Rationale: Duchenne muscular dystrophy (DMD) is a disease that primarily manifests in the early stages of life and progressively affects muscle strength resulting in quadriparesis and ultimately resulting in premature death secondary to cardiac or respiratory failure. DMD is the most common x-linked genetic disorder in children that is because of an alteration of a protein called “dystrophin” which is responsible for strengthening muscle fibers and protecting them from injury as muscles contract and relax. Objective: To highlight the case of a 19-year-old male who was diagnosed with DMD at 8 years of age and treated with oral corticosteroid and rehabilitation. Case: We present the case of a 19-year-old male who developed difficulty climbing stairs and was diagnosed with DMD at 8 years old with the use of clinical exome sequencing. Corticosteroid therapy was initiated and rehabilitation perpetuated which dramatically improved his life expectancy. Discussion and Summary Clinical exome sequencing was employed on our patient to confirm the diagnosis of DMD from other neuromuscular and neurodegenerative diseases. Most cases of DMD succumb to cardiopulmonary arrest before reaching adulthood; however, this case exemplifies DMD from other cases since our patient was able to prolong his life with continuation of oral corticosteroid and rehabilitation and in the absence of extensive life support.
Dystrophin ; Mortality, Premature

A majority deletion of 27 exons expanding from 8-34 at rod domain of dystrophic gene was identified in a Duchene Muscular Dystrophy (DMD) patients. Polymerase chain reaction (PCR) was used to analyze the deletion. The deletion caused an out of frame mutation leading to nonsense mutation which early stops code in exon 35 of dystrophic gene. The DMD gene was analyzed at both genomic DNA and mRNA levels. Identification of deletion at mRNA level is very useful for rapid diagnosis of DMD patients and avoid missing some mutations that we can’t identify at DNA level
Muscular Dystrophy, Duchenne ; Dystrophin ; Genes

Background: Production of semi-functional dystrophin protein from the dystrophin gene encoded with a premature stop codon has been shown to modify the severe phenotype of Duchenne Muscular Dystrophy (DMD). The mutation of the dystrophin gene affects the process of complete mRNA and is important in gene therapy. Objective: To analyze the mutation of dystrophin gene in DMD cases. Subjects and methods: A patient with diagnosed with DMD when he was 2 years old, and at age 9, he was completely disabled and had to use a wheelchair. DNA and total RNA were extracted from fresh peripheral blood; cDNA was synthesized by transcript polymerase chain reaction (RT - PCR). PCR, nested PCR or sequence methods were used to determine the mutation of the dystrophin gene. Results: A nonsensical mutation (E638) due to a single nucleotide change in exon 17 of the dystrophin gene (GAA2047TAA) was identified. This mutation affects mRNA splicing process and induces complete exon 17 skipping. Conclusion: Patients, who had E638X mutation with exon 17 deletion in the dystrophin gene, had clinical symptoms of Becker Muscular Dystrophy (BMD). This discovery as a potential target for therapeutic strategies for DMD, to change the severe phenotype of DMD to a milder phenotype (BMD), in order to improve clinical conditions for the patients.
Duchenne muscular dystrophy ; dystrophin gene

OBJECTIVETo study the human dystrophin gene molecular deletion mechanism, we analyzed breakpoint regions within junction fragments of deletion-type patients and investigated whether the dystrophin gene's intron structure might be related to intron instability.

METHODSJunction fragments corresponding to exon 46 and 51 deletions were cloned. The breakpoint regions were sequenced, and the features of introns with available Genebank sequences were analyzed.

RESULTSAn analysis of junction fragment sequences corresponding to exon 46 and 51 deletions showed that all 5' and 3' breakpoints are located within repeat sequences. No small insertions, small deletions, or point mutations are located near the breakpoint junctions. By analyzing the secondary structure of the junction fragments, we demonstrated that all junction fragment breakpoints are located in non-matching regions of single-stranded hairpin loops. A high concentration of repetitive elements is found to be a key feature of many dystrophin introns. In total, 34.8% of the overall dystrophin intron sequences is composed of repeat sequences.

CONCLUSIONRepeat elements in many dystrophin gene introns are the key to their structural bases and reflect intron instability. As a result of the primary DNA sequences, single-stranded hairpin loops form, increasing the instability of the gene, and forming the base for breaks in the DNA. The formation of the single-stranded hairpins can result in reattachment of two different breakpoints, producing a deletion.

Dystrophin ; genetics ; Humans ; Introns ; genetics ; Sequence Deletion

Child ; Consensus ; Dystrophin ; Humans ; Muscular Dystrophies/rehabilitation*

The dystrophin gene is the largest human gene. Mutations in this gene cause Duchenne muscular dystrophin (DMD) disease. This is complex genomic unit exhibiting many errors splicing during mRNA process. More than 10 alternative splicing products have been identified in the 5' region of the dystrophin gene. In this study, two dystrophin transcripts including one containing exon 2 and exon X duplications, other one containing single exon 2 duplication were identified in peripheral blood lymphocytes of DMD case. Interestingly, genomic Southern blot analysis ruled out the hypothesis of duplication of dystrophin at exon 2. Therefore, these data suggested that exon 2 duplication transcripts were likely generated by trans-splicing event that occurring during the mARN maturation in which RNA segments of two independent transcripts are spliced together to generate a new mRNA species. However, the mechanisms modulating the trans-splicing activity of the dystrophin exon 2 remain to be clarified.
Muscular Dystrophy, Duchenne, Dystrophin, Genes, DMD protein, human

PURPOSE: Restriction fragment length polymorphism-polymerase chain reaction (RFLP-PCR) is a widely accepted method for carrier detection of Duchenne and Becker muscular dystrophy (DMD and BMD) . This study was done to evaluate the clinical value of linkage analysis of RFLP-PCR using five polymorphic markers selected and the heterozygote frequency of those markers in DMD/BMD patients and their family members. MATERIALS AND METHODS: RFLP-PCR test was performed in twenty clinically diagnosed male DMD/BMD patients from 13 families who have been confirmed to have dystrophin gene defect from 1994 to 1997 and their 47 female family members and the results were evaluated by linkage analysis to detect carriers. RESULTS: The heterozygote frequency of pERT 87-15/XmnI, pERT87-15/BamHI, pERT87-8/TaqI, 5'-dysIII (CA) and 3'-dys (CA) markers were 55%, 49%, 45%, 32% and 26% respectively. Fourty-four (91%) out of 47 female family members had heterozygosity to at least one of those five markers. Since the obligate carriers from two families showed homozygocity to all five markers, carrier detection was possible in eleven families (85%) by the linkage analysis. CONCLUSION: RFLP-PCR using markers with high heterozygote frequency could be the first line modality of carrier detection that is crucial in genetic counseling of DMD/BMD patients and their families.
Dystrophin ; Female ; Genetic Counseling* ; Heterozygote ; Humans ; Male ; Muscular Dystrophy, Duchenne*

OBJECTIVETo diagnose muscular dystrophy using Western blot (WB) by improving the method of the protein extraction.

METHODFirstly,we compared the effect of different sample buffer solutions and processing Methods on the extraction of muscle protein in rats,then selected the appropriate extracting method and the process of the muscular protein.

RESULTSWe put the selected sample buffer into the micro-sample,then mixed. The concentration of the extracting protein was much more,and the loss during the process was much less. We extracted enough protein in 62 cases. The protein bands were showed clearly by WB,and the abnormal protein bands were shown in some patients. Compared with the Results of immunohistochemical staining detected the severe abnormal expressions of Dys-R,Dys-C,and Dys-N in the specimens,we did not detect the corresponding target band in WB. We detected the target protein band of the specimens were abnormal position,light or normal staining in WB,while Dys were mildly expressed in immunohistochemical staining.

CONCLUSIONSThe improved protein extraction method can save the muscle tissue,and the protein bands can be used for diagnosing the muscular dystrophy. For clinically suspected patients with dystrophinopathy,if normal or mild deficiency is shown by immunohistochemistry,WB should be applied to detect the dystrophin protein band.

Animals ; Blotting, Western ; Dystrophin ; Humans ; Immunohistochemistry ; Muscular Dystrophies ; Protein Transport ; Rats ; Staining and Labeling

OBJECTIVETo explore the correlation between genotypes and phenotypes in Chinese patients with pseudohypertrophic muscular dystrophy.

METHODSPatients with Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) were diagnosed clinically. Multiplex ligation-dependent probe amplification (MLPA) were performed to detect potential DMD gene mutations. The results were analyzed statistically.

RESULTSAmong 280 patients, 238(85.0%) were diagnosed with DMD, 35(12.50%) were diagnosed with BMD and 7(2.5%) were diagnosed with intermediate muscular dystrophin (IMD). Among these, 252(92.31%) were in-frame mutations, and 21(7.69%) were out-of-frame mutations. Twelve patients with DMD have carried in-frame mutations, 9 with BMD have carried frame-shift mutations, and 7 IMD patients have carried frame-shift mutation.

CONCLUSIONMost of the genotypes and phenotypes of DMD have complied with the reading-frame hypothesis. Patients with BMD with frame-shift mutations may facilitate understanding of the pathogenesis of DMD, and provide a theoretical basis for clinical therapy.

Dystrophin ; genetics ; Exons ; Genetic Association Studies ; Genotype ; Humans ; Muscular Dystrophy, Duchenne ; diagnosis ; genetics ; Mutation ; Phenotype

OBJECTIVETo investigate the clinical and lab features of sibling brother and sister both with Duchenne muscular dystrophy (DMD).

METHODSWe conducted comprehensive clinical and lab investigations including the test of serum enzymes, electromyography (EMG), electrocardiography, color Doppler echocardiography, HE staining of skeletal muscles, immunohistochemical study of dystrophin and utrophin, multiple ligation probe amplification (MLPA) on exon 1-79 of dystrophin gene, and short tandem repeat-poly- merase chain reaction of CA repeats located in dystrophin gene.

RESULTSThese two patients were confirmed to suffer from DMD. They were characterized by typical features of DMD including typical clinical manifestations, increased serum enzymes, EMG presenting myogenic impairment, HE staining presentation belonging to DMD, negative dystrophin in brother, and inconstantly positive on the sarcolemma of sister. Furthermore, no deletion or duplication was found in the 1-79 exons of dystrophin gene. The suffering brother and sister carried the same maternal X chromosome.

CONCLUSIONSCarriers of DMD gene show typical clinical and laboratory manifestations of DMD. Comprehensive examinations should be performed for such carriers.

Dystrophin ; genetics ; Female ; Genetic Linkage ; Heterozygote ; Humans ; Male ; Muscular Dystrophy, Duchenne ; genetics ; metabolism ; physiopathology ; Siblings