OBJECTIVETo analyze clinical characteristics of a combination of dystrophinopathies and Klinefelter's syndrome (karyotype 47, XXY) in one patient.

METHODThe patient was diagnosed as Duchenne muscular dystrophy (DMD) and Klinefelter's syndrome in Beijing Children's Hospital in March, 2013. The clinical manifestations, physical examinations and laboratory test results were analyzed respectively. The clinical characteristics of four cases reported previously were analyzed as well.

RESULTThe 8.5 years old boy presented with symptoms of walking disorder and developmental delay. The patient had facial dysmorphism, waddling gait, Gower's manoeuvre and enlarged calves.Serum creatine kinase level was 21 040 U/L, and he had mild intellectual impairment. Deletions of exons 49-54 of the dystrophin gene were found.Gene dosage analysis revealed a heterozygous deletion in his mother. Five cases have been reported till now, their age ranged from 3.5 to 18 years; 3 of them were DMD, while the other 2 cases were Becker muscular dystrophy (BMD). One of them, detected in pedigree study, whose weakness was minimal in contrast to the proband. The others came to the hospital because of walking disorder or developmental delay. All the patients had enlarged calves, some of them also had Gower's manoeuvre and waddling gait. The patients' height was between 3 rd and 50 th percentile, while 2 of them had facial dysmorphism.Some degree of mental impairment is usual. Their serum creatine kinase were 2 469-24 750 U/L.One of them was detected in pedigree study. Three of them were diagnosed by muscle biopsy, while in the other one mutation analysis was used.

CONCLUSIONThe combination of dystrophinopathies and Klinefelter's syndrome is quite rare, and has clinical features of these two diseases. Mutation analysis (or muscle biopsy) and karyotype analysis can finally diagnose the syndrome.

Child ; Creatine Kinase ; blood ; DNA Mutational Analysis ; Dystrophin ; genetics ; metabolism ; Exons ; genetics ; Gene Deletion ; Heterozygote ; Humans ; Intellectual Disability ; Klinefelter Syndrome ; complications ; diagnosis ; genetics ; Male ; Muscle Weakness ; etiology ; Muscular Dystrophy, Duchenne ; complications ; diagnosis ; genetics ; Mutation ; Pedigree

The aim of the present study was to explore the changes and roles of dystrophin and membrane permeability in hypoxic training. Seventy-two 8-week-old Sprague Dawley (SD) rats were randomly divided into 4 groups, normoxic non-train (NC), normoxic train (NT), hypoxic non-train (HC), and hypoxic train (HT) groups. The rats of each group were randomly divided into three subgroups, non-exhaustive, low-speed exhaustive test and high-speed exhaustive test subgroups. Rats in hypoxia groups lived and were trained in a condition of 12.7% oxygen concentration (equal to the 4 300 m altitude). NT and HT groups received 4 weeks of training exercise. Then the rats in all non-exhaustive subgroups were sacrificed, and gastrocnemii were sampled for the measurements of lactate dehydrogenase (LDH), succinatedehydrogenase (SDH), malate dehydrogenase (MDH) activities. Moreover, serum LDH activity was analyzed. Low-speed exhaustive test and high-speed exhaustive test subgroups received exhaustive tests with 20 (71% VO2max) and 30 m/min speed (86% VO2max), respectively, and their exhaustive times were recorded. The results showed that, compared with normoxic groups, the weights in hypoxia groups exhibited slower increase. The level of dystrophin in HT group without exhaustion test didn't change significantly. The muscle MDH activities were markedly affected by the different oxygen concentration, training and their interaction (P < 0.05), whereas the muscle LDH activities were only affected by the different oxygen concentration (P < 0.05). Serum LDH activities were affected by the interaction of the different oxygen concentration and training (P < 0.05), showing decreased muscle LDH and increased blood LDH activities. The exhaustion time were markedly affected by the different test speed, training and their interaction (P < 0.05), and also affected by the interaction of the different oxygen concentration and training (P < 0.05), but didn't affected by oxygen concentration. The exhaustive time of HT high-speed exhaustive test subgroup was more than NT high-speed exhaustive test subgroup in 30 m/min exhaustion test. Compared with NT high-speed exhaustive test subgroup, HT high-speed exhaustive test subgroup had an earlier fatigue in the test, but had a rapid recovery. These results suggested that hypoxic training can effectively increase the rats' high-speed exhaustive time. The mechanism may be related to an increase in serum LDH caused by the increased membrane permeability after hypoxic training.
Altitude ; Animals ; Dystrophin ; metabolism ; Fatigue ; Hypoxia ; L-Lactate Dehydrogenase ; metabolism ; Malate Dehydrogenase ; metabolism ; Muscle, Skeletal ; enzymology ; Physical Conditioning, Animal ; Rats ; Rats, Sprague-Dawley ; Succinate Dehydrogenase ; metabolism

Carrier woman of Duchenne muscular dystrophy (DMD) can mimic the inflammatory myositis in presenting symptoms. Two diseases should be differentiated by the clinical history, muscle biopsy and genetic study. There are few reports in which both histochemical and genetic study showed the possible link of overlapping inflammatory pathophysiology with dystrophinopathy. We report a 40-yr-old woman who presented with subacute proximal muscle weakness and high serum level of creatine kinase. She had a history of Graves' disease and fluctuation of serum liver aminotransferase without definite cause. MRI, EMG and NCV were compatible with proximal muscle myopathy. Muscle biopsy on vastus lateralis showed suspicious perifascicular atrophy and infiltration of mono-macrophage lineage cells complicating the diagnosis. Dystrophin staining showed heterogeneous diverse findings from normal to interrupted mosaic pattern. Multiple ligation probe amplification and X chromosome inactivation test confirmed DMD gene deletion mutation in exon 44 and highly skewed X inactivation.
Adult ; Creatine Kinase/blood ; Diagnosis, Differential ; Dystrophin/metabolism ; Echocardiography ; Exons ; Female ; Heterozygote ; Humans ; Magnetic Resonance Imaging ; Muscle Weakness ; Muscular Dystrophy, Duchenne/*diagnosis/genetics/pathology ; Myositis/diagnosis/genetics/pathology ; Transaminases/blood

OBJECTIVETo identify potential mutations in patients featuring Becker muscular dystrophy (BMD) and to enhance the understanding of non-deletion/duplication mutations of the dystrophin gene causing BMD.

METHODSClinical data of two patients affected with BMD were collected. Potential mutations in the dystrophin gene were screened with multiplex ligation-dependent probe amplification assay (MLPA). Biopsied muscle samples were examined with HE staining, immnostaining with anti-dystrophin antibody, and electronic microscopy.

RESULTSMLPA assay suggested that both cases were probably due to non-deletion/duplication mutations of the dystrophin gene. Light and electronic microcopy of skeletal muscle biopsies confirmed dystrophic changes in both patients. For patient A, immunostaining showed non-contiguous weak staining for most parts of sarcolemma. For patient B, immunostaining showed positive result with N-terminal anti-dystrophin antibody and negative result with C-terminal anti-dystrophin antibody.

CONCLUSIONFor patients with mild phenotypes but without dystrophin gene deletion/duplication, muscle biopsy and immunochemistry are helpful for diagnosis and prognosis.

Adolescent ; Adult ; Dystrophin ; genetics ; metabolism ; Humans ; Male ; Muscle, Skeletal ; pathology ; Muscular Dystrophy, Duchenne ; genetics ; metabolism ; pathology ; Mutation ; genetics

OBJECTIVEImmunohistochemistry using antibodies to dystrophin is the pathological basis for the differential diagnosis of Duchenne and Becker muscular dystrophy (DMD and BMD). In rare cases, however, labelling dystrophin on sarcolemma is equivocal and similar to that observed in controls. This makes the diagnosis of BMD difficult. This study aimed to explore the diagnostic value of neuronal nitric oxide synthase (nNOS) antibody for clinically suspected BMD.

METHODSImmunohistochemical staining was performed on muscle specimens of 5 cases of BMD with positive expression of Dys-C (3 cases had a confirmed diagnosis of BMD, 2 cases were clinically suspected as BMD) by using dystrophin and nNOS antibodies. Normal muscle specimens from the children with fracture were used as controls.

RESULTSCompared with the controls, the expression of Dys-R, Dys-C and Dys-N was markedly reduced and nNOS was not expressed on sarcolemma in the three cases of definitely diagnosed BMD. The two cases of clinically suspected as BMD had a complete absence of sarcolemmal nNOS, even if had a similar expression of dystrophin on sarcolemma to the controls.

CONCLUSIONSnNOS antibody staining can be used for a definite diagnosis in children with clinically suspected BMD who have the almost normal expression of dystrophin.

Child ; Child, Preschool ; Dystrophin ; analysis ; chemistry ; Humans ; Immunohistochemistry ; Infant ; Muscular Dystrophy, Duchenne ; diagnosis ; metabolism ; Nitric Oxide Synthase Type I ; analysis

To explore the changes and regulation mechanism of dystropin and desmin under muscle injury without mechanic stress, 40 male Sprague-Dawley rats were randomly divided into 5 groups, which included normoxia control and hypoxia groups for 1, 2, 4 and 7 d with 10% O2. Two rats from each group were examined for sarcolemma integrity using Evans blue dye (EBD) and EBD-positive fiber typing by metachromatic dye-ATPase method. The rest six rats from each group were analyzed for the changes of protein content and gene expression using Western blot, RT-PCR and fluorescence assays. The results showed that the EBD-positive muscle fibers, mainly type IIA and type IIB, appeared at 1 d after hypoxia exposure. Both the ratio of EBD-positive cell and the mean fluorescence density were significantly higher in hypoxia groups than those in control group (P<0.05). The contents of dystrophin and desmin fluctuated after hypoxia exposure, increased at 1 d, decreased at 2 d, increased dramatically again at 4 d, and returned to a normal level at 7 d. Consistently, the gene expression began to increase significantly after 2 d. The total activity of calpain was significantly higher in hypoxia groups at 1, 4 and 7 d. Significantly higher levels of HSP70 and HSP90 were also observed at 4 and 7 d, respectively (P<0.05). These results suggest that the mechanical stress is not the only cause of damage of sarcolemma membrane integrity. In contrast to eccentric contraction, hypoxia-induced muscle damage is not accompanied by the loss of dystrophin and desmin. The types of muscle fibers recruited by motor units and the activities of calpain may be important in hypoxia-induced damage of sarcolemma membrane integrity.
Animals ; Calpain ; metabolism ; Desmin ; metabolism ; Dystrophin ; metabolism ; Hypoxia ; metabolism ; physiopathology ; Male ; Muscle, Skeletal ; metabolism ; pathology ; Rats ; Rats, Sprague-Dawley ; Sarcolemma ; pathology

OBJECTIVETo investigate the differentiation of rat bone marrow mesenchymal stem cells (MSCs) into myocytes and their expression of dystrophin/utrophin after transplantation in mdx mice.

METHODSBrdU-labeled fifth-passage rat MSCs were transplanted in mdx mice with previous total body gamma irradiation (7 Gy). At 4, 8, 12 and 16 weeks after the transplantation, the mice were sacrificed to detect dystrophin/BrdU and utrophin expressions in the gastrocnemius muscle using immunofluorescence assay, RT-PCR and Western blotting. Five normal C57 BL/6 mice and 5 mdx mice served as the positive and negative controls, respectively.

RESULTSFour weeks after MSC transplantation, less than 1% of the muscle fibers of the mdx mice expressed dystrophin, which increased to 15% at 16 weeks. Donor-derived nuclei were detected in both single and clusters of dystrophin-positive fibers. Some BrdU-positive nuclei were centrally located, and some peripherally within myofibers. Utrophin expression decreased over time after transplantation.

CONCLUSIONThe myofibers of mdx mice with MSC transplantation express dystrophin, which is derived partially from the transplanted MSCs. Dystrophin expression from the transplanted MSCs partially inhibits the upregulation of utrophin in mdx mouse muscle, showing a complementary relation between them.

Animals ; Bone Marrow Cells ; cytology ; Cell Differentiation ; physiology ; Dystrophin ; genetics ; metabolism ; Mesenchymal Stem Cell Transplantation ; Mesenchymal Stromal Cells ; cytology ; Mice ; Mice, Inbred C57BL ; Mice, Inbred mdx ; metabolism ; Muscle Fibers, Skeletal ; cytology ; metabolism ; Muscular Dystrophy, Animal ; metabolism ; therapy ; Rats ; Utrophin ; metabolism

Recent reports indicate that the dysbindin gene located on chromosome 6p22.3 is a major susceptibility gene for schizophrenia. In the brain, the dysbindin gene may influence glutamatergic neurotransmission by multiple post- and pr- synaptic mechanisms. This paper reviews the research progress on the dysbindin gene in schizophrenia, including the dysbindin gene and its product, the possible pathogenic mechanisms, the association study of the dysbindin gene with schizophrenia, and the cognitive decline caused by the dysbind in variations.
Brain ; metabolism ; Carrier Proteins ; genetics ; physiology ; Cognition Disorders ; genetics ; physiopathology ; Dysbindin ; Dystrophin-Associated Proteins ; Genetic Predisposition to Disease ; Genotype ; Humans ; Polymorphism, Single Nucleotide ; Schizophrenia ; genetics ; metabolism ; pathology

OBJECTIVETo explore the structural and functional changes of dystrophin molecule after exon 3 deletion.

METHODSThree-dimensional models of dystrophin comprising the major domains were established before and after exon 3 deletion using SWISS-MODEL server. The motifs and structural domains of dystrophin after exon 3 deletion were searched in Pfam database, and the crystal structure of the actin-binding domain in the dystrophin molecule was analyzed using Rasmol software.

RESULTSTorsion of the N-terminal actin-binding domain occurred in the dystrophin molecule after deletion of exon 3. Homology analysis based on Pfam database searches indicated that following exon 3 deletion, the Bit score of the first calponin homology (CH1) domain was decreased from 108 to 36.5 while its expectation value increased from 2.3e-9 to 8.1e-8. The deletion also resulted in the absence of the spiral region C from the CH1 domain.

CONCLUSIONExon 3 deletion in the dystrophin-coding sequence decreases the stability of CH1 domain and prevents the formation of the junction interface where dystrophin binds to actin. The bioinformatics approach provides a new alternative for investigation of the pathogenesis of DMD pathogenesy investigation.

Dystrophin ; chemistry ; genetics ; metabolism ; Exons ; genetics ; Humans ; Models, Molecular ; Muscular Dystrophy, Duchenne ; genetics ; metabolism ; Protein Binding ; Protein Conformation ; Protein Structure, Tertiary ; Sequence Deletion ; Structure-Activity Relationship

OBJECTIVETo construct the recombinant plasmid containing human microdystrophin cDNA, and study the microdystrophin expression in vivo and in vitro.

METHODSMicrodystrophin cDNA was obtained from recombinant plasmid pBSK-MICRO digested with restrictive endonuclease Not I, the product was inserted into plasmid pVAX1, resulting in pAMICDYS. And then 3T3 cells were transfected with pAMICDYS. Forty-eight hours after transfection, the expression of the microdystrophin was detected by reverse transcription-polymerase chain reaction (RT-PCR) and immunocytochemistry. Finally, TA muscles of mdx mice were injected with the recombinant plasmid pAMICDYS through i.m. and the pathological change of TA was evaluated by histology, and the expression of microdystrophin in mdx TA was detected by immunohistochemical analysis.

RESULTSThe recombinant plasmid containing human microdystrophin cDNA was constructed successfully. The recombinant plasmid was proved to be able to express microdystrophin protein both in vivo and in vitro. Moreover, treatment of the TA of mdx mice with the recombinant plasmid could decrease the number of centrally nucleated myofibers.

CONCLUSIONRecombinant plasmid containing the microdystrophin gene was constructed successfully, and it could express microdystrophin protein both in vivo and in vitro. It provides basis for further study on microdystrophin as a target gene to treat Duchenne muscular dystrophy (DMD) by electrotransfer, i.v, arterial injection and combining with other exogenous gene to enhance microdystrophin expression.

Animals ; Cloning, Molecular ; DNA Restriction Enzymes ; metabolism ; DNA, Complementary ; genetics ; metabolism ; DNA, Recombinant ; genetics ; metabolism ; Dystrophin ; genetics ; Gene Expression ; Genetic Engineering ; Genetic Therapy ; Genetic Vectors ; metabolism ; Humans ; Immunohistochemistry ; Mice ; Muscular Dystrophy, Duchenne ; genetics ; metabolism ; therapy ; NIH 3T3 Cells ; Plasmids ; genetics ; Reverse Transcriptase Polymerase Chain Reaction ; Transfection