PURPOSE: This study was designed to investigate the characteristics of Korean patients with calpainopathy. MATERIALS AND METHODS: Thirteen patients from ten unrelated families were diagnosed with calpainopathy via direct or targeted sequencing of the CAPN3 gene. Clinical, mutational, and pathological spectra were then analyzed. RESULTS: Nine different mutations, including four novel mutations (NM_000070: c.1524+1G>T, c.1789_1790inA, c.2184+1G>T, and c.2384C>T) were identified. The median age at symptom onset was 22 (interquartile range: 15-28). Common clinical findings were joint contracture in nine patients, winged scapula in four, and lordosis in one. However, we also found highly variable clinical features including early onset joint contractures, asymptomatic hyperCKemia, and heterogeneous clinical severity in three members of the same family. Four of nine muscle specimens revealed lobulated fibers, but three showed normal skeletal muscle histology. CONCLUSION: We identified four novel CAPN3 mutations and demonstrated clinical and pathological heterogeneity in Korean patients with calpainopathy.
Adolescent ; Adult ; Amino Acid Sequence ; Asian Continental Ancestry Group/*genetics ; Calpain/*genetics ; Female ; Genetic Testing ; Humans ; Male ; Molecular Sequence Data ; Muscle Proteins/*genetics ; Muscle, Skeletal/pathology ; Muscular Dystrophies, Limb-Girdle/ethnology/*genetics/*pathology ; *Mutation ; Republic of Korea

BACKGROUNDDysferlinopathy is caused by mutations in the dysferlin (DYSF) gene. Here, we described the genetic features of a large cohort of Chinese patients with this disease.

METHODSEighty-nine index patients were included in the study. DYSF gene analysis was performed by Sanger sequencing in 41 patients and targeted next generation sequencing (NGS) in 48 patients. Multiplex ligation-dependent probe amplification (MLPA) was performed to detect exon duplication/deletion in patients with only one pathogenic mutation.

RESULTSAmong the 89 index patients, 79 patients were demonstrated to carry two disease-causing (73 cases) or possibly disease-causing mutations (6 cases), including 26 patients with homozygous mutations. We identified 105 different mutations, including 59 novel ones. Notably, in 13 patients in whom only one pathogenic mutation was initially found by Sanger sequencing or NGS, 3 were further identified to carry exon deletions by MLPA. The mutations identified in this study appeared to cluster in the N-terminal region. Mutation types included missense mutations (30.06%), nonsense mutations (17.18%), frameshift mutations (30.67%), in-frame deletions (2.45%), intronic mutations (17.79%), and exonic rearrangement (1.84%). No genotype-phenotype correlation was identified.

CONCLUSIONSDYSF mutations in Chinese patients clustered in the N-terminal region of the gene. Exonic rearrangements were found in 23% of patients with only one pathogenic mutation identified by Sanger sequencing or NGS. The novel mutations found in this study greatly expanded the mutational spectrum of dysferlinopathy.

Adolescent ; Adult ; Asian Continental Ancestry Group ; Child ; China ; Codon, Nonsense ; genetics ; Dysferlin ; Exons ; genetics ; Female ; Frameshift Mutation ; genetics ; Gene Frequency ; genetics ; Genotype ; High-Throughput Nucleotide Sequencing ; Humans ; Male ; Membrane Proteins ; genetics ; Middle Aged ; Muscle Proteins ; genetics ; Muscular Dystrophies, Limb-Girdle ; genetics ; Mutation ; genetics ; Mutation, Missense ; genetics ; Phenotype ; Young Adult

OBJECTIVETo elucidate the usefulness of next generation sequencing for diagnosis of inherited myopathy, and to analyze the relevance between clinical phenotype and genotype in inherited myopathy.

METHODRelated genes were selected for SureSelect target enrichment system kit (Panel Version 1 and Panel Version 2). A total of 134 patients who were diagnosed as inherited myopathy clinically underwent next generation sequencing in Department of Pediatrics, Peking University First Hospital from January 2013 to June 2014. Clinical information and gene detection result of the patients were collected and analyzed.

RESULTSeventy-seven of 134 patients (89 males and 45 females, visiting ages from 6-month-old to 26-year-old, average visiting age was 6 years and 1 month) underwent next generation sequencing by Panel Version 1 in 2013, and 57 patients underwent next generation sequencing by Panel Version 2 in 2014. The gene detection revealed that 74 patients had pathogenic gene mutations, and the positive rate of genetic diagnosis was 55.22%. One patient was diagnosed as metabolic myopathy. Five patients were diagnosed as congenital myopathy; 68 were diagnosed as muscular dystrophy, including 22 with congenital muscular dystrophy 1A (MDC1A), 11 with Ullrich congenital muscular dystrophy (UCMD), 6 with Bethlem myopathy (BM), 12 with Duchenne muscular dystrophy (DMD) caused by point mutations in DMD gene, 5 with LMNA-related congenital muscular dystrophy (L-CMD), 1 with Emery-Dreifuss muscular dystrophy (EDMD), 7 with alpha-dystroglycanopathy (α-DG) patients, and 4 with limb-girdle muscular dystrophy (LGMD) patients.

CONCLUSIONNext generation sequencing plays an important role in diagnosis of inherited myopathy. Clinical and biological information analysis was essential for screening pathogenic gene of inherited myopathy.

Adolescent ; Child ; Child, Preschool ; Contracture ; DNA Mutational Analysis ; Female ; Genetic Diseases, Inborn ; diagnosis ; genetics ; Genetic Testing ; Genotype ; High-Throughput Nucleotide Sequencing ; Humans ; Infant ; Male ; Molecular Diagnostic Techniques ; Muscular Diseases ; diagnosis ; genetics ; Muscular Dystrophies ; congenital ; Muscular Dystrophies, Limb-Girdle ; Muscular Dystrophy, Duchenne ; Muscular Dystrophy, Emery-Dreifuss ; Mutation ; Phenotype ; Sclerosis ; Walker-Warburg Syndrome ; Young Adult

OBJECTIVETo investigate TCAP gene mutation and clinical features of a Chinese patient with limb-girdle muscular dystrophy type 2G(LGMD 2G).

METHODSClinical data of the patient was analyzed. Exons of the TCAP gene were amplified and sequenced.

RESULTSThe patient has presented clinically as LGMD and pathologically as vacuolar myopathy. Genetic analysis has identified compound heterozygous mutations of exons 1 and 2 of the TCAP gene(c.100delC, c.166insG).

CONCLUSIONLGMD is a group of neuromuscular disorders with substantial phenotypic heterogeneity. Genetic diagnosis has become indispensable for accurate diagnosis for patients suspected to have the disease.

Adult ; Base Sequence ; Connectin ; genetics ; Exons ; Female ; Humans ; Molecular Sequence Data ; Muscular Dystrophies, Limb-Girdle ; genetics ; Young Adult

Dysferlinopathy is caused by mutations in the DYSF gene. To characterize the clinical spectrum, we investigated the characteristics of 31 Korean dysferlinopathy patients confirmed by immunohistochemistry. The mean age of symptom onset was 22.23 +/- 7.34 yr. The serum creatine kinase (CK) was highly increased (4- to 101-fold above normal). The pathological findings of muscle specimens showed nonspecific dystrophic features and frequent inflammatory cell infiltration. Muscle imaging studies showed fatty atrophic changes dominantly in the posterolateral muscles of the lower limb. The patients with dysferlinopathy were classified by initial muscle weakness: fifteen patients with Miyoshi myopathy phenotype (MM), thirteen patients with limb girdle muscular dystrophy 2B phenotype (LGMD2B), two patients with proximodistal phenotype, and one asymptomatic patient. There were no differences between LGMD2B and MM groups in terms of onset age, serum CK levels and pathological findings. Dysferlinopathy patients usually have young adult onset and high serum CK levels. However, heterogeneity of clinical presentations and pathologic findings upon routine staining makes it difficult to diagnose dysferlinopathy. These limitations make immunohistochemistry currently the most important method for the diagnosis of dysferlinopathy.
Adolescent ; Adult ; Age of Onset ; Creatine Kinase/blood ; Distal Myopathies/pathology ; Female ; Humans ; Immunohistochemistry ; Male ; Membrane Proteins/genetics ; Middle Aged ; Muscle Proteins/genetics ; Muscular Atrophy/pathology ; Muscular Dystrophies, Limb-Girdle/*diagnosis/genetics/pathology ; Mutation ; Phenotype ; Republic of Korea ; Tomography, X-Ray Computed ; Young Adult

This study was performed in order to characterize the types of the infiltrating cells, and the expression profiles of major histocompatibility complex (MHC) class I and membrane attack complex (MAC) in patients with inflammatory myopathies and dysferlinopathy. Immunohistochemical stains were performed using monoclonal antibodies against several inflammatory cell types, MHC class I, and MAC in muscles from inflammatory myopathies and dysferlinopathy. There was significant difference in the types of infiltrating cells between polymyositis (PM), dermatomyositis (DM), and dysferlinopathy, including significantly high CD4+/CD8+ T cell ratio and B/T cell ratio in DM. In dysferlinopathy, CD4+ T cells were the most abundant and the proportions of infiltrating cell types were similar to those of DM. MHC class I was expressed in muscle fibers of PM and DM regardless of the presence of inflammatory infiltrates. MAC was expressed in necrotic fibers and vessels of PM and DM. One patient with early stage DM had a MAC deposits on endomysial capillaries. In dysferlinopathy, MAC deposit was also observed on the sarcolemma of nonnecrotic fibers. The analysis of inflammatory cells, MHC class I expressions and MAC deposits may help to differentiate dysferlinopathy from idiopathic inflammatory myopathy.
Adult ; Aged ; *Dermatomyositis/immunology/pathology ; Female ; Genes, MHC Class I ; Humans ; Male ; *Membrane Proteins/genetics/immunology ; Middle Aged ; Muscle Fibers, Skeletal/cytology/immunology/pathology ; *Muscle Proteins/genetics/immunology ; *Muscular Dystrophies, Limb-Girdle/immunology/pathology ; *Myositis/immunology/pathology ; *Polymyositis/immunology/pathology ; T-Lymphocytes/cytology/immunology/pathology ; Young Adult

BACKGROUNDMutations of the LMNA gene encoding lamin A and C are associated with dilated cardiomyopathy (DCM), conduction system defects and skeletal muscle dystrophy. Here we report a family with a mutation of the LMNA gene to identify the relationship between genotype and phenotype.

METHODSAll 30 members of the family underwent clinical and genetic evaluation. A mutation analysis of the LMNA gene was performed. All of the 12 exons of LMNA gene were extended with polymerase chain reaction (PCR) and the PCR products were screened for gene mutation by direct sequencing.

RESULTSTen members of the family had limb-girdle muscular dystrophy (LGMD) and 6 are still alive. Two patients suffered from DCM. Cardiac arrhythmias included atrioventricular block and atrial fibrillation; sudden death occurred in 2 patients. The pattern of inheritance was autosomal dominant. Mutation c.73C > G (R25G) in exon 1 encoding the globular domains was confirmed in all of the affected members, resulting in the conversion of arginine (Arg) to glycine (Gly).

CONCLUSIONSThe mutation R25G in exon 1 of LMNA gene we reported here in a Chinese family had a phenotype of malignant arrhythmia and mild LGMD, suggesting that patients with familial DCM, conduction system defects and skeletal muscle dystrophy should be screened by genetic testing for the LMNA gene.

Adult ; Cardiomyopathy, Dilated ; genetics ; Exons ; Humans ; Lamin Type A ; genetics ; Muscular Dystrophies, Limb-Girdle ; genetics ; Mutation

The limb-girdle muscular dystrophy type 2A (LGMD2A) is a recessively inherited disease caused by a mutation of the calpain 3 gene (CAPN3), and is considered one of the most prevalent subtypes of limb-girdle muscular dystrophy (LGMD). In this study, we aimed to identify CAPN3 mutations and to characterize the phenotype of Korean patients with LGMD2A. Among 35 patients with LGMD, four patients, who showed calpain 3 deficiency on western blot analysis, were analyzed in this study. Total RNA extracted from frozen muscle tissue was amplified by reverse transcriptase polymerase chain reaction (RT-PCR) using six primer pairs covering all coding sequences of CAPN3, and direct sequencing was performed. Clinical and pathological features of the patients were also reviewed. We found four different mutations in five alleles from three patients. Of the pathogenic mutations identified, two were novel (c.2125T>C and c.2355-2357delTTC), and the others had been reported elsewhere (c.440G>C, c.1076C>T). All patients showed a high CK level with predominant proximal leg weakness, and the onset was in their childhood except for one patient. Among two novel CAPN3 mutations, one was a missense mutation (c.2125T>C [p.709Ser>Pro]), and the other was a small in-frame deletion causing omission of a single amino acid (c.2355-2357delTTC [p.786delPhe]). The clinical features of our patients were generally compatible with the characteristics of LGMD2A patients described in the previous studies.
Adolescent ; Adult ; Amino Acid Sequence ; Base Sequence ; Calpain/*genetics ; DNA Primers/chemistry ; Female ; Humans ; Korea ; Male ; Middle Aged ; Molecular Sequence Data ; Muscle Proteins/*genetics ; Muscular Dystrophies, Limb-Girdle/*genetics ; *Mutation ; Sequence Homology, Amino Acid