Duchenne muscular dystrophy in a Filipino boy reaching adulthood, and nine years into oral corticosteroids: A case report

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.

Pathologic features of paraspinal muscle biopsies in patients with adolescent idiopathic scoliosis / 北京大学学报(医学版)

OBJECTIVE@#To characterize the paraspinal muscles of adolescent idiopathic scoliosis (AIS) patients, and to further explore its etiology.@*METHODS@#Clinical records and paraspinal muscle biopsies at the apex vertebra region during posterior scoliosis correction surgery of 18 AIS were collected from November 2018 to August 2019. Following standardized processing of fresh muscle tissue biopsy, serial sections with conventional hematoxylin-eosin (HE) and histochemical and immunohistochemical (IHC) with antibody Dystrophin-1 (R-domain), Dystrophin-2 (C-terminal), Dystrophin-3 (N-terminal), Dystrophin-total, Myosin (fast), major histocompatibility complex 1 (MHC-1), CD4, CD8, CD20, and CD68 staining were obtained. Biopsy samples were grouped according to the subjects' median Cobb angle (Cobb angle ≥ 55° as severe AIS group and Cobb angle < 55° as mild AIS group) and Nash-Moe's classification respectively, and the corresponding pathological changes were compared between the groups statistically.@*RESULTS@#Among the 18 AIS patients, 8 were in the severe AIS group (Cobb angle ≥55°) and 10 in the mild AIS group (Cobb angle < 55°). Both severe and mild AIS groups presented various of atrophy and degeneration of paraspinal muscles, varying degrees and staining patterns of immune-expression of Dystrophin-3 loss, especially Dystrophin-2 loss in severe AIS group with significant differences, as well as among the Nash-Moe classification subgroups. Besides, infiltration of CD4+ and CD8+ cells in the paraspinal muscles and tendons was observed in all the patients while CD20+ cells were null. The expression of MHC-1 on myolemma was present in some muscle fibers.@*CONCLUSION@#The histologic of paraspinal muscle biopsy in AIS had similar characteristic changes, the expression of Dystrophin protein was significantly reduced and correlated with the severity of scoliosis, suggesting that Dystrophin protein dysfunctions might contribute to the development of scoliosis. Meanwhile, the inflammatory changes of AIS were mainly manifested by T cell infiltration, and there seemed to be a certain correlation between inflammatory cell infiltration, MHC-1 expression and abnormal expression of Dystrophin. Further research along the lines of this result may open up new ideas for the diagnosis of scoliosis and the treatment of paraspinal myopathy.

Genetic analysis and reproductive intervention of 7 families with gonadal mosaicism for Duchenne muscular dystrophy / 中华医学遗传学杂志

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.

Distrofia muscular de Duchenne, una causa infrecuente de miocardiopatía dilatada / Duchenne muscular dystrophy, a rare cause of dilated cardiomyopathy

Neuromuscular diseases represent a rare cause of dilated myocardiopathy, among them Duchenne muscular dystrophy is the most common. Transthoracic echocardiography and cardiac magnetic resonance imaging can assess cardiac involvement early. The case of a patient diagnosed with Duchenne muscular dystrophy who develops cardiac involvement during cardiology follow-up is presented below.

Clinical aspects, food management, and clinical evolution of a cat with hypertrophic muscular dystrophy / Aspectos clínicos, manejo alimentar e evolução clínica de um gato com distrofia muscular hipertrófica

Hypertrophic feline muscular dystrophy (HFMD), rarely reported in the literature, is a disease caused by a hereditary recessive dystrophin deficiency linked to the X chromosome, mainly affecting young male cats. Here, we presented the clinical aspects, food management, and clinical evolution of a seven-year-old mixed-breed cat diagnosed with HFMD, having a primary history of progressive tongue protrusion.

A distrofia muscular hipertrófica felina é uma doença causada por uma deficiência da distrofina com caráter hereditário recessivo ligado ao cromossomo X, com poucos registros de ocorrência na literatura, que acomete principalmente gatos machos jovens. Neste trabalho, são relatados os aspectos clínicos, manejo alimentar e evolução clínica de um gato, sem raça definida, de sete anos com histórico principal de protrusão progressiva da língua e diagnosticado com distrofia muscular hipertrófica felina.

Genetic analysis of a Chinese pedigree affected with Becker muscular dystrophy with myalgia as the main feature / 中华医学遗传学杂志

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.

Study on newborn screening for Duchenne muscular dystrophy and diagnostic strategy / 中华医学遗传学杂志

OBJECTIVE@#To establish a newborn screening system for Duchenne muscular dystrophy (DMD) through assessment of MM isoenzyme of creatine kinase (CK-MM) activity.@*METHODS@#The CK-MM level was detected using dry blood spot filter paper from 10 252 male newborns. The results were grouped based on their gestational age, sampling time and intervals between the experiments. The threshold value for CK-MM necessitating genetic testing was determined. Next-generation sequencing (NGS) was carried out for those with a CK-MM value over the threshold, and the result was verified by multiplex ligation-dependent probe amplification (MLPA).@*RESULTS@#Based on the result of non-parametric rank sum test, the median CK-MM concentration has increased with the gestational age, and was inversely correlated with the age of the newborns among unaffected specimens. CK-MM on dry blood spot filter paper can be stable for 14 days at 2-8℃. Statistical analysis of CK-MM value of the 10 252 neonates suggested that the threshold may be set as 700 ng/mL. Exonic deletions were found in 2 confirmed cases, whose CK-MM level was greater than 2000 ng/mL.@*CONCLUSION@#Detection of CK-MM in dry blood spot filter paper has provided an effective method for newborn screening of DMD. This simple and inexpensive method can be used for large-scale screening, which is of great value to the early intervention and treatment of the disease.

Variant analysis and therapeutic prospect for Chinese pedigrees affected with Duchenne/Becker muscular dystrophy from a single center over the past 15 years / 中华医学遗传学杂志

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.

Diagnosis of a patient with adjacent gene deletion syndrome with DMD complete deletion type of Duchenne muscular dystrophy / 中华医学遗传学杂志

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.

A predictive analysis of the association between clinical phenotypes and genotypes in children with Becker muscular dystrophy/Duchenne muscular dystrophy / 中国当代儿科杂志

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.

Clinical phenotypes and genetic features of families with Duchenne muscular dystrophy / 中国当代儿科杂志

OBJECTIVE@#To study the phenotypes and genetic features of families with Duchenne muscular dystrophy (DMD).@*METHODS@#Seven children from six families with DMD diagnosed by gene testing were enrolled. The clinical and genetic features of the families were analyzed.@*RESULTS@#There were two new mutations and four maternal inheritance mutations in the six families. The proband of family 1 had one point de novo mutation and one insertion de novo mutation of the DMD gene. Three families had point mutation, one family had fragment deletion of exon, and one family had fragment duplication of exon. The youngest age of onset of the probands was 6 months. All probands had skeletal muscle dyskinesia and significant changes in muscle enzymes, with different severities of clinical phenotypes. Three probands had mild mental retardation. The results of echocardiography were normal for all probands. The mother of the proband in family 6 had mild clinical phenotype.@*CONCLUSIONS@#Gene testing can be used for the confirmed diagnosis of DMD. Mental retardation is a frequent clinical phenotype of DMD. The symptoms of myocardial involvement are not obvious in the early stage. Female carriers may have mild clinical symptoms.

Avances en el tratamiento de la distrofia de Duchenne / Advances in the treatment of Duchenne muscular dystrophy

La distrofia muscular de Duchenne es una enfermedad genéticamente determinada, ligada al cromosoma X y caracterizada clínicamente por producir debilidad muscular progresiva, con una incidencia de 1 por cada 3500-6000 varones nacidos. Es causada por la mutaciones en el gen DMD, el cual codifica la distrofina, una proteína sub-sarcolémica esencial para la estabilidad estructural del músculo. Los defectos genéticos en el gen DMD, se dividen en: deleciones (65%) duplicaciones (5-10%) y mutaciones puntuales (10-15%). Actualmente no se dispone de tratamiento curativo, el único fármaco que ha demostrado modificar la historia natural de la enfermedad (independientemente de la mutación genética) son los corticoides, los cuales están indicados en estadios tempranos de la enfermedad. En relación a los ensayos clínicos, en los últimos diez años se han experimentado grandes avances en el campo de las opciones terapéuticas, divididos en dos grandes dianas terapéuticas: 1) el área de las terapias génicas y 2) tratar de revertir o bloquear los procesos fisiopatológicos de la enfermedad, tales como inflamación, fibrosis, regeneración muscular, etc. Es probable que un tratamiento eficaz para la distrofia muscular de Duchenne requiera combinaciones que se apliquen tanto al defecto primario como las consecuencias fisiopatológicas secundarias.

Duchenne muscular dystrophy is a genetically determined disease, linked to the X chromosome, c haracterized clinically by producing progressive muscle weakness, with an incidence of 1 per 3500-6000 males born. It is caused by the mutation of the DMD gene, which encodes dystrophin, a sub-sarcolemmal protein essential for structural muscle stability. The genetic defects in the DMD gene are divided into: deletions (65%) duplications (5.10%) and point mutations (10-15%). At present there is no curative treatment, the only drug that has been shown to modify the natural history of the disease (independently of the genetic mutation) are corticosteroids, currently indicated in early stages of the disease. In relation to clinical trials, in the last ten years, has experienced great advances in the field of therapeutic options, divided into two major therapeutic targets: 1) the area of gene therapies and 2) trying to reverse or block the pathophysiological processes of the disease, such as inflammation, fibrosis, muscle regeneration, etc. It is likely that an effective treatment for Duchenne muscular dystrophy requires combinations of therapies that address both the primary defect and its secondary pathophysiological consequences.

Duchenne muscular dystrophy: an historical treatment review / Distrofia muscular de Duchenne: revisão histórica do tratamento

ABSTRACT In this review, we discuss the therapies used in the treatment of patients with Duchenne muscular dystrophy since the first description of the disease. A short description is given of the various theories based on disease pathogenesis, which give the substrates for the many therapeutic interventions. A brief review of the methods of evaluation used in therapeutic trials is made. Of all the treatments, the only drugs that are still considered able to modify the course of the disease are the corticosteroids (prednisone/prednisolone/deflazacort). Other drugs (coenzyme Q10 and creatine) have had a little effect in a few functions without adverse reactions. Idebenone seems to improve the respiratory function in the long term. The trials with mRNA transcription, through nonsense mutations or exon 51 skipping, show some beneficial results in a few functional tests, but they are limited to a small set of DMD patients.

RESUMO Nesta revisão são discutidas as terapêuticas empregadas no tratamento da distrofia muscular de Duchenne desde a descrição da doença. Apresentamos as diversas teorias que fundamentaram as intervenções terapêuticas, com uma breve descrição dos tipos de avaliação empregados nos ensaios terapêuticos. Dentre todos os tratamentos, a única medicação que até agora modificou o curso da doença foram os corticosteroides (prednisona/prednisolona/deflazacort). A coenzima Q10 e creatina tiveram algum efeito pequeno em algumas funções e evolução da doença sem efeitos colaterais. O idebenone mostrou efeito benéfico na função respiratória em longo prazo. As tentativas de intervir no gene da distrofina utilizando técnicas de transcrição do mRNA através das mutações sem sentido e técnicas que pulam o exon 51 mostram resultado muito discreto em algumas provas funcionais e limitado a uma parcela pequena de casos.

Three novel splicing mutations at 5' terminal of DMD gene corresponding to different phenotypes / 中华医学遗传学杂志

OBJECTIVE@#To study the correlation of splicing mutations at the 5' end of the DMD gene with their phenotypes.@*METHODS@#DMD gene mutations were analyzed using Multiplex Ligation Probe Amplification (MLPA) and Sanger sequencing. Co-segregation analysis was performed for the pedigrees of the probands. Influence of mutations on protein function was predicted by bioinformatic analysis.@*RESULTS@#Three novel splicing mutations were identified in three patients with different phenotypes. Patient 1 carried a c.31+3insT mutation and presented primarily with dilated cardiomyopathy (XLDC). There was no clinical signs of skeletal myopathy. Bioinformatic analysis predicted that the mutation may inactivate the splicing donor of intron 1 and lead to premature termination of protein translation. Patient 2 carried a c.264_264+4delTGTAA mutation, which led to loss of splicing donor site for intron 4, and manifested Becker muscular dystrophy (BMD). The mutation was predicted to result in skipping of exon 4. The defective protein may still retain most of its function. Patient 3 had Duchenne muscular dystrophy (DMD) and carried a c.832-3C>T mutation which was predicted to decrease the activity of splicing acceptor of intron 8, resulting in usage of alternative acceptor site or retain of intron 8. All related transcripts may cause premature termination of protein translation and complete loss of protein function. The three mutations were all inherited from the mothers of the patients.@*CONCLUSION@#Three novel splicing mutations were discovered at the 5' end of DMD gene in three patients with different disease phenotypes. Our study may facilitate understanding of the influence of splicing mutations at the 5' end of the DMD gene on dystrophin function and the correlation between genotypes and phenotypes.

Application of next-generation sequencing in the molecular diagnosis of Duchenne muscular dystrophy / 中国当代儿科杂志

The purpose of this study is to analyze the family's clinical data of 22 children who were given an intended clinical diagnosis of Duchenne muscular dystrophy (DMD), and to explore the clinical value of next-generation sequencing (NGS) in the molecular diagnosis of DMD. The probands were simultaneously tested by NGS for a gene panel associated with hereditary neuromuscular disease and multiplex ligation-dependent probe amplification (MLPA) for the Dystrophin gene. The exon deletion/repetition mutations of the Dystrophin gene determined by both methods were compared and the point mutations of the Dystrophin gene were verified by Sanger sequencing. Dystrophin gene mutations were found in all the 22 probands, including 14 exon deletion/repetition mutations and 8 point mutations/minor variations. The results of MLPA detection were consistent with those of NGS. The results of Sanger sequencing showed that the point mutations and minor variations determined by NGS were correct. One missense mutation (c.6290G>T), 1 nonsense mutation (c.3487C>T) and 4 minor deletion-induced frameshift mutations (c.1208delG, c.7497_7506delGGTGGGTGAC, c.9421_9422delAA and c.8910_8913delTCTC) had not been reported in the Human Gene Mutation Database, and thus were considered as novel mutations of the Dystrophin gene. The results of this study showed that NGS can detect variations in the Dystrophin gene, including exon deletion/repetition, point mutation, minor deletion and intron mutation. Therefore, NGS is of certain clinical value in the molecular diagnosis of DMD and is worthy of recommendation.

Incidental discovery of DMD gene deletions by chromosomal microarray analysis / 中华医学遗传学杂志

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.

Germinal mosaicism for partial deletion of the Dystrophin gene in a family affected with Duchenne muscular dystrophy / 中华医学遗传学杂志

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.

Molecular Analysis-Based Genetic Characterization of a Cohort of Patients with Duchenne and Becker Muscular Dystrophy in Eastern China / 中华医学杂志(英文版)

<p><b>Background</b>Duchenne 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.</p><p><b>Methods</b>We 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.</p><p><b>Results</b>We 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.</p><p><b>Conclusions</b>MLPA 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.</p>

A retrospective analysis of 6 children with Duchenne muscular dystrophy / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To analyze the clinical features of 6 children with Duchenne muscular dystrophy (DMD) and review related literature, and to provide a basis for early diagnosis and effective treatment of this disease.</p><p><b>METHODS</b>A retrospective analysis was performed on the clinical data of 6 children with DMD who were admitted to the First Affiliated Hospital of Nanjing Medical University from January 2010 to October 2015.</p><p><b>RESULTS</b>All the 6 cases were boys without a family history of DMD, and the age of diagnosis of DMD was 1.2-11.5 years. All patients had insidious onset and increases in alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase, α-hydroxybutyrate dehydrogenase, creatine kinase (CK), and creatine kinase-MB, particularly CK, which was 3.3-107.2 times the normal level. Their gene detection results all showed DMD gene mutation. The gene detection results of two children's mothers showed that they carried the same mutant gene. The muscle biopsy in one case showed that the pathological changes confirmed the diagnosis of DMD. The level of CK in one case declined by 77.0% 5 days after umbilical cord blood mesenchymal stem cell transplantation.</p><p><b>CONCLUSIONS</b>For boys with abnormal serum enzyme levels and motor function, DMD should be highly suspected. It should be confirmed by CK and DMD gene detection as soon as possible. And the progression of the disease could be delayed by early intervention for protecting the remaining normal muscle fibers.</p>

Analyses of exercise-induced muscle damage-specific microRNA expression and molecular target of sarcolemmal damage in rats / 生理学报

In the present study, we were to screen the specific microRNA (miRNA) of exercise-induced muscle damage (EIMD) and assess the EIMD-specific miRNAs-regulated target of sarcolemmal damage in rats. Twenty-four male Sprague-Dawley (SD) rats were randomly divided into 3 groups, which included sedentary (C), 24 h post-exercise (E24) and 48 h post-exercise (E48) groups. Rat EIMD model was established by an acute eccentric exercise, i.e., a downhill running treatment at -16º gradient. EIMD characteristics were verified by Evans blue dye staining, differentially expressed miRNAs were detected by microarray assay, EIMD-specific miRNAs expressions were further validated by real-time quantitative RT-PCR (RT-qPCR), and targets of the miRNAs were predicted based on mRNA expressions of associated proteins and related pathway core molecules of sarcolemmal damage. Two EIMD-specific expressed miRNAs, including miR-206-3p and miR-139-3p, were found in the study. There was a significantly negative correlation (P < 0.05) between miR-206-3p expression and dystrophin (r = -0.68), utrophin (r = -0.64), JNK (r = -0.62) or ERK1 (r = -0.68) respectively, but no correlation was found between miR-139-3p and these biomolecules. The results suggest that: i) the expression profile of miRNAs in rat is significantly affected by EIMD, ii) miR-206-3p and miR-139-3p are the EIMD-specific miRNAs, and iii) miR-206-3p may control sarcolemmal damage by regulating dystrophin, utrophin, JNK and ERK1.