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

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

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

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.

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*

Recently, through the development of the primer extension preamplification(PEP) method which amplifies the whole genome, simultaneous multiple DNA analysis has become possible. Whole genome from each single cell can be amplified using 15 base oligonucleotide random primer. The greatest advantage of PEP-PCR is the ability to investigate several loci simultaneously and confirm results by analysing multiple aliquots for each locus. This technique led to the development of preimplantation genetic disease diagnosis using blastomere from early embryo, sperm, polar body and oocyte. In this study, we applied PEP-PCR in 20 cases of single amniocyte and 20 cases of single chorionic villus cell for the clinical application of the prenatal and preimplantational genetic diagnosis. We analysed 7 gene loci simultaneously which are 46, 47 exons related to dystrophin gene, two VNTR (variable number tandem repeat) markers using 5'toysIII, 3'CA related to dystrophin gene and DYZ1, DYZ3, DYS14 regions on chromosome Y. In all the tests, 97.5% of PEP-PCR amplifications with single cells were successful. We obtained 38/40 (95%) accuracy in gender determination through chromosome analysis comparison. Therefore, these results have significant implications for a sperm or oocyte analysis and prenatal or preimplantational genetic diagnosis.
Blastomeres ; Chorionic Villi ; Diagnosis ; DNA ; Dystrophin* ; Embryonic Structures ; Exons ; Genome ; Oocytes ; Polar Bodies ; Spermatozoa

BACKGROUND: Recent genetic analyses have shown that Miyoshi myopathy (MM) is caused by a mutation in the DYSF, which induces the dysfunction of dysferlin. We identified the deficiency of dysferlin by immunohistochemistry and Western blot in four patients with clinically diagnosed MM, and investigated the clinical and pathological characteristics of MM. METHODS: A muscle biopsy was performed in four patients who were diagnosed with MM by clinical and electrophysiological study. Immunostaining of muscle specimens for dyferlin, dystrophin, alpha, beta, gamma, sigma-sarcoglycan, beta-dystroglycan, and caveolin-3 were performed in all four patients. We analyzed the quantitative analysis for dysferlin by Western blot in three of four patients. RESULTS: All four patients showed clinical onset during adolescence or early adulthood (15-26 year old), a slowly progressive course, and a relatively high serum creatine kinase level (2240-6400 IU/L). Routine pathological studies showed non-specific myopathic changes. On immunocytochemistry, there was negative immunoreacticity for dysferlin on muscle specimens in all patients. The immunoreactivities for dystrophin, alpha, beta, gamma, sigma-sarcoglycan, beta-dystroglycan, and caveolin-3 were normal. On Western blotting, complete loss of dysferlin was noted in all three patients with MM CONCLUSIONS: Identification of isolated deficiency of dysferlin on immunocytochemistry or Western blot is important for the confirmative diagnosis of MM.
Adolescent ; Biopsy ; Blotting, Western* ; Caveolin 3 ; Creatine Kinase ; Diagnosis ; Dystroglycans ; Dystrophin ; Humans ; Immunohistochemistry ; Muscular Diseases*

OBJECTIVETo clarify the nature of a DMD splice acceptor mutation c.2381-3T>C.

METHODSGenomic DNA was extracted from 5 members of a family affected with DMD. For an obligatory carrier, after excluding gross deletion and duplication of the DMD gene with multiplex ligation-dependent probe amplification (MLPA) method, all coding and splice site sequences of the DMD gene were analyzed with Next Generation Sequencing followed by confirmation with targeted Sanger sequencing. Mutations of the carrier were detected in other 4 members. For the splice site mutation, mini-gene was constructed and expressed in vitro to detect the number of transcript and cDNA sequence.

RESULTSA known nonsense mutation (c.8038C>T, p.Arg2680Ter) was identified in the carrier, her sister and the mother. The rest 4 members, except for the mother from the first generation, have all carried the c.2381-3T>C mutation. The latter has been described as a splice site mutation to cause DMD. One of 135 male adults without DMD was also detected to have carried the c.2381-3T>C mutation. No additional transcript was produced by the mini-genes containing c.2381-3T>C mutation.

CONCLUSIONThe c.8038C>T（p.Arg2680Ter）mutation of DMD gene probably underlies the disease in this family. The presence of the c.2381-3T>C mutation in a asymptomatic male and a non-DMD male control, together with the normal in vitro expression of the mini-gene carrying the c.2381-3T>C, strongly suggested that the c.2381-3T>C mutation collected in the Human Gene Mutation Database is a rare SNP without significant pathogenicity.