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

PURPOSE: The objective of this study is to evaluate the value of multiple-PCR as a diagnostic modality in detection of dystrophin gene deletion by observing its detection rate and concordance rate with clinical diagnosis. MATERIALS AND METHODS: Fifty-two male patients who were clinically diagnosed as DMD or BMD (Duchenne or Becker muscular dystrophy) and received multiple-PCR from 1994 to 1997 at our center were included in this study. The relationship between clinical phenotype and the location of gene deletion were studied using reading-frame rule. Dystrophin protein analysis by immunocyto-chemical technique was done in 7 cases with negative multiplex-PCR. RESULTS: Out of fifty-two patients, thirty-four were DMD and eighteen as BMD clinically. Multiplex-PCR revealed dystrophin gene deletion in 19 patients (36%) consisting of twelve DMD and seven BMD cases. The locations of the gene deletion coincide with the clinical phenotype in 17 cases (89%). Among the 7 cases that underwent dystrophin protein analysis, 3 DMD and 2 BMD were confirmed. CONCLUSIONS: Though no substantial gene deletion detection rate was observed in this study, multiple-PCR could be used as a first-line diagnostic tool in detecting dystrophin gene deletion in DMD/BMD patients based on its high concordance rate with phenotype and favorable patient compliance and convenience.
Diagnosis* ; Dystrophin ; Gene Deletion ; Humans ; Male ; Muscular Dystrophy, Duchenne* ; Patient Compliance ; Phenotype

OBJECTIVE: To carry out pedigree analysis for a rare child with comorbid X-linked ichthyosis (XLI) and Duchenne muscular dystrophy (DMD). METHODS: Whole exome sequencing (WES) and multiple ligation-dependent probe amplification (MLPA) were used to detect potential deletions in the STS and DMD genes. RESULTS: The proband was found to harbor hemizygous deletion of the STS gene and exons 48 to 54 of the DMD gene. CONCLUSION The child has comorbid XLI and DMD, which is extremely rare.
Child ; Dystrophin/genetics* ; Exons ; Gene Deletion ; Genetic Testing ; Humans ; Ichthyosis/genetics* ; Muscular Dystrophy, Duchenne/genetics* ; Mutation

OBJECTIVETo conduct genetic diagnosis for a family in which no exonic deletions and duplications of the dystrophin gene were detected.

METHODSPotential exonic deletions and duplications of the dystrophin gene were initially analyzed with using multiplex ligation-dependent probe amplification (MLPA). Subsequently, all of the 79 exons of the dystrophin gene of the proband and a pregnant woman from the family were analyzed with PCR amplification and DNA sequencing. Following identification of the causative mutation, prenatal diagnosis was provided.

RESULTSMLPA analysis had detected no exonic deletions and duplications of the dystrophin gene. Sequence analysis has identified a C>T mutation on the 22nd nucleotide position of the 70th exon of the dystrophin gene (c.10108 C>T), which has replaced the codon CGA to a stop codon (TGA). The patient's mother and sister were both heterozygous for the same mutation. Upon prenatal diagnosis, the fetus was found to be positive for the Y chromosome sex-determining gene (SRY) and has carried above mutation. The result of short tandem repeat linkage analysis also confirmed that the fetus has inherited the mutant X chromosome.

CONCLUSIONThe causative mutation of the dystrophin gene has been discovered in an affected family, which has enabled prenatal diagnosis of the disease.

Child, Preschool ; Dystrophin ; genetics ; Exons ; Gene Deletion ; Gene Duplication ; Humans ; Male ; Microsatellite Repeats ; Multiplex Polymerase Chain Reaction ; Mutation

OBJECTIVETo set up a fluorescent in situ hybridization (FISH) based method to detect the gene-deleted female carriers of Duchenne/Becker muscular dystrophy (DMD/BMD).

METHODSMultiplex polymerase chain reaction was used to identify the gene deletion DMD/BMD probands and their female relatives were checked by double-color FISH.

RESULTSTwo probands whose exon 46 of dystrophin gene was deleted, one had a positive pedigree and the other was a sporatic patient. In the case of the positive pedigree, four carriers were detected. In the case of the sporatic family, FISH showed that the mother of the proband was a somatic mosaicism.

CONCLUSIONCombined with multiplex PCR, double-color FISH is a simple, fast, directly visual and accurate method. It is feasible to identify the carrier status of the female relatives of the gene deletion DMD/BMD probands. The detection of the somatic mosaicism is a prominent feature of FISH.

Dystrophin ; genetics ; Female ; Gene Deletion ; Humans ; In Situ Hybridization, Fluorescence ; methods ; Male ; Muscular Dystrophy, Duchenne ; diagnosis ; genetics ; Polymerase Chain Reaction

OBJECTIVE: To carry out genetic testing and prenatal diagnosis for a family affected with Duchenne muscular dystrophy (DMD). METHODS: Multiplex ligation dependent probe amplification (MLPA) was used to detect potential deletion and duplication of the Dystrophin gene. Haplotype analysis was performed using five short tandem repeat polymorphism loci (3'-STR, 5'-STR, 45-STR, 49-STR, 50-STR of the DMD gene. RESULTS: A same deletional mutation (exons 51-55) of the DMD gene was detected in two brothers but not in their mother. The patients and fetus have inherited different haplotypes of the Dystrophin gene from their mother, suggesting that the fetus was unaffected. CONCLUSION The mother was very likely to harbor germline mosaicism for the Dystrophin gene variant. Genetic testing of peripheral blood samples cannot rule out germline mosaicism in the mother. Prenatal diagnosis should be provided for subsequent pregnancies in this family.
Dystrophin ; genetics ; Exons ; Female ; Gene Deletion ; Germ-Line Mutation ; Humans ; Male ; Mosaicism ; Muscular Dystrophy, Duchenne ; genetics ; Pregnancy ; Prenatal Diagnosis

OBJECTIVE: To discuss the value of chromosomal microarray analysis (CMA) for the identification of DMD gene deletions during prenatal diagnosis. METHODS: G-banded karyotyping and CMA were performed on fetuses with ultrasonographic soft markers but no family history for Duchenne/Becker muscular dystrophy (DMD/BMD). Denaturing high-performance liquid chromatograghy (DHPLC) was used to detect DMD gene mutations in umbilical cord blood and peripheral blood samples from the mothers. RESULTS: For fetus 1, analysis of amniocytes showed a normal karyotype, while CMA detected a 119 kb deletion at Xp21.1 (32 565 489 - 32 681 461), which encompassed exons 10 to 16 of the DMD gene. The result was confirmed by DHPLC analysis. The mother was found to have loss of heterozygosity in the same region. For fetus 2, karyotyping of amniocytes also showed a normal male karyotype, while CMA detected a 254 kb deletion at Xp21.1 (32 104 604 - 32 358 874), which encompassed exons 41 to 44 of the DMD gene. The same deletion was not detected in the mother. DHPLC analysis confirmed the presence of both deletions. CONCLUSION Two fetuses harboring DMD gene deletions but without a family history were discovered. CMA can improve the efficiency for detecting single gene diseases caused by deletions.
Dystrophin ; genetics ; Exons ; Female ; Fetus ; Gene Deletion ; Humans ; Incidental Findings ; Male ; Microarray Analysis ; Muscular Dystrophy, Duchenne ; genetics ; Pregnancy

OBJECTIVE: To find correlations between the deletion of dystrophin gene and cognitive status in Duchenne muscular dystrophy (DMD). METHOD: Cognitive abilities of 49 DMD children with dystrophin deletion were tested. Korean Wechsler Intelligence Scale for children was used to evaluate the cognitive status in DMD. Gene deletion was classified into two groups according to the location of the rearrangement (proximal region: central and 3' region of the gene). RESULTS: Molecular study by multiplex PCR (Polymerase Chain Reaction) of dystrophin exons was performed to identify 49 deletions in the 110 DMD patients. 13 out of 49 DMD were mentally impaired. In patients with distal deletions, total IQ (Intelligence Quotient) score was lower than the those with proximal deletions; which was not statistically significant. And the difference of the verbal and performance intelligence scale was not statistically significant. But comparisons of molecular and neuropsychological features showed that deletions localized in the central and 3' regions of the gene were preferentially associated with the mental impairement. CONCLUSION: We concluded that deletions in the distal portions of the gene were more related to the mental retardation, although deletions with variable locations might lead to cognitive impairments.
Child ; Cognition* ; Dystrophin* ; Exons ; Gene Deletion ; Humans ; Intellectual Disability ; Intelligence ; Multiplex Polymerase Chain Reaction ; Muscular Dystrophy, Duchenne*

OBJECTIVE: To study the association between clinical phenotypes and genotypes in children with Becker muscular dystrophy (BMD)/Duchenne muscular dystrophy (DMD) so as to provide a theoretical basis for disease management, gene therapy, and prenatal diagnosis. METHODS: A retrospective analysis was performed for the clinical data and gene detection results of 52 children with BMD/DMD. Multiplex ligation-dependent probe amplification (MLPA) was used to detect the DMD gene. The children with negative results of MLPA were further screened by exon chip capture combined with next-generation sequencing (NGS). The mothers of 20 probands were validated by sequencing. RESULTS: The pathogenic genes for BMD/DMD were detected in 50 children by MLPA and NGS, with a detection rate of 96%. Among the 52 children, 36 (69%) had gene deletion, 7 (13%) had duplication, and 7 (13%) had micromutation. Among the 43 children with deletion/duplication, 32 had DMD and 11 had BMD; 37 children (86%) met the reading frame rule, among whom 27 (96%) had DMD and 10 (67%) had BMD. All 7 children with micromutation had DMD. CONCLUSIONS The reading frame rule has an extremely high predictive value for DMD but a limited predictive value for BMD.
Child ; Dystrophin ; Female ; Gene Deletion ; Genotype ; Humans ; Multiplex Polymerase Chain Reaction ; Muscular Dystrophy, Duchenne ; Mutation ; Phenotype ; Pregnancy ; Retrospective Studies

OBJECTIVE: To identify the etiology of a patient with severe symptoms of DMD and to trace its pathogenic gene, so as to provide a basis for genetic counseling and clinical intervention. METHODS: Multiple ligation-dependent probe amplification (MLPA) technique was used to analyze exon deletion/repetitive variant of DMD gene, and further analysis was performed by chromosome G-banding, fluorescence in situ hybridization (FISH) and SNP array analysis. RESULTS: The MLPA results of the proband showed that the exon 1-79 of DMD gene were deleted, the G-banding karyotype of blood sample was 46, XY, and the deletion of the short arm of X chromosome was found by FISH. SNP array results showed that 5.8Mb (29 628 158-35 434 714) deletion occurred in the Xp21.2p21.1 region of X chromosome, and the patient was diagnosed as the contiguous deletion syndrome involving the genes of IL1RAPL, MAGEB1-4, ROB, CXorf2, GM, AP3K7IP, FTHL1, DMD, FAM47A, TMEM47, and FAM47B. CONCLUSION The exact pathogenic site of this family is the deletion of 5.8 Mb (29 628 158-35 434 714) in the Xp21.2p21.1 region of X chromosome, which can be used for prenatal diagnosis. High resolution SNP array technique plays an important role in detecting potential chromosome abnormalities in patients.
Dystrophin/genetics* ; Exons ; Female ; Gene Deletion ; Humans ; In Situ Hybridization, Fluorescence ; Muscular Dystrophy, Duchenne/genetics* ; Pregnancy ; Prenatal Diagnosis