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

OBJECTIVE: To establish a screening model for females of reproductive age carrying Duchenne muscular dystrophy (DMD) variants based on a current community health examination platform. METHODS: A total of 61 870 participants were recruited between October 2017 and October 2019. Serum creatine kinase (CK) was measured with a Roche Cobasc 701/702 using an enzymatic rate method. Genetic testing was offered to those with a CK level of ≥ 200 U/L. For carriers of DMD variants, genetic counseling and follow up were provided. RESULTS: For the 61 870 females participating in the program, 1078 were found with raised serum CK (≥ 200 U/L), of which 618 (57.33%) accepted CK re-measurement after at least a two-week interval. One hundred and twenty cases were found with sustained serum CK elevation, of which 6 were confirmed to be definite DMD carriers regardless of family history. Genetic testing was provided to 33 females with a family history for DMD, and 13 were determined as definite carriers. An affected fetus was detected by prenatal diagnosis. After genetic counseling, the parents had opted induced abortion. CONCLUSION Large-scale DMD carrier screening through a three-step approach based on the current community health examination platform is both feasible and cost effective.
Female ; Genetic Carrier Screening ; Genetic Counseling ; Genetic Testing ; Humans ; Muscular Dystrophy, Duchenne/genetics* ; Pregnancy ; Prenatal Diagnosis

OBJECTIVETo explore the characteristics of DNA mutations underlying Duchenne muscular dystrophy and provide prenatal diagnosis.

METHODSMultiplex ligation-dependent probe amplification (MLPA) and denaturing high performance liquid chromatography (DHPLC) were applied for analyzing DMD gene mutations in 388 unrelated Chinese patients and 53 fetuses.

RESULTSRespectively, 230 and 43 subjects were found to harbor a deletion (59.28%) or duplication (11.08%). Two deletion hotspots were identified, which have located at exons 45-54 and exons 3-19. Duplications were mainly detected at exons 2-43. Point mutations were identified in 29.64% of patients. Fifty three fetuses were prenatal diagnosed, among which 18 were identified as patients.

CONCLUSIONFrequencies of DMD gene deletions and duplications in China are similar to global data. Prenatal diagnosis can help to reduce births of DMD patients.

Asian Continental Ancestry Group ; genetics ; China ; Dystrophin ; genetics ; Exons ; Female ; Humans ; Male ; Muscular Dystrophy, Duchenne ; genetics ; Mutation ; Pregnancy ; Prenatal Diagnosis

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 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 explore the genetic basis for 7 families with gonadal mosaicism for Duchenne muscular dystrophy (DMD). METHODS: For the 7 families presented at the CITIC Xiangya Reproductive and Genetic Hospital from September 2014 to March 2022, clinical data were collected. Preimplantation genetic testing for monogenic disorders (PGT-M) was carried out for the mother of the proband from family 6. Peripheral venous blood samples of the probands, their mothers and other patients from the families, amniotic fluid samples from families 1 ~ 4 and biopsied cells of embryos cultured in vitro from family 6 were collected for the extraction of genomic DNA. Multiplex ligation-dependent probe amplification (MLPA) was carried out for the DMD gene, and short tandem repeat (STR)/single nucleotide polymorphism (SNP)-based haplotypes were constructed for the probands, other patients, fetuses and embryos. RESULTS: The results of MLPA showed that the probands and the fetuses/probands' brothers in families 1 ~ 4, 5, 7 had carried the same DMD gene variants, whilst the probands' mothers were all normal. The proband in family 6 carried the same DMD gene variant with only 1 embryo (9 in total) cultured in vitro, and the DMD gene of the proband's mother and the fetus obtained through the PGT-M were normal. STR-based haplotype analysis showed that the probands and the fetuses/probands' brothers in families 1 ~ 3 and 5 have inherited the same maternal X chromosome. SNP-based haplotype analysis showed that the proband from family 6 has inherited the same maternal X chromosome with only 1 embryo (9 in total) cultured in vitro. The fetuses in families 1 and 6 (via PGT-M) were both confirmed to be healthy by follow up, whilst the mothers from families 2 and 3 had chosen induced labor. CONCLUSION Haplotype analysis based on STR/SNP is an effective method for judging gonad mosaicism. Gonad mosaicisms should be suspected for women who have given births to children with DMD gene variants but with a normal peripheral blood genotype. Prenatal diagnosis and reproductive intervention may be adapted to reduce the births of further affected children in such families.
Male ; Pregnancy ; Child ; Humans ; Female ; Muscular Dystrophy, Duchenne/diagnosis* ; Dystrophin/genetics* ; Mosaicism ; Exons ; Prenatal Diagnosis/methods* ; Nucleotides

OBJECTIVETo study the changes of the intramembrane protein particles of erythrocyte from Duchenne muscular dystrophy (DMD) patients and the gene carriers and to explore the pathogenesis of DMD and the diagnostic value of erythrocyte freeze-fracture technology.

METHODSThe fixed erythrocyte mass was treated to form replica membrane by means of the freeze-fracture technology. Then the replica membrane was observed and a picture was taken under electron microscope. The protein particles of extracellular face(EF) and protoplasmic face(PF) per square were counted. The statistical comparative analysis was performed.

RESULTSThe protein particle counts of EF face and PF face of erythrocyte membrane from DMD patients and DMD carriers decreased obviously in comparison with the normal control group (P<0.001).

CONCLUSIONThe erythrocyte freeze-fracture electron microscopic technology may serve as a method for accessory examination of diagnosing DMD patients and a method for detecting DMD carriers. This investigation material supplies reliable evidence for the theory of the systemic membrane defect of DMD.

Erythrocyte Membrane ; metabolism ; ultrastructure ; Female ; Heterozygote ; Humans ; Male ; Membrane Proteins ; metabolism ; Microscopy, Electron ; Muscular Dystrophy, Duchenne ; diagnosis ; genetics ; metabolism

OBJECTIVETo detect genetic causes of Duchenne muscular dystrophy (DMD).

METHODSNext-generation sequencing was used to detect 6 DMD patients in whom no exonic deletions were detected by multiplex PCR. Sanger sequencing and multiplex ligation-dependent probe amplification were used to confirm the results.

RESULTSOne case was found to have deletions of exons 10 and 11, 1 had exons 16 and 17 duplication, 4 cases have 8 point mutations including c.2776C>T, c.5475delA, c.6391_6392delCA, IVS64+1G>A, c.2645A>G, c.5244G>A, c.7728T>C, c.8729A>T, c.8734A>G and c.8810G>A. The former 4 mutations are suspicious pathogenicity, the other 6 mutations are polymorphisms in population. Three novel mutations (IVS64+1G>A, c.6391_6392delCA (p.Q2131NfsX3) and p.Q926X (CAG>TAG) were not reported before.

CONCLUSIONNext-generation sequencing technology is a useful tool for the detection of deletion, duplication and point mutation, which is valuable for clinical application.

Adolescent ; Base Sequence ; Child ; Genetic Variation ; Humans ; Infant ; Molecular Sequence Data ; Muscular Dystrophy, Duchenne ; diagnosis ; genetics ; Sequence Analysis, DNA ; methods

OBJECTIVETo investigate the feasibility of multiple displacement amplification (MDA) to apply in the non-invasive prenatal genetic diagnosis of Duchenne muscular dystrophy (DMD).

METHODSMaternal blood was obtained from 20 pregnant women at 7 to 25 weeks of gestation. After the discontinuous density gradient centrifugation with Percoll, the fetal nucleated red blood cells (NRBCs) were stained with Kleihauer test. All positive NRBCs were collected by micromanipulator and then performed with MDA. Sex and short tandern repeat (STR) analysis were determind from a small aliquot of the reaction. The origin of NRBCs was verified and prenatal diagnosis of DMD was made at the same time.

RESULTSThe product length of MDA was >15 kb, while primer extension preamplification (PEP) is only about 1 kb. We completed non-invasive prenatal genetic diagnosis of 6 fetus at high risk of DMD using MDA. The results were all coincident with amniotic fluid control.

CONCLUSIONThe MDA method which provides a highly uniform representation across the genome, representing the entire genome with minimal amplification bias, shows good application prospects.

Erythroblasts ; metabolism ; Feasibility Studies ; Female ; Fetal Diseases ; blood ; diagnosis ; genetics ; Humans ; Muscular Dystrophy, Duchenne ; blood ; diagnosis ; genetics ; Polymerase Chain Reaction ; methods ; Pregnancy ; Prenatal Diagnosis ; methods