Recent genetic and immunohistochemical analyses have shown that Miyoshi myopathy (MM) is caused by a mutation in the DYSF gene, which induces dysfunction of dysferlin. The author described one patient showing characteristic MM phenotype with deficiency of dysferlin on immunohistochemistry. Direct DNA sequencing of whole exons of DYSF gene revealed one homozygous missense mutation (G1165C) on exon 12, which let to an amino acid substitution from the glutamic acid to glutamine at the 389 of the peptide sequence in this patient. This is the first reported case of MM confirmed by immunohistochemical and genetic analyses in Korea.
Adult ; Caveolins/analysis ; Distal Myopathies/*genetics ; Humans ; Immunohistochemistry ; Male ; Membrane Proteins/chemistry/*genetics ; Muscle Proteins/chemistry/*genetics ; *Mutation ; Research Support, Non-U.S. Gov't

PURPOSE: Glucosamine (UDP-N-acetyl)-2-epimerase/N-acetylmannosamine kinase (GNE) myopathy is an autosomal recessive neuromuscular disorder characterized by early adult-onset weakness of the distal muscles of the lower limbs. The clinical spectrum of GNE myopathy varies, and it is not clear how the same GNE gene mutations can result in different phenotypes. Here, we present clinical, pathological and genetic characteristics of twenty-one Korean patients with GNE myopathy. MATERIALS AND METHODS: Twenty-one GNE myopathy patients were included in this study, conducted from 2004 to 2011. Based on medical records, patients' gender, onset age, family history, clinical history, serum creatine kinase (CK) level, neurologic examination, findings of muscle biopsy, muscle imaging findings and electrophysiologic features were extensively reviewed. Mutation of the GNE gene (9p13.3) was confirmed by DNA direct sequencing analysis in all patients. RESULTS: The mean onset age was 23.8+/-8.8 years (mean+/-SD). Patient serum CK levels were slightly to moderately elevated, ranging from 41 to 2610 IU. Among the patients, twelve patients were female and nine patients were male. Except for eight patients, all of the patients presented initially with only distal muscle weakness in the lower extremities. The most common mutation was V572L, followed by C13S. CONCLUSION: The clinical manifestations of our patients with GNE mutations varied. Among twenty-one patients, thirteen patients showed the typical GNE myopathy phenotype. There was no relationship between clinical features and site of mutation. Therefore, we suggest that neither homozygous nor compound heterozygous models are correlated with disease phenotype or disease severity.
Adolescent ; Adult ; Creatine Kinase/blood ; Distal Myopathies/diagnosis/*genetics/pathology ; Female ; Humans ; Male ; Multienzyme Complexes/*genetics ; Republic of Korea ; Sequence Analysis, DNA

OBJECTIVETo compare the clinical, pathological, laboratory test and follow-up data between familial and sporadic patients with distal myopathy with rimmed vacuoles (DMRV) and discuss the characteristics of this disorder in Chinese population.

METHODSThe clinical and pathological features, laboratory data and follow-up results of 33 sporadic and 4 familial cases of pathologically confirmed DMRV were summarized and compared retrospectively.

RESULTSThe patients age, onset age, or disease duration showed no significant difference between sporadic and familial cases; the onset pattern and affected muscle groups were also similar, but the sporadic cases showed more frequent dysmorphic features than the familial cases. The patients showed mild to moderate elevation of the muscle enzymes by one to three folds, and the familial patients had more significant elevation than the sporadic ones. No correlation was found between the disease duration and the level of muscle enzymes. The pathological findings were similar between the cases, and Gomori staining showed rimmed vacuoles and inclusion bodies without inflammatory cell infiltration. Follow-up results of 29 cases showed no significant difference between the two groups. The disease was slowly progressive and severely affected the quality of life of the patients, but did not produce obvious effect on the life expectancy.

CONCLUSIONThe clinical, pathological and laboratory data of Chinese DMRV patients are basically similar to those of Japanese cases. Sporadic cases tend to show more dysmorphic features than the familial ones, and occasional sporadic cases have early disease onset in early childhood.

Adult ; Asian Continental Ancestry Group ; Distal Myopathies ; classification ; genetics ; pathology ; Female ; Humans ; Inclusion Bodies ; pathology ; Male ; Pedigree ; Retrospective Studies ; Vacuoles ; pathology ; Young Adult

OBJECTIVETo investigate GNE gene mutations in 5 Chinese patients with distal myopathy with rimmed vacuoles (DMRV).

METHODSFive patients with typical clinical and pathological features of DMRV were studied. All the 11 coding exons and the flanking intron sequences of GNE gene were amplified by PCR and sequenced. Four family members of case 5 were also examined for GNE gene mutations.

RESULTSAll the patients were identified to have different GNE gene mutations: Cases 1-4 had complex heterozygous mutations and case 5 had homozygous mutation. Six reported mutations had been identified, including 1 nonsense mutation (p.R8X) and 5 missense mutations (p.D176V, p.I298T, p.A591T, P.A631V, and p.V696M). A novel mutation (c.317T>C, p.I106T) was identified in case 2.

CONCLUSIONThis is the first report of p.R8X, p.I298T, p.A591T and p.V696M mutations in GNE gene in Chinese population, and a novel mutation p.I106T was identified. These findings further expand the clinical and genetic spectrum of DMRV in China.

Adult ; Asian Continental Ancestry Group ; genetics ; Base Sequence ; DNA Mutational Analysis ; Distal Myopathies ; enzymology ; genetics ; Female ; Humans ; Male ; Molecular Sequence Data ; Multienzyme Complexes ; genetics ; Mutation ; genetics ; Mutation, Missense ; genetics ; Young Adult

Adolescent ; Adult ; Asian Continental Ancestry Group ; Cardiac Myosins ; genetics ; Child ; Creatine Kinase ; blood ; Distal Myopathies ; blood ; genetics ; Female ; Genetic Predisposition to Disease ; Humans ; Male ; Middle Aged ; Mutation ; genetics ; Mutation, Missense ; genetics ; Myosin Heavy Chains ; genetics ; Pedigree ; Polymorphism, Single Nucleotide ; 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