started from the ankle or hip. Two-thirds of the patients could walk either independently or with an aid. The order of losing daily activities could be sorted from standing to eating. Patients with limb-girdle phenotype showed an earlier age at onset than those with foot-drop onset. Patients with biallelic kinase domain mutations tended to progress more rapidly than those with epimerase and kinase domain mutations. CONCLUSIONS: The reported data can guide the clinical management of GNE myopathy, as well as provide perspective to help the development of clinical trials.

Miopatias com padrão distal: descrição clínica de pacientes do Estado da Bahia / Distal myopathies: clinical description of patients from the State of Bahia

INTRODUÇÃO: As miopatias são doenças cuja etiologia decorre de alterações estruturais e/ou funcionais no músculo esquelético. As miopatias distais são doenças musculares primárias em que fraqueza e, frequentemente atrofia, tem início nas mãos, antebraços, pés e segmento distal das pernas. Apesar de terem sido divididas como um grupo restrito de doenças, outras miopatias podem se manifestar com um padrão distal, como a miopatia nemalínica e as distrofias musculares cintura-membros. Devido à escassez de trabalhos que descrevem clinicamente as miopatias distais, este trabalho visou contribuir com essa caracterização. METODOLOGIA: Os pacientes foram selecionados no ambulatório de doenças neuromusculares do Hospital Universitário Professor Edgar Santos, em seguida avaliados clinicamente, através de exame físico e também com exames complementares: eletroneuromiografia, exames laboratoriais, estudo molecular e histopatológico. RESULTADOS: Quinze pacientes com padrão distal foram analisados, sendo 40% do sexo feminino, média de idade de 29,8 anos, seis (40|%) pacientes naturais da capital, Salvador-Bahia. Quanto ao padrão de distribuição de fraqueza, sete apresentavam padrão distal, enquanto oito, padrão distal-proximal. Os pacientes foram agrupados de acordo com a idade de início dos sintomas, sendo 11 iniciados na infância e adolescência (T em homozigose), um com sarcoglicanopatia (mutação c.229C>T em homozigose) e um com miopatia nemalínica (histopatológico com presença de corpos nemalínicos). DISCUSSÃO: Os achados identificados nos pacientes com diagnósticos firmados foram compatíveis com o que é visto na literatura, como apresentação clínica e mutações identificadas previamente. Destaca-se o componente distal pronunciado da paciente com sarcoglicanopatia, considerado incomum. Além disso, a descrição da ressonância magnética realizada nos indivíduos demonstrou um padrão típico. Na maior parte dos pacientes não se chegou a um diagnóstico etiológico, a despeito da investigação realizada com os exames complementares e clínicos. CONCLUSÃO: O presente estudo caracterizou uma amostra de pacientes com miopatias distais, corroborando que essas doenças se manifestam clinicamente de forma heterogênea. A caracterização e divisão entre grupos visa tornar mais fácil a investigação, devendo ser feita com exames complementares, considerados imprescindíveis para se estabelecer o diagnóstico etiológico dessas doenças

INTRODUCTION: Myopathies are diseases which etiology results from structural and/or functional changes in skeletal muscle. Distal myopathies are a group of muscular pathologies in which weakness and atrophy begins and predominates in distal limbs, like hands and feet. Although it has been divided as a restrict group of diseases, other myopathies can manifest with that pattern of weakness, such nemaline myopathy and limb-girdle muscular dystrophies. Due to the scarcity of studies that described clinically the distal myopathies, this study focuses on clinical characterization of myopathies with distal pattern of weakness. METHODOLOGY: The patients were selected in the outpatient clinic for neuromuscular diseases at Professor Edgar Santos University Hospital. Those subjects were clinically evaluated through physical examination, laboratory tests, electroneuromyography, magnetic resonance (MRI) and histopathological study. RESULTS: Fifteen patients with distal pattern were analyzed, being 40% female, mean age 29.8 years, six (40 %) patients were born in the capital, Salvador-Bahia. As for the pattern of weakness distribution, seven had an exclusive distal pattern, while eight had a distal-proximal pattern. Patients were grouped according to the age of onset of symptoms, of which 11 were initiated in childhood and adolescence ( T in homozygous in exon 53 in another and one patient were diagnosed by biopsy), one with sarcoglicanopathy (mutation c.229C> T in homozygous) and one with nemaline myopathy (histopathological with the presence of nemalinic bodies). DISCUSSION: The findings identified in patients with established diagnoses were compatible with what is seen in the literature, such as clinical presentation and previously identified mutations. We highlight the pronounced distal component of the patient with sarcoglicanopathy, considered to be uncommon. In addition, the description of MRI performed in the individuals demonstrated a typical pattern. Most of the patients were not diagnosed, despite the research done with the complementary and clinical exams. CONCLUSION: The present study characterized a sample of patients with distal myopathies, corroborating that these diseases manifest themselves clinically heterogeneously. The characterization and division between groups aims to make the investigation easier, and should be done with complementary tests, considered essential to establish the etiological diagnosis of these diseases

Clinical and pathological analysis of 11 cases of extraocular muscle paralysis was misdiagnosed as muscular disease myasthenia gravis / 重庆医学

Objective To analyse the clinical and pathological characteristics of patients with myopathies that were misdiag-nosed as myasthenia gravis because of external ophthalmoplegia ,widen the thoughts for differential diagnosis of extraocular muscle paralysis .Methods The clinical and pathological features of 11 myopathy cases with ptosis and diplopia admitted to the neurology department of the First Affiliated Hospital of Chongqing Medical University between October 2010 and May 2014 were retrospec-tively reviewed and analyzed .Results Among the 11 patients ,6 male and 5 female ,aged 16-66 years old .All had paralysis of ex-traocular muscle manifestations ,including oculopharyngeal muscular dystrophy(OPMD) in 3 cases ,oculopharyngeal distal myopa-thy in 2 cases ,chronic progressive external ophthalmoplegia(CPEO) in 6 cases .Muscle biopsy showed the characteristic pathologi-cal changes .Statistical analysis showed that the age of onset in OPMD patients was older(P0 .05) .Conclusion Certain rare myopa-thy should be considered for patients with external ophthalmoplegia seemingly myasthenia gravis .Muscle biopsy can provide clue for differential diagnosis .

Novel Mutation of the GNE Gene Presenting Atypical Mild Clinical Feature: A Korean Case Report

Glucosamine (UDP-N-acetyl)-2-epimerase/N-acetylmannosamine kinase (GNE) myopathy is caused by mutations in GNE, a key enzyme in sialic acid biosynthesis. Here, we reported a case of GNE that presented with atypical mild clinical feature and slow progression. A 48-year-old female had a complaint of left foot drop since the age of 46 years. Electromyography (EMG) and muscle biopsy from left tibialis anterior muscle were compatible with myopathy. Genetic analysis led to the identification of c.1714G>C/c.527A>T compound heterozygous mutation, which is the second most frequent mutation in Japan as far as we know. Previous research has revealed that c.1714G>C/c.527A>T compound heterozygous mutation is a mild mutation as the onset of the disease is much later than the usual age of onset of GNE myopathy and the clinical course is slowly progressive. This was the first case report in Korea of the clinicopathological characteristics of GNE myopathy with GNE (c.1714G>C/c.527A>T compound heterozygous) mutation.

Nonaka Myopathy: A case report

Nonaka myopathy (NM) or distal myopathy with rimmed vacuoles was an autosomal recessive muscle disease with preferential involvement of the tibialis anterior and sparing quadriceps muscles in young adulthood. Patients with NM usually showed slightly elevated serum creatine kinase (CK) levels and characteristic rimmed vacuoles in muscle biopsy. Recently, the UDP-N-acetylglucosamine-2-epimerase/N-ace-tylmannosamine kinase (GNE) gene was identified as the identified as the causative gene for NM. Here we reported a NM patient carrying homozygous mutations (V572L) of the GNE gene. To the best of our knowledge, this was the first report of genetically confirmed NM in Korea and NM should be included in the differential diagnosis of slowly progressive weakness of distal legs.

Distal Myopathy of Miyoshi Type: 1 Case

Miyoshi myopathy (MM) is a type of distal myopathy that is characterized by an early adult onset and a prominent involvement of the gastrocnemius muscles. Weakness usually appears between 15 and 30 years of age starting in the posterior compartment of the legs. Creatine kinase (CK) values are characteristically elevated to levels 10 to 100 fold above normal range. Here we report one patient who was diagnosed as MM. She developed a motor weakness in her early thirties. There was an early and predominant involvement of the gastrocnemius muscles. Creatine kinase activity was elevated 10 to 15 fold above normal range. Electromyography revealed fibrillations, positive sharp waves, and a myopathic pattern of motor unit potentials, particularly in the distal muscles of the lower limbs. Myopathic features without vacuoles were seen in the vastus lateralis muscle. This is the first case report of MM in Korea, which should be considered in the differential diagnosis of slowly progressive weakness of distal legs.

Distal Myopathy of Miyoshi Type: 1 Case

Miyoshi myopathy (MM) is a type of distal myopathy that is characterized by an early adult onset and a prominent involvement of the gastrocnemius muscles. Weakness usually appears between 15 and 30 years of age starting in the posterior compartment of the legs. Creatine kinase (CK) values are characteristically elevated to levels 10 to 100 fold above normal range. Here we report one patient who was diagnosed as MM. She developed a motor weakness in her early thirties. There was an early and predominant involvement of the gastrocnemius muscles. Creatine kinase activity was elevated 10 to 15 fold above normal range. Electromyography revealed fibrillations, positive sharp waves, and a myopathic pattern of motor unit potentials, particularly in the distal muscles of the lower limbs. Myopathic features without vacuoles were seen in the vastus lateralis muscle. This is the first case report of MM in Korea, which should be considered in the differential diagnosis of slowly progressive weakness of distal legs.

Miyoshi Myopathy: A case report

Miyoshi myopathy is a rare distal myopathy of early adult onset and autosomal recessive inheritance. Weakness usually appears between 15 and 30 years of age starting from the posterior compartment of the legs. Serum creatine kinase (CK) level is characteristically elevated to 10- to 100-fold above the normal range. Muscle biopsy shows myopathic changes without vacuoles consistent with muscular dystrophy. It has not been reported in Korea as yet, so far as we know. We report a 23-year-old female who had the typical manifestations of Miyoshi myopathy with the brief review of literatures.