Duchenne muscular dystrophy (DMD) is an X-linked recessive neuromuscular disorder characterized primarily by progressive degeneration and necrosis of skeletal muscle, resulting from mutations in the Dystrophin gene. Patients with DMD typically present with progressive muscle weakness and atrophy during childhood. Currently, available treatment options for DMD remain limited and their efficacy is suboptimal. This review aims to provide a systematic overview of recent advances in therapeutic strategies for DMD, including an analysis of the mechanisms underlying various treatment approaches, outcomes from clinical trials, and their potential clinical applications, in order to inform and guide clinical decision-making.
Muscular Dystrophy, Duchenne/genetics* ; Humans ; Genetic Therapy

Dystrophinopathies, including Duchenne muscular dystrophy, Becker muscular dystrophy and dilated cardiomyopathy, are X-linked recessive genetic disorders due to variants of the dystrophin gene, which can seriously affect quality of life and health. Genetic diagnosis plays a crucial role in their diagnosis, treatment, and prevention. How to rationally select and standardize the use of various genetic techniques is a skill that clinicians must acquire. By compiling expertise of experts from the relevant areas and guidelines published home and abroad, this consensus has provided a guidance from the perspective of genetic diagnosis for the selection of genetic techniques, testing strategies, and detection process for dystrophinopathies.
Humans ; Quality of Life ; Consensus ; Dystrophin/genetics* ; Muscular Dystrophy, Duchenne/therapy* ; Cardiomyopathy, Dilated/genetics* ; Electrocardiography

OBJECTIVE: To explore the correlation between clinical manifestations of Limb-girdle muscular dystrophy autosomal recessive 9 FKRP-related (R9 FKRP-related) and variants of the FKRP gene. METHODS: Two children who had presented at the Children's Hospital of Nanjing Medical University respectively due to increased serum myocardial zymogram and hepatic dysfunction on September 30, 2018 and August 3, 2018 were selected as the study subjects. Clinical data of the children were collected. Both children were suspected for Duchenne or Becker muscular dystrophy for asymptomatic high creatine kinase (CK) levels. Peripheral blood samples of the children and their parents were collected for whole exome sequencing, and candidate variants were validated by Sanger sequencing. RESULTS: Genetic testing revealed that both children have carried compound heterozygous variants of the FKRP gene. The c.545A>G and c.941C>T variants in child 1 have been reported previously, among which the c.545A>G is a hot spot mutation in the Chinese population. Child 2 has carried c.602T>C and c.961G>A variants, both of which were unreported previously. CONCLUSION Both children have met the diagnostic criteria for LGMD R9 FKRP-related. Carriers of the c.545A>G variant may present milder symptoms. Compared with patients carrying null variants, carriers of compound heterozygous missense variants may present with a milder phenotype, manifesting as asymptomatic high CK level.
Humans ; Child ; Asian People/genetics* ; Genetic Testing ; Muscular Dystrophies, Limb-Girdle/genetics* ; Muscular Dystrophy, Duchenne ; Pentosyltransferases/genetics*

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

Objective: To analyze the clinical and genetic characteristics of pediatric patients with dual genetic diagnoses (DGD). Methods: Clinical and genetic data of pediatric patients with DGD from January 2021 to February 2022 in Peking University First Hospital were collected and analyzed retrospectively. Results: Among the 9 children, 6 were boys and 3 were girls. The age of last visit or follow-up was 5.0 (2.7,6.8) years. The main clinical manifestations included motor retardation, mental retardation, multiple malformations, and skeletal deformity. Cases 1-4 were all all boys, showed myopathic gait, poor running and jumping, and significantly increased level of serum creatine kinase. Disease-causing variations in Duchenne muscular dystrophy (DMD) gene were confirmed by genetic testing. The 4 children were diagnosed with DMD or Becker muscular dystrophy combined with a second genetic disease, including hypertrophic osteoarthropathy, spinal muscular atrophy, fragile X syndrome, and cerebral cavernous malformations type 3, respectively. Cases 5-9 were clinically and genetically diagnosed as COL9A1 gene-related multiple epiphyseal dysplasia type 6 combined with NF1 gene-related neurofibromatosis type 1, COL6A3 gene-related Bethlem myopathy with WNT1 gene-related osteogenesis imperfecta type XV, Turner syndrome (45, X0/46, XX chimera) with TH gene-related Segawa syndrome, Chromosome 22q11.2 microduplication syndrome with DYNC1H1 gene-related autosomal dominant lower extremity-predominant spinal muscular atrophy-1, and ANKRD11 gene-related KBG syndrome combined with IRF2BPL gene-related neurodevelopmental disorder with regression, abnormal movement, language loss and epilepsy. DMD was the most common, and there were 6 autosomal dominant diseases caused by de novo heterozygous pathogenic variations. Conclusions: Pediatric patients with coexistence of double genetic diagnoses show complex phenotypes. When the clinical manifestations and progression are not fully consistent with the diagnosed rare genetic disease, a second rare genetic disease should be considered, and autosomal dominant diseases caused by de novo heterozygous pathogenic variation should be paid attention to. Trio-based whole-exome sequencing combining a variety of molecular genetic tests would be helpful for precise diagnosis.
Humans ; Abnormalities, Multiple ; Retrospective Studies ; Intellectual Disability/genetics* ; Bone Diseases, Developmental/complications* ; Tooth Abnormalities/complications* ; Facies ; Muscular Dystrophy, Duchenne/complications* ; Muscular Atrophy, Spinal/complications* ; Carrier Proteins ; Nuclear Proteins

Female ; Humans ; Muscular Dystrophy, Duchenne/genetics*

OBJECTIVE: To explore the genetic basis of a Chinese pedigree affected with Becker muscular dystrophy (BMD) with myalgia as the main feature. METHODS: Clinical data of the patients and results of auxiliary examinations were retrospectively analyzed. Multiplex ligation-dependent probe amplification and high-throughput sequencing were used to detect potential variants. Sanger sequencing was used to verify the results. RESULTS: The clinical manifestations of the proband included myalgia and elevated serum creatine kinase, which is similar to another patient from the pedigree. Genetic testing revealed that the two patients both harbored hemizygous deletions of exons 10 to 29 of the DMD gene, for which the mother was a carrier. The same deletion was not found in his father. Based on the guidelines from American College of Medical Genetics and Genomics, the deletion was predicted to be pathogenic (PVS1+PM2+PP1). CONCLUSION Myalgia with elevated serum CK may be atypical clinical manifestations of BMD and may be associated with variants in the rod domain of the DMD gene. The deletion of exons 10 to 29 of the DMD gene probably underlay the BMD in this pedigree.
China ; Dystrophin/genetics* ; Female ; Genetic Testing ; Humans ; Muscular Dystrophy, Duchenne/genetics* ; Myalgia/genetics* ; Pedigree ; Retrospective Studies

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 genetic characteristics of 671 Chinese pedigrees affected with Duchenne/Becker muscular dystrophy (DMD/BMD). METHODS: Clinical data of the pedigrees were collected. Multiplex PCR, multiple ligation dependent probe amplification (MLPA), next generation sequencing (NGS), Sanger sequencing and long read sequencing were used to detect the variant of DMD gene in the probands and their mothers, and prenatal diagnosis was provided for high risk pregnant women. RESULTS: Among 178 pedigrees analyzed by multiplex PCR, 44 variants of the DMD gene were detected, with the genetic diagnosis attained in 110 pedigrees. Among 493 pedigrees analyzed by MLPA in combination with NGS or Sanger sequencing, 294 pathogenic/possible pathogenic variants were identified, among which 45 were unreported previously, and the genetic diagnosis attained in 484 pedigrees. Structural variants of the DMD gene were identified in two pedigrees by long-read sequencing. Among 444 probands, 341 have inherited the DMD gene variant from their mothers (76.8%). Among 390 women with a high-risk, 339 have opted to have natural pregnancy and 51 chose preimplantation genetic testing for monogenetic disease (PGT-M). The detection rate of neonatal patients and carriers following natural pregnancy was significantly higher than that for PGT-M. CONCLUSION Combined application of MLPA, NGS, Sanger sequencing and long-read sequencing is an effective strategy to detect DMD/BMD. PGT-M can effectively reduce the risk of fetuses. Above finding has expanded the spectrum of DMD gene variants and provided a basis for reproductive intervention for pregnancies with a high risk for DMD/BMD.
China ; Dystrophin/genetics* ; Exons ; Female ; Genetic Testing ; Humans ; Infant, Newborn ; Multiplex Polymerase Chain Reaction ; Muscular Dystrophy, Duchenne/genetics* ; Mutation ; Pedigree ; 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