Background：Dysferlinopathy is caused by mutations in the dysferlin （DYSF） gene.Here,we described the genetic features of a large cohort of Chinese patients with this disease.Methods：Eighty-nine index patients were...Background：Dysferlinopathy is caused by mutations in the dysferlin （DYSF） gene.Here,we described the genetic features of a large cohort of Chinese patients with this disease.Methods：Eighty-nine index patients were included in the study.DYSF gene analysis was performed by Sanger sequencing in 41 patients and targeted next generation sequencing （NGS） in 48 patients.Multiplex ligation-dependent probe amplification （MLPA） was performed to detect exon duplication/deletion in patients with only one pathogenic mutation.Results：Among the 89 index patients,79 patients were demonstrated to carry two disease-causing （73 cases） or possibly disease-causing mutations （6 cases）,including 26 patients with homozygous mutations.We identified 105 different mutations,including 59 novel ones.Notably,in 13 patients in whom only one pathogenic mutation was initially found by Sanger sequencing or NGS,3 were further identified to carry exon deletions by MLPA.The mutations identified in this study appeared to cluster in the N-terminal region.Mutation types included missense mutations （30.06%）,nonsense mutations （1 7.18%）,frameshift mutations （30.67%）,in-frame deletions （2.45%）,intronic mutations （17.79%）,and exonic rearrangement （1.84%）.No genotype-phenotype correlation was identified.Conclusions：DYSF mutations in Chinese patients clustered in the N-terminal region of the gene.Exonic rearrangements were found in 23% of patients with only one pathogenic mutation identified by Sanger sequencing or NGS.The novel mutations found in this study greatly expanded the mutational spectrum of dysferlinopathy.展开更多
The relative frequencies of different subtypes of limb-girdle muscular dystrophies vary widely among different populations. We estimated the percentage of limb-girdle muscular dystrophy subtypes in Chinese people base...The relative frequencies of different subtypes of limb-girdle muscular dystrophies vary widely among different populations. We estimated the percentage of limb-girdle muscular dystrophy subtypes in Chinese people based on 68 patients with limb-girdle muscular dystrophy from the Myology Clinic, Neurology Department, First Hospital of Jilin University, China. A diagnosis of calpainopathy was made in 12 cases （17%）, and dysferlin deficiency in 10 cases （15%）. Two biopsies revealed α-sarcoglycan deficiency （3%）, and two others revealed a lack of caveolin-3 （3%）. A diagnosis of unclassified limb-girdle muscular dystrophy was made in the remaining patients （62%）. The ap-pearances of calpain 3- and dysferlin-deficient biopsies were similar, though rimmed vacuoles were unique to dysferlinopathy, while inflammatory infiltrates were present in both these limb-girdle muscular dystrophy type 2D biopsies. Macrophages were detected in seven dysferlinopathy biop-sies. The results of this study suggest that the distribution of limb-girdle muscular dystrophy sub-types in the Han Chinese population is similar to that reported in the West. The less necrotic, re-generating and inflammatory appearance of limb-girdle muscular dystrophy type 2A, but with more lobulated fibers, supports the idea that calpainopathy is a less active, but more chronic disease than dysferlinopathy. Unusual features indicated an extended limb-girdle muscular dystrophy disease spectrum. The use of acid phosphatase stain should be considered in suspected dysferlinopathies. To the best of our knowledge, this is the first report to define the relative proportions of the various forms of limb-girdle muscular dystrophy in China, based on protein testing.展开更多
Duchenne muscular dystrophy (DMD) is a lethal X-linked recessive neuromuscular disorder caused by mutations in the dystrophin encoding gene, with the characteristics of a severe and progressive destruction of muscle s...Duchenne muscular dystrophy (DMD) is a lethal X-linked recessive neuromuscular disorder caused by mutations in the dystrophin encoding gene, with the characteristics of a severe and progressive destruction of muscle structure and function. Skeletal muscle fibrosis is one of the pathological features of DMD. Tetramethylpyrazine (2,3,5,6-tetramethylpyrazine, TMP) has been demonstrated to reduce heart and liver fibrosis. Meanwhile, previous studies showed that Tetramethylpyrazine nitrone (TBN), a nitrone derivative of TMP, has promising therapeutic effects in several neurodegenerative models and is more potent than TMP. In this study, we investigated the potential effect of TBN on the <em>mdx</em> mouse model of DMD. Eight-week-old <em>mdx</em> mice were administered with TBN (30 mg/kg) intragastrically twice daily, with deflazacort (1 mg/kg) once a day as a positive control, for a total of 24 weeks. Behavioral tests including pole-climbing open-field test were monitored every 4 weeks. Histopathological assessment was conducted in the gastrocnemius and diaphragm muscles. The effects of TBN on protein levels of dysferlin were measured by immunohistochemistry. TBN significantly reduced the climbing time in pole test and increased the total distance moved in an open-field test of <em>mdx</em> mice. TBN attenuated fibrosis in the gastrocnemius and diaphragmatic muscles. In addition, TBN protected gastrocnemius muscle fibers via increasing expression of the dysferlin in <em>mdx </em>mice. In conclusion, this study demonstrated that TBN could improve the motor deficits and muscle pathology of <em>mdx</em> mouse, and it is worth further exploring the mechanism of action of TBN for DMD treatment.展开更多
文摘Background：Dysferlinopathy is caused by mutations in the dysferlin （DYSF） gene.Here,we described the genetic features of a large cohort of Chinese patients with this disease.Methods：Eighty-nine index patients were included in the study.DYSF gene analysis was performed by Sanger sequencing in 41 patients and targeted next generation sequencing （NGS） in 48 patients.Multiplex ligation-dependent probe amplification （MLPA） was performed to detect exon duplication/deletion in patients with only one pathogenic mutation.Results：Among the 89 index patients,79 patients were demonstrated to carry two disease-causing （73 cases） or possibly disease-causing mutations （6 cases）,including 26 patients with homozygous mutations.We identified 105 different mutations,including 59 novel ones.Notably,in 13 patients in whom only one pathogenic mutation was initially found by Sanger sequencing or NGS,3 were further identified to carry exon deletions by MLPA.The mutations identified in this study appeared to cluster in the N-terminal region.Mutation types included missense mutations （30.06%）,nonsense mutations （1 7.18%）,frameshift mutations （30.67%）,in-frame deletions （2.45%）,intronic mutations （17.79%）,and exonic rearrangement （1.84%）.No genotype-phenotype correlation was identified.Conclusions：DYSF mutations in Chinese patients clustered in the N-terminal region of the gene.Exonic rearrangements were found in 23% of patients with only one pathogenic mutation identified by Sanger sequencing or NGS.The novel mutations found in this study greatly expanded the mutational spectrum of dysferlinopathy.
基金supported by the Chinese Scholarship Counsel's International Students Grant,No.404080022426
文摘The relative frequencies of different subtypes of limb-girdle muscular dystrophies vary widely among different populations. We estimated the percentage of limb-girdle muscular dystrophy subtypes in Chinese people based on 68 patients with limb-girdle muscular dystrophy from the Myology Clinic, Neurology Department, First Hospital of Jilin University, China. A diagnosis of calpainopathy was made in 12 cases （17%）, and dysferlin deficiency in 10 cases （15%）. Two biopsies revealed α-sarcoglycan deficiency （3%）, and two others revealed a lack of caveolin-3 （3%）. A diagnosis of unclassified limb-girdle muscular dystrophy was made in the remaining patients （62%）. The ap-pearances of calpain 3- and dysferlin-deficient biopsies were similar, though rimmed vacuoles were unique to dysferlinopathy, while inflammatory infiltrates were present in both these limb-girdle muscular dystrophy type 2D biopsies. Macrophages were detected in seven dysferlinopathy biop-sies. The results of this study suggest that the distribution of limb-girdle muscular dystrophy sub-types in the Han Chinese population is similar to that reported in the West. The less necrotic, re-generating and inflammatory appearance of limb-girdle muscular dystrophy type 2A, but with more lobulated fibers, supports the idea that calpainopathy is a less active, but more chronic disease than dysferlinopathy. Unusual features indicated an extended limb-girdle muscular dystrophy disease spectrum. The use of acid phosphatase stain should be considered in suspected dysferlinopathies. To the best of our knowledge, this is the first report to define the relative proportions of the various forms of limb-girdle muscular dystrophy in China, based on protein testing.
文摘Duchenne muscular dystrophy (DMD) is a lethal X-linked recessive neuromuscular disorder caused by mutations in the dystrophin encoding gene, with the characteristics of a severe and progressive destruction of muscle structure and function. Skeletal muscle fibrosis is one of the pathological features of DMD. Tetramethylpyrazine (2,3,5,6-tetramethylpyrazine, TMP) has been demonstrated to reduce heart and liver fibrosis. Meanwhile, previous studies showed that Tetramethylpyrazine nitrone (TBN), a nitrone derivative of TMP, has promising therapeutic effects in several neurodegenerative models and is more potent than TMP. In this study, we investigated the potential effect of TBN on the <em>mdx</em> mouse model of DMD. Eight-week-old <em>mdx</em> mice were administered with TBN (30 mg/kg) intragastrically twice daily, with deflazacort (1 mg/kg) once a day as a positive control, for a total of 24 weeks. Behavioral tests including pole-climbing open-field test were monitored every 4 weeks. Histopathological assessment was conducted in the gastrocnemius and diaphragm muscles. The effects of TBN on protein levels of dysferlin were measured by immunohistochemistry. TBN significantly reduced the climbing time in pole test and increased the total distance moved in an open-field test of <em>mdx</em> mice. TBN attenuated fibrosis in the gastrocnemius and diaphragmatic muscles. In addition, TBN protected gastrocnemius muscle fibers via increasing expression of the dysferlin in <em>mdx </em>mice. In conclusion, this study demonstrated that TBN could improve the motor deficits and muscle pathology of <em>mdx</em> mouse, and it is worth further exploring the mechanism of action of TBN for DMD treatment.
