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

OBJECTIVE: To summarize the result of genetic testing and therapeutic prospect of 2042 unrelated Chinese pedigrees affected with Duchenne/Becker muscular dystrophy (DMD/BMD) from a single center from 2005 to 2019. METHODS: Peripheral blood samples of the pedigrees were collected for the detection of DMD gene variants with combined multiple ligation-dependent probe amplification (MLPA), next generation sequencing (NGS) and Sanger sequencing. RESULTS: DMD and BMD have respectively accounted for 78.60% and 21.40% of the pedigrees, which included 33 female probands. Variants of the DMD gene were detected in 1986 pedigrees (97.26%). Large deletions, duplications and small-scale mutations have respectively accounted for 71.85%, 8.76% and 19.39%. Common deletions and duplications have included deletion of exons 45-50 and duplications of exon 2, while no hot spot was found with small-scale mutations. For 1595 pedigrees affected with DMD, 935 (58.62%) were hereditary and 660 (41.38%) were de novo in origin. 34.28% (700/2042) of the patients had symptoms which could be relieved by gene therapy. CONCLUSION This has been the largest single-center study of DMD pedigrees, which has attained definite diagnosis in 97.26% of the patients. The results have enabled genetic counseling and prenatal diagnosis for the affected families upon their subsequent pregnancies, enriched the spectrum of DMD gene variants, as well as facilitated study of the mechanism of DMD gene mutations and exploration of clinical treatment.
China ; Dystrophin/genetics* ; Exons/genetics* ; Female ; Gene Deletion ; Genetic Testing ; Humans ; Muscular Dystrophy, Duchenne/therapy* ; Mutation ; Pedigree ; Pregnancy

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

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 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

BackgroundDuchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) are common X-linked recessive neuromuscular disorders caused by mutations in dystrophin gene. Multiplex polymerase chain reaction (multiplex PCR) and multiplex ligation-dependent probe amplification (MLPA) are the most common methods for detecting dystrophin gene mutations. This study aimed to contrast the two methods and discern the genetic characterization of patients with DMD/BMD in Eastern China.

MethodsWe collected 121 probands, 64 mothers of probands, and 15 fetuses in our study. The dystrophin gene was detected by multiplex PCR primarily in 28 probands, and MLPA was used in multiplex PCR-negative cases subsequently. The dystrophin gene of the remaining 93 probands and 62 female potential carriers was tested by MLPA directly. In fetuses, multiplex PCR and MLPA were performed on 4 fetuses and 10 fetuses, respectively. In addition, sequencing was also performed in 4 probands with negative MLPA.

ResultsWe found that 61.98% of the subjects had genetic mutations including deletions (50.41%) and duplications (11.57%). There were 43.75% of mothers as carriers of the mutation. In 15 fetuses, 2 out of 7 male fetuses were found to be unhealthy and 2 out of 8 female fetuses were found to be carriers. Exons 3-26 and 45-52 have the maximum frequency in mutation regions. In the frequency of exons individually, exon 47 and exon 50 were the most common in deleted regions and exons 5, 6, and 7 were found most frequently in duplicated regions.

ConclusionsMLPA has better productivity and sensitivity than multiplex PCR. Prenatal diagnosis should be applied in DMD high-risk fetuses to reduce the disease incidence. Furthermore, it is the responsibility of physicians to inform female carriers the importance of prenatal diagnosis.

China ; Dystrophin ; genetics ; Exons ; genetics ; Female ; Gene Deletion ; Heterozygote ; Humans ; Male ; Multiplex Polymerase Chain Reaction ; Muscular Dystrophy, Duchenne ; genetics ; Mutation ; genetics ; Pregnancy ; Sequence Deletion

OBJECTIVETo investigate the value of single nucleotide polymorphism array (SNP array) for the identification of de novo mutations in the DMD gene among fetuses.

METHODSG-banded karyotyping and SNP array were performed on a fetus with intrauterine growth restriction but without family history of Duchenne/Becker muscular dystrophy (DMD/BMD). Multiplex ligation-dependent probe amplification (MLPA) was subsequently applied on amniocytes and maternal peripheral blood sample to detect DMD gene deletion/duplication mutations.

RESULTSKaryotyping of amniocytes showed a normal 46, XY karyotype. SNP array on amniocytes detected a 116 kb deletion (chrX: 32 455 741-32 571 504) at Xp21.1 with breakpoints at introns 16 and 30 respectively, encompassing exons 17-29 of the DMD gene. In addition, MLPA analysis of the DMD gene on amniocytes confirmed the deletion of exons 17 to 29 identified by SNP array. However, no deletion/duplication mutation was detected by MLPA in the mother.

CONCLUSIONThe de novo deletion of exons 17 to 29 of the DMD gene detected in the fetus may result in BMD or DMD. SNP array can improve the efficiency for detecting genomic disorders in fetuses with unidentified pathogenic genes, negative family history and nonspecific phenotypes.

Adult ; Dystrophin ; genetics ; Exons ; genetics ; Female ; Fetus ; abnormalities ; Gene Deletion ; Humans ; Muscular Dystrophy, Duchenne ; genetics ; Phenotype ; Polymorphism, Single Nucleotide ; genetics ; Pregnancy

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 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